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| 11/22 |
| 2013/7/8-8/23 [Science/Physics] UID:54705 Activity:nil |
7/8 Why do immigrants kick ass in science?
http://www.aapt.org/aboutaapt/2013_USPhysicsTravelers_pr060713.cfm
\_ Cuz they have no friends
\_ Cuz excelling in science requires less background of the local
culture than excelling in other areas. |
| 11/22 |
| 2013/5/7-18 [Science/Physics] UID:54674 Activity:nil |
5/7 http://www.technologyreview.com/view/514581/government-lab-reveals-quantum-internet-operated-continuously-for-over-two-years This is totally awesome. "equips each node in the network with quantum transmitters–i.e., lasers–but not with photon detectors which are expensive and bulky" \_ The next phase of the project should be stress-testing with real- world confidential data by NAMBLA. |
| 2013/4/29-5/18 [Science/Physics] UID:54664 Activity:nil |
4/29 "Speed of Light May Not Be Constant, Phycisists Say"
http://www.csua.org/u/100d (news.yahoo.com)
"Two papers ...... attempt to derive the speed of light from the
quantum properties of space itself." (i.e. instead of measuring it) |
| 2013/3/14-5/5 [Science/Physics] UID:54626 Activity:nil |
3/14 "Confirmed! Newfound Particle Is the Higgs"
http://news.yahoo.com/confirmed-newfound-particle-higgs-130317830.html
GREAT!!
\_ so, what's next?
\_ "Q: Why does Higgs Boson have mass?" |
| 2012/10/2-11/7 [Science/GlobalWarming, Science/Physics] UID:54490 Activity:nil |
10/2 Ars takes a tour of SLAC:
http://preview.tinyurl.com/9z37spb [ars] |
| 2012/7/2-27 [Science/Physics] UID:54426 Activity:nil |
7/2 http://news.yahoo.com/apnewsbreak-proof-god-particle-found-131226045.html URL says it all. \_ A comic video helps explain it: http://www.csua.org/u/wxa |
| 2011/7/26-8/2 [Science/Physics] UID:54145 Activity:nil |
7/26 "Hong Kong scientists 'show time travel is impossible'"
http://www.csua.org/u/tvp (news.yahoo.com)
\_ Rest of World Emits Collective 'duh'
\_ I'm no physics wizard. They may have proven that a single photon
does not travel faster than c. But how does this imply that
no physical object can travel faster than c? And how does that
imply that no information can travel faster than c?
\_ tell that to the guys who had the "Time Machine Invented" article.
LESSON: you can't believe the internets for things outside the
scope of knowledge of the avg compunerd. Yes, high end physics,
much like economics, classics, lit theory, politics, and how to
talk to women, are all out of scope. |
| 2011/3/6-4/20 [Science/Space, Science/Physics] UID:54055 Activity:nil |
3/5 "NASA scientist finds evidence of alien life"
http://www.csua.org/u/sov (news.yahoo.com)
WOW!
\_ This was published in the Journal of Cosmology. Here's a
description of the very first paper they published, in 2009:
http://csua.org/u/sp1 |
| 2011/2/11-19 [Science/Electric, Computer/SW/Security, Science/Physics] UID:54035 Activity:nil |
2/11 http://www.tinyurl.com/6zxsqfr Tardis at UCB \_ yeah there are 'tards at ucb alright |
| 2010/9/8-30 [Science/Physics] UID:53950 Activity:nil |
9/5 String Theory and God.
http://www.web-books.com/GoodPost/Articles/SeeGod.htm
\_ "My specialty was in biophysics, not in theoretical physics," That
sums up the rest of his articles - a big copy-and-paste job of
fragments that he doesn't really understand. |
| 2010/4/7-15 [Science/GlobalWarming, Science/Physics] UID:53773 Activity:nil |
4/7 "CERN creates 10 million mini-Big Bangs in one week"
http://news.yahoo.com/s/nm/20100407/sc_nm/us_science_cern
See? I told you that this experiment won't create any black holes that
get out of control and swallow the entire eart&$*(!~#@%& NO CARRIER |
| 2009/12/2-9 [Science/Physics] UID:53557 Activity:nil |
12/2 Looking for a "LHC and Higgs bosom for Dummies" equivalent site.
I'd like to learn more but most sites out there are just way
beyond me. Is there a dummy's version for it?
\_ W = weak force, EM = electromagnetic force, S = strong force,
G = gravity. They're the four forces, and the holy grail of
physics is to unify them all in a single theory -- the Grand
Unification Theory. W, EM, and S have been combined
successfully, but G works so differently that all attempts
to unify it with the others have failed so far. The basic
problem is that general relativity and quantum mechanics
have highly incompatible frameworks, so it's hard to bridge
that gap. String theorists swear they're onto something,
but the jury's still out on that.
<DEAD>abstrusegoose.com/175<DEAD>
\_ Aside from whether or not there is an existing unification
theory for 3 or 4 of the forces, what does it mean by "unifying
the forces into a single theory" in the first place? Does it
mean simply coming up with an equation that involves 3 or 4
variables that represent the forces? Does something silly like
"W + EM + S + G = ma" (ie. total force = mass * accel) count?
-- dummy #2
\_ No, it's more like looking for, "this is why the universe
works the way it does." Right now we have ways to describe
why particles behave the way they do, and why gravity
behaves the way it does, but not both at the same time.
\_ Is "Quantum Physics For Dummies" (ISBN-10: 0470381884) any good?
\- Some of this is pretty hard to understand and watered-down
explanations almost mean nothing. But you can at least get a
sense of what some of the fundamental questions are:
--what are unification and symmetry about?
--where does mass come from
--how many fundamental physical constants are there
--what is the "hierarchy problem" etc.
--what is consistant/inconsistant with the std model
i think "Dreams of a Final Theory" is pretty good, but not
that current. You can also look at Lisa Randall's "Warped
Passages" book (if you were in berkeley cs a while ago, her
Passages" book (if you were in berkeley CS a while ago, her
sister Dana was a grad student here). if you have ome specific
question, i can try to address that. Qs like "what do they
mean by 'the higgs gives rise to mass'" or "what does 'quark
confinement' mean?" have sort of a hand wavey explantions,
while "what is gauge renormalization?" doesnt. |
| 2009/11/11-30 [Science/GlobalWarming, Science/Physics] UID:53518 Activity:low |
11/11 Watch the History Channel today! It's got Oppenheimer and the atomic
bomb history. Did you know at one time 10% of the entire electricity
in the U.S. was used to refine U235 and weapon grade plutonium?
Holy jesus! I wonder how much energy is used to get plutonium fuel
that generates today's nuclear powered electric plant
\_ it talks about the 2 different methods for getting U235. So
I was curious and looked it up:
http://www.physlink.com/Education/askexperts/ae576.cfm
Basically, refine uranium into U235 (0.7%) and U238. But
then it also talks about using U235 to bombarad U238 into
U239, plutonium. How does that work?
\_ Physics is hard.
\_ why the hell did you even bother to answer if
your answer doesn't help
\_ you're new around here, aren't you?
\_ Here then: http://tinyurl.com/yfrepec |
| 2009/5/4-6 [Science/GlobalWarming, Science/Physics] UID:52946 Activity:nil |
5/4 Next-generation stealth technology :-)
http://www.boingboing.net/2009/05/04/art-student-creates.html |
| 2009/4/20-23 [Science/GlobalWarming, Science/Physics] UID:52881 Activity:nil |
4/20 Cold Fusion on 60 Minutes:
http://www.cbsnews.com/video/watch/?id=4955212n |
| 2009/4/20-28 [Science/GlobalWarming, Science/Physics] UID:52875 Activity:kinda low |
4/20 "Stephen Hawking hospitalized, reported very ill"
http://news.yahoo.com/s/ap/20090420/ap_on_re_eu/eu_britain_hawking
Hope he doesn't die until he solves the mystery of the universe(s) for
all of us.
\_ Update:
http://www.msnbc.msn.com/id/30323352
\_ This has all been taken out of context...he went in to get some
26s put on his wheel chair and a couple of other mods and the the
Technician said "It's gonna be ILL!"
\_ Stephen Hawking is overrated
\_ Really? Then who is the forefront guy in the field now? Thx.
\_ Hawking isn't really the foremost scientist, but he's one
of the best at making the concepts accessible.
Filipenko is similar in that way. -tom
\- i think that characterization short changes hawking.
picking a "market leader" may depends on your thoughts
about string theory.
\_ Uh, he's been very ill for decades.
\_ It's nice we're so willing to spend $$ to support
string philosophy, but how about doing some science?
\- you can say string theory has affected the job
mkt but i dont think this is a reasonable crit ...
e.g. LHC is $$$. the waste of $$$ from a science
perspective is humans in space. and a lot of public
money is spent on medican research, if you consider
science beyond fundamental physics.
\_ I slam string philosophy because it is producing
no testable predictions. Engineering
demonstrations such as trips to space have
their uses, and so does medical research, but
have any testable hypotheses come out of many
years of string philosophy? Though perhaps
I should use the less perjorative term
string mathematics, because that is all that
can be said to have come of it. Math is worth
pursuing for its own sake, but I think that
the physicists need to concentrated on producing
some testable hypotheses or look at alternatives.
\_ The LHC will test parts of string theory.
\_ My PhD physicist friend claims that these
tests don't really distinguish string
theory from other available theories.
\_ wow, you have a PhD physicist friend,
you must know what you're talking
about!
\_ You noticed I said "claims"?
Are you too dim to pick up
that this means I don't
necessarily trust he is right?
However, I do grant him some
credibility. What credibility
do you have, asshole?
\_ I have *two* PhD physicist
friends!
\_ I'd put Filipenko in the same category as Neil DeGrasse:
amazingly good at evangelizing science.
\- that short changes Filipenko.
\_ Being a string theorist is a great scam. Its impossible to
prove or disprove any of your data in your thought experiments
while sitting at the cafe in downtown Palo Alto.
\- while all the B School people are earning their bread for sure. |
| 2008/6/22-23 [ERROR, uid:50328, category id '18005#0' has no name! , , Science/Physics] UID:50328 Activity:high Cat_by:auto |
6/22 Glass' solid/liquid nature explained:
http://preview.tinyurl.com/4rh9ro [new scientist]
\- "John Kerry, is glass a solid or a liquid?"
\_ This article is a joke, right?
"Although glass feels like a solid, its molecules cannot quite
settle into a regular 3D lattice and, given enough time, it flows
like a liquid."
Um, no it doesn't flow like a liquid.
\_ It doesn't?
\- yes it does. have you ever seen multi-hundred year old windows?
without obsessing over the "like a liquid part", glass does flow.
\_ Have you ever seen really old windows? -- ilyas
\_ No, it doesn't. Otherwise all glass bottles over a certain
age would be glass puddles. Yet we have them from the middle
ages. It's a common misconception, most likely due to early
glass pane making techniques that made glass panes thicker on
one end than another. Now, when people point out the thicker
bottom on glass panes they say that's proof that it's a
liquid. They conveniently overlook panes with thicker tops
and sides. The real slowest solid-like liquid is pitch IIRC.
http://www.physics.uq.edu.au/pitchdrop/pitchdrop.shtml
\_ Why not put the whole setup in a centrifuge to accelerate
the process? |
| 2008/6/15-20 [Science/Physics] UID:50263 Activity:nil |
6/15 Plastic Semiconductors:
http://preview.tinyurl.com/4jbbzl [new scientist] |
| 2008/4/16-23 [Science/Physics] UID:49758 Activity:nil |
4/16 This article sort of argues that we should have set of odds to gauge
how likely it is the CERN will destroy the earth. I'm not quite sure
how one would take odds on somehting we basically think is impossible.
http://csua.org/u/lak (NYTimes)
4\
/16 Pope fashion show! I had no idea he had so many outfits.
http://www.time.com/time/photogallery/0,29307,1730229,00.html
\_ Hello, I am offering Earth destroyal insurance at the modest
cost of only $100. Should the Earth be destroyed by CERN,
I will pay each policy holder $10M. Policy only good for
lifetime of holder. |
| 2008/3/19-21 [Science/Physics] UID:49497 Activity:moderate |
3/19 This is one of the funniest xkcd's I've seen
http://xkcd.com/397
\_ This xkcd is not funny. This is one of the funniest xkcd's you have
ever seen. Therefore, you do not like laughing. ^
\_ You're an idiot |
\_ O WAU YR RITE |
\_ Yes, this is the level of the argument of the gp.
\_ MythBusters is totally bad science. The kind of bad science that
leads to "proving" theories that are completely invalid. XKCD
is wrong wrong WRONG about this one.
\_ You are precisely the kind of person Zombie Feynman would
bitchslap.
\_ My problem is not rigor. My problem is tests that don't
disprove the hypothosis. Hypothosis is "can x be done".
The test is "can I do x via method y". That may doesn't
disprove "can x be done". (Basically I'm sick of know-it-alls
telling me mythbusters proved something doesn't work
when mythbusters did no such thing. People aren't learning
to create tests and verify, people are learning "trust
the geeks on my tv".)
\_ How would you disprove "x can be done"?
\_ You can't. But you go do a lot better than "Can we go
faster than the speed of light? Well we built a really
cool rocket car and it only got to 300mph, so we are
going to say NO!"
\_ Wow, with strawmen like that I can see how you're a
much better thinker than the MythBusters.
\_ Well, it is probably impossible to show that in an
absolute sense most X cannot be done or some phenomenon
X is impossible. The best that one can hope for is that
if X was possible it would violate the known laws of
physics.
Re Mythbusters - I think they pick things that can be
disproven/proven for pratical purposes via a reasonable
experiement. I think of it as a first approximation,
rather than the final proof. Sometimes an approximation
may "promote the Progress of Science and useful Arts"
as much as a final proof will.
\_ I'm sorry, they are bad science. 0 controls.
Multiple independant variables. This kind of
stuff matters and isn't hard to get right.
Why don't they?
\_ They routinely have controls. So you don't watch
the show, eh?
\_ When did they ever call themselves scientists?
They're special effects engineers putting together
an entertaining program. Seriously people...
And the XKCD isn't putting them forth as
scientists either. Whatever you're arguing is
missing the point.
\_ Okay, so they are engineers rather than scientists
:-). In any case, the presenters are doing
"science" in that they are are verifying claims
via experiment, albeit very crude and imprecise
experiments. Sure you can probably do a better,
more precise experiment, with controls, &c. But
it would probably be far less entertaining.
If you want rigor, watch Nova.
\_ Didn't Nova do a huge string theory special?
-- ilyas
\_ Well, they had a big 2 hour special
with Brian Greene based on "The Elegant
Universe." I think they have had a few
shorter shows on loop quantum gravity,
string/m-theory, &c. with Neil deGrasse
Tyson. Most of the Nova episodes re string
or m-theory have included some discussion
that the theory may not be physics b/c it
is untestable.
\_ I don't remember Nova string theory stuff
being anything other than a huge
cheerleading PR thing for string theory.
-- ilyas
\_ Hmm. I recall the string theory pgms
as being mostly cheerleading, but not
totally one-sided. Also there was a
program on LQG, which, I think, is a
different, testable, theory that
unites GR and QM w/o all the kookiness
of string/m-theory.
\_ Who is more anoying, Brian Greene or
Neil deGrasse Tyson?
\_ Not sure, but Samantha Carter recently
said that she thinks Neil deGrasse
Tyson is hotter.
\_ You're blaming Mythbusters for stupid people. They're
pretty good at narrowing their focus and explicitly saying
what that focus is. Instead of mental wanking (like people
asking about a plane taking off from a treadmill), they
actually try it. That *is* valuable, and that's precisely
what Zombie Feynman's point was. It's also a really good
shot at string theorists.
\_ Mythbusters isn't trying to prove that it impossible for
X to be done by any method. I think it is fairly obvious
from the show that the presenters pick the methods most
likely to accomplish X and then show whether X can be
accomplished via those methods. If it turns out that X
cannot be accomplished via the methods selected, then
the presenters conclude that it is unlikely that X can
accomplished. Although it is not a rigorous proof that
X cannot be accomplished at all, the demonstration can
be considered a sufficient approximation for most purposes.
The show can also be considered to as "educational" in the
sense that it teaches people to disbelieve claims that
cannot be demonstrated via experiment.
\_ Ack this is just bull. Something either is, or isn't.
You're either with us, or against us, it's as simple
as that!
\_ Does this pass for humor in your circles? |
| 2007/10/21-25 [Science/Physics] UID:48401 Activity:moderate |
10/21 I am one of the biggest sceptics of Roomba iRobot. 2 of my friends
had the first and second generation Roomba respectively, and their
feelings for it were lukewarm. Their units were loud, a hastle to
use (need to find the unit and charge manually), and most
importantly, DUMB. Well, after doing an extensive research, I
decided to buy the latest Rooma anyways. I got a Roomba 560,
the FIFTH generation and boy, it is the most amazing thing I've
even seen and cleans amazingly well! Here are the highlights:
1) auto docks when it is done or gonna die. The homing beacon
mechanism is amazing!!! 2) 7 day timer so you don't even have to
press start 3) cleans very well, goes under my bed too! 4) it's got
external corner brushes to clean the sides REALLY well, in fact
better than my regular vacuum cleaner 5) it comes with 2 virtual
wall/room units, so you can block or request to clean up to 3
different rooms (and it'll remember which room it is in) 6) it is
a lot quieter than the first generations and lastly 7) it is
a LOT smarter than the first and second generation Roomba and
statistically goes through different surfaces quite evenly. It
knows to clean the sides (did I mention it's got side brushes?).
Roomba 5th generation is a quantum leap from the first few
generations, and it's worth every penny. Good job iRobot, looking
forward to buying your stock.
\_ can it do stairs?
\_ No because it doesn't have a penis.
\_ Assuming it can't do stairs, can it not fall down stairs
if it is upstairs? Is it smart enough not to go over a
cliff?
\_ It cannot do stairs, there are no vacuum robots today
that can do stairs. It does have fall/cliff protection
so you don't have to worry about a thing. If you're
curious just check out some Roomba 560 vids on YouTube.
\_ I'm not sure how 'newer' models do with stairs, but ours
has managed to go fall down our stairs once or twice
when let loose in the upstairs. My current peeve is the
irobot can be activated unexpectedly by a cat walking
on its power button. -ERic
\_ Uh, ya, blame it on the machine and not the cat.
Brilliant. How about putting a cardboard on top
of the button? Actually, I'm curious Eric. Do you
have no pet peeve with cats? What do you like
about cats?
\_ I'm sorry to hear that. I don't seem to have that
problem with my dog.
\_ Cats are programmed statistically to walk on every
horizontal surface in a house 1-4 times a day.
\_ LOL. My Roomba is just as entertaining and
smart as my cat, but my cat is still cuter.
\_ I don't get it. Is running a vaccuum over a floor every so often
so hard you need a toy to do it for you?
\_ It is tedious when you have pets and/or children. In my case
any hour I can gain a week is a HUGE gain -tired guy w/chores
\_ Is this the life you planned for yourself? Is it worth it?
\_ Most of the people in this world don't plan every little
detail of their lives. Most kids, even in developed
countries, are still "accidents."
\_ Sex without condom/pill/whatever that leads to
children is not an accident. The failure rate for
various methods is under 10% on average. If he has
kids, odds are greatly in favor of him planning on it.
\_ abortion or lack thereof is also a choice
\_ True. So all these parents in one way or another
have chosen it. Which goes back to my original
questions to the tired guy w/chores,
"Is this the life you planned for yourself?
Is it worth it?"
\_ I am not tired guy with chores, but I too have
a daughter that keeps me busy and I can say
without reservation that it is the greatest
thing I have ever done. Even if I do have to
hire a maid to clean the bathroom, since I
am too busy (usually playing with my daughter)
to do it myself.
to do it myself. And yes, this is the life I
planned for myself. |
| 2007/10/8 [Science/GlobalWarming, Science/Physics] UID:48270 Activity:nil 52%like:48271 |
10/8 Question for the motd physics geeks. I was talking to some friends
about flywheels. It's well known that one problem with flywheels is
their resistance to rotation (it's the well known effect that keeps
bicycles upright). One proposed way of handling this is to install
flywheels in pairs so they counteract each other. The question is,
how much energy should you expect to bleed off in this way? -- ilyas |
| 2007/10/1-5 [Science/GlobalWarming, Science/Physics] UID:48215 Activity:high |
10/1 "Time travel machine"
http://cosmos.bcst.yahoo.com/ver/246/popup/index.php?cl=4277716
Is this real?
\_ http://en.wikipedia.org/wiki/Ronald_Mallett
There was a piece on him on This American Life that was utterly
heartbreaking. An amazing person.
\_ I can't see the top link, but the wiki article makes it clear
that to this point he doesn't even having a working theory as
to how time travel might work.
\_ It's a hard problem when you're sane.
\_ I think that drawing this conclusion from a wikipedia article
really does justify the fears that people have about the
level of misunderstanding something like wikipedia can
engender. He appears to be both sane and knowledgeable enough
to be worth listening to.
\_ Wikipedia is shit. Citing wikipedia on a subject
generally signals 'I know nothing about the subject
area.'
\_ Uhm, what? This is *time travel*! There is no one on
the planet who truly understands *time travel*. Going
to wikipedia is better than reading this guy's papers
that no one is going to understand. Hey, did I mention
this was about *time travel*? *TIME TRAVEL*! Sheesh.
\_ No it's not. One of the reasons wikipedia is so
dangerous is it makes people think it's a better
source than the source, so to speak. Your first
impulse if you don't understand something is to try
to understand it, or ask someone who does understand,
not consult wikipedia. In this case, if you want
to know if the guy is a kook, talk to a physicist.
Wikipedia is the source of McDonaldization of
Wikipedia is a source of McDonaldization of
\_ This is an excellent
phrase. I hope you don't
mind if I adopt it.
\_ This is due to George
Ritzer. At any rate,
ideas belong to all
mankind. -- ilyas
knowledge. -- ilyas
\_ Lacking any physicists nearby who understand the
math and high energy physics involved in this
guy's work, I'll take the dime store version at
wp. Lacking the time and honesty, having a great
deal of apathy towards the entire time travel
silliness, I'll skip trying to decipher his
actual papers and be satisfied knowing that he's
having fun at some Uni tucked harmlessly out of
the way mumbling, "They mocked me at the Academy!
But I'll show them! I'll show them alllll!!!!!
Muahahahhahahaaa!!!!!" *TIME TRAVEL*!
\_ You are better off simply admitting ignorance
than assuming a contrarian is wrong simply
because he's a contrarian. Biased certainty
is not better than unbiased uncertainty.
If you are interested in rationally evaluating
things, that is. It's great fun to poke fun
at contrarians. -- ilyas
\_ tell us about the stars, ilyas
\_ Uhm, duh, it is *TIME TRAVEL*. How can I
not be ignorant of it? That is what I've
been saying since this topic went up. Please
do tell exactly who on this planet is not
ignorant of how *TIME TRAVEL* works. It is
great fun to poke fun at people who try to
seriously discus *TIME TRAVEL* as if it was
something we could rationally discuss as a
scientific concept and not a philosophical
one. And yes when I finish my *TIME TRAVEL*
machine I am so going back to whack your
grand dad just to put an end to this silly
nonsense. Nothing personal, I think you're
an ok guy.
\_ Time travel is a scientific concept.
You are operating using a very strange
distinction between science and
philosophy. -- ilyas
\_ Wikipedia is great for some things. One prof's
vaugly out there research is not one of those
things.
\_ The problem with wikipedia for 'some things' is
you never really know if the information is
accurate. So the only thing wikipedia is good for
is procrastinating.
\_ 1. Many times I do know if the information
is accurate, or it's not something I'm
worried about being exactly right.
2. If I do care about if information is right
using wikipedia as my only or primary source
is fucking stupid, yes, however it can be
a very useful starting point. Go to wikipedia
get the basics and then research those to
make sure they seem reasonable.
3. The problem with this prof isn't the accuracy
or lack thereof. The problem is it's a poorly
written article about something very few people
care about. What it told me was this dude is
someone who cares a lot about time travel and
has done research in the field that isn't
obviously batshit insane. If I want to know
more I can research other places and come to
my own conclusions.
\_ On a vaguely related note there is some good discussion on the
blogs about 'contrarian' vs 'conservative' strategies in science.
-- ilyas |
| 2007/9/18 [Science/GlobalWarming, Science/Physics] UID:48098 Activity:nil 75%like:48099 |
9/18 "Shrinking kilogram bewilders physicists"
http://news.yahoo.com/s/ap/20070913/ap_on_sc/shrinking_kilogram
*The* kilogram is getting smaller in mass. |
| 2007/6/1-5 [Science/GlobalWarming, Science/Physics] UID:46831 Activity:nil |
6/1 Boeing scientists create 40% efficient solar cells:
http://www.physorg.com/news99904887.html
\_ What's the efficiency of solar cells in typical roof-top solar
panels these days? |
| 2007/4/11-12 [Science/GlobalWarming, Science/Physics] UID:46260 Activity:high |
4/11 Motd poll: What do you think the Easter Islander that chopped down
the last Easter Island tree was saying as he did it?
"Jobs, not trees!":
"Technology will solve our problems, never fear, we'll find a
substitute for wood.":
"We don't have proof that there aren't palm trees somewhere else
on Easter, we need more research, your proposed ban on logging
is premature and driven by fear-mongering":
"this is gonna make a nice fire to cook my dinner on"
"I better take this tree now, before my neighbor does"
\_ "This ought to make sierra-club libural hippies in SF cry."
\_ You sure are smart.
"Jobs, not trees!":
"Technology will solve our problems, never fear, we'll find a
substitute for wood.":
"We don't have proof that there aren't palm trees somewhere else
on Easter, we need more research, your proposed ban on logging
is premature and driven by fear-mongering":
"this is gonna make a nice fire to cook my dinner on"
"I better take this tree now, before my neighbor does"
\_ On a funny note, I saw a Fox news blurb yesterday about how
trees may cause global warming.
\_ "I'm sure this isn't _really_ the last tree."
\_ "As history has demonstrated, we will always invent newer and
newer technologies to locate more and more trees that we can't see
now as tree-cutting rate goes up and up. These will include, but
not limited to, technologies to find transparent trees, trees that
float at 20000ft altitude, quantum trees that have no fixed
position, as well as anti-metter trees. Our tree supply will be
limitless."
\_ Whatever they said, if they said anything, I'm sure it wasn't
in English. ;-)
"You've seen one tree, you've seen 'em all." |
| 2007/3/20-22 [Science/Physics, Computer/Theory] UID:46030 Activity:nil |
3/20 E8 Lie group mapped:
http://www.aimath.org/E8/E8release.txt
http://www.aimath.org/E8
\_ "While many scientific projects involve processing large amounts of
data, the E8 calculation is very different, as the size of the
input is comparatively small, but the answer itself is enormous,
and very dense." How is E8 significant in this sense? I can
easily state a problem like "Find the first N prime numbers." and
input N=1000000". Then the input is small and the answer is
enormous and it involves lots of computation. Is that the same?
\_ How about "what is the ratio of the circumference of a circle
to it's diameter, to 10^8 places"? |
| 2007/2/22-26 [Science/Physics, Science/GlobalWarming] UID:45790 Activity:nil |
2/22 Element 118 created ... in Iran!
http://www.livescience.com/forcesofnature/061017_ap_heavy_element.html
\- e118 created ... "again"
in other news, berkeley >> the 'fraud
berkeley: http://csua.org/u/i3e
'fraud: http://csua.org/u/i3f |
| 2006/10/5-7 [Science/Physics] UID:44683 Activity:nil |
10/5 Beam me up Hamlet:
http://tinyurl.com/krwwg (cnn.com) |
| 2006/9/19-22 [Science/Electric, Science/Physics] UID:44441 Activity:nil |
9/19 Cornell researchers invent oled that also acts as a solar cell:
http://tinyurl.com/eowls (scenta.co.uk)
\_ Awesome, finally my solar powered flashlight will be a reality! |
| 2006/5/11-17 [Science/Physics] UID:43023 Activity:nil |
5/11 Physics question. Why doesn't the Weak Nuclear Force fall off
inversely proprotionally to the square of distance?
\- Oh hello, this is a good question and "why is the weak force not
like the em force or gravity" is one of the great results of
THE STANDARD MODEL. I am going to assume you have taken a little
bit of quantum mechantics but not quantum field theory, so this
will be a little bit hand-wavey. Basically, the weak force is
different from the em/gravity because unlike the photon [em]
and the graviton, THE FORCE CARRIERS FOR THE WEAK FORCE ARE
NOT MASSLESS PARTICLES [see W+ W- and Z particles]. The hand-
wavey part is: higher masses are associated with higher energies
which in turn are associated with smaller interaction distances.
This comes from the uncertainty principle and some dictates of
relativity [speed of light constant and finite] but that is beyond
the motd. Why the weak force carriers have mass is at the cutting
edge of HEP research in a area called the HIGGS MECHANISM. The
LHC coming online at CERN in about a year should be producing
some amazing and eagerly anticipated results "soon". To go up a
notch from here, this length-energy relationship is why STRING
THEORY involves lengths so many orders of mag smaller and energies
so many orders of mag higher [the WEAK SCALE and the PLANK SCALE
about 16-17 orders of mag apart]. another cool thing about the
weak force is PARITY VIOLATION, which if you have taken a little
intro QM is related to the spin statistics. BTW, the weak force
also proves god does not exist. ok tnx. --psb
\- hey this was a pretty good explanation. I took particle physics
and was about to write something but then psb pwned it. good
job! -linxu. ps: wikipedia has much on this. pretty accurate.
\- which class is "particle physics"? there is an upper div
quantum class and a special relativity class, but is there a
particle physics class before 221? BTW, do you have any
preferences between the ZEE and WEINBERG QFT books?
"QFT is hard. let's go shopping."
\- oh the wikipedia entry on the "weak force" is pretty good.
(meaning it is comprehenssable)
i thought it was kinda funny they "hand waved" over the
same part i did: "uncertainty+special relativity -> short
interaction distance", but i guess it makes the additional
point about particle life time. BTW, here is some interesting
trivia about the parity violation: YANG & LEE did the
theoretical work to predict this. apparently they took a
class at UCHICAGO from S CHANDRASEKAR (possibly with some-
body else too) and it turns out that everybody in that class
would go on to win the nobel prize in physics ... in fact
the teacher himself would be the last person to win the
nobel. also, perhaps even a greater scandal than the
WATSON/CRICK/WILKINS vs ROSALIND FRANKLIN female nobel snub
was not naming WU along with YANG and LEE for the parity
violation nobel (since you are allowed to name up to 3
co winners). WU also did her phd at UCB under EOLAWRENCE.
\- which particle physics course? i didnt think there was a
particle physics class until after 221. what textbook do
you use ... WEINBERG or ZEE? ("QFT is hard")?
the wikipedia entry on the "weak force" is pretty good.
(meaning it is comprehensable). i thought it was kinda funny
they "hand waved" over the same part i did:
"uncertainty+special relativity -> short interaction
distance", but i guess it makes the additional point about
particle life time. BTW, here is some interesting trivia
about the parity violation: YANG & LEE did the theoretical
work to predict this. apparently they took a class at
UCHICAGO from S CHANDRASEKAR (possibly with somebody else
too) and it turns out that everybody in that class would go
on to win the nobel prize in physics ... in fact the teacher
himself would be the last person to win the nobel. also,
perhaps even a greater scandal than the WATSON/CRICK/WILKINS
vs ROSALIND FRANKLIN female nobel snub was not naming WU
along with YANG and LEE for the parity violation nobel (since
you are allowed to name up to 3 co-winners). WU also did her
phd at UCB under EOLAWRENCE.
\- Woo that's pretty interesting to know. I took 129A. It was
taught by Gaillard, an old professor who actually did
stuff back in the day. To be honest, most of the math
went over my head... I got a B+ in the class but I don't
deserve it. (Really i should have gotten a C). Some
really interesting stuff re: renormalization, Feynman
diagrams, etc. -linxu
\- oh i was kinda curious if it was MKG or ZUMINO ...
i didnt think the dept let them near undergrads.
BTW, another interesting bit of trivia maybe for
some of you: some of you may have had DANA RANDALL
as a TA for a CS THEORY class ... her sister LISA
did her postdoc at UCB/LBL is now a prominent
physicist and just came out with this book:
http://csua.org/u/fuj
which should cover some of the topics above
at a level accessible to a reasonable sloda user.
BTW, for berkeley MKG isnt that "old" ... not with
people like Al Ghiorso still around ... who started
working for SEABORG in the 40s.
\_ What's with the caps?
\- high speed keyword matching. sort of like compiler hints. |
| 2006/3/27-29 [Science/Physics, Reference/History/WW2] UID:42450 Activity:kinda low |
3/27 This is a very stupid and specific question regards to design
of main battle tank:
why the main gun of most of main battle tank in the world are
smoothbored instead of rifled?
\_ Just a guess but the advent of laser guided missiles obviated the
need for point-to-point riffled payloads. In another word there
is no longer a clear need for line-of-sight with modern missiles.
\_ I'm not an MBT designer, but I would guess that they're able to
accomplish the desired accuracy/range with a smoothbore, and a
rifled shell has less explosive power (because it needs a heavier
casing to withstand the greater stress of the rotation). Mortars
shells contain more explosive than equivalent-sized artillery shells
for the same reason (which makes them particularly deadly for
urban fighting). Oh, and the M1 (but not the A1 or A2 variants)
and the new Stryker multi-tank-thing, plus the British Leopard and
a few others, all have rifled cannon. -gm
\_ Find-stabilized shells, among others. Not all MBT barrels are
smoothbore (examples are Rheinmetall 120mm and several of the
newer Soviet ones.) What above poster said too, but it's not so
much the explosive power as for accuracy of heavier shells. Also
rifled barrels wear out faster. -John
\_ http://en.wikipedia.org/wiki/Smoothbore
\_ thanks. This is cool.
\- Hello, I too am not a MBT designer but having some knowledge of
EULER && LAGRANGE && NEWTON, I suspect the Moments of Inertia
which would characterize a tank shell would suggest it would not
be amenable to rotional stabilization as a small, cigar shaped
shell would be. For a discussion accessible to a science undergrad
see e.g. http://farside.ph.utexas.edu/teaching/336k/lectures/node74.html
particlarly the two conclusions at the bottom of the page. For a
more involved discussion, see the famous: http://csua.org/u/fc6
A simple demonstration of this can be done with a bed pillow
which isnt too floppy. say it is 20" long, 14" wide and 6" deep.
which isnt too floppy. say it is 2ft long, 1.5ft wide and 6in deep.
if you throw it up in the air in front of you spinning about each of
the possible axes, you will notice it is obviously less stable when
you spin it about the 1.5ft axis or "middle" Moment of Inertia axis.
you spin it about the 14" or "middle" Moment of Inertia axis.
This is actually something pretty cool to prove, rather than just
one of these artificial physics problems. And now we can talk about
THE FEYNMAN SPRINKLER.
\_ My classical mechanics text called this The Tennis Racket Theorem.
I tend to think a better example is with skateboards. Rotating
around the principle axis with the smallest moment of inertia
is a kickflip, rotating around the axis with the largest moment
of inertia is a varial or a shove-it, but the unstable middle
axis is called the "ollie impossible" for good reason. Both
the kickflip and the varial can be done by just kicking the
board and landing, but the impossible generally involves guiding
to board around with your foot to keep it stable. At least that's
how I do it. I could kickflip and varial years before I learned
the imposible, which I think you'll find is typical of most
skaters. Of course I could do all three years before I
knew what a moment of inertia tensor was or could prove the
tenis racket theorem.
\_ My classical mechanics text called this The Tennis Racket
Theorem. I tend to think a better example is with
skateboards. Rotating around the principle axis with the
smallest moment of inertia is a kickflip, rotating around the
axis with the largest moment of inertia is a varial or a
shove-it, but the unstable middle axis is called the "ollie
impossible" for good reason. Both the kickflip and the varial
can be done by just kicking the board and landing, but the
impossible generally involves guiding to board around with
your foot to keep it stable. At least that's how I do it. I
could kickflip and varial years before I learned the
imposible, which I think you'll find is typical of most
skaters. Of course I could do all three years before I knew
what a moment of inertia tensor was or could prove the tenis
racket theorem.
\- Oh, i havent heard that name. what CM text? that is a pretty
good name, although since a rackt isnt symmetric in one of
the axes, people may get distracted by that. i didnt claim
a pillow was the best object to demonstrate, but i think more
people on the motd have a pillow than a skateboard. but sure,
i think people have an intuitive sense of the instability of
of the "middle rotation" with the s'board and racket. i always
liked the calculations/proofs that had physical interp ...
kepler planet laws, calculate escape velocity, period of a
pendulum indep of mass ... more than the contrived problems.
\_ Barger and Olsson, which I loathed.
http://www.amazon.com/gp/product/0070037345/sr=8-2/qid=1143569740/ref=sr_1_2/103-6187066-5024642?%5Fencoding=UTF8
I really liked that class, and learned from a mix of
different books plus lecture, but I do not recomend this
book except for a couple random topics. I see what you
mean about pillow vs. skateboard. I guess my point is
that while the typical pillow user does not do a whole
lot of rotational mechanics experiments, the typical
skateboard user spends hours and hours conducting those
experiments and develops a certain intuition about it.
\_ I replied earlier and it got deleted. The text was
Barger and Olson[sp?], which I do not recommend. The class
kicked ass, but that text was overall pretty weak. I see
what you mean about more people having access to a pillow.
My arguement is that while there are fewer skateboard users
than pillow users, most pillow users rarely do rotational
mechanics experiments with their pillows whereas skaters
spend so much time doing these experiments that they have
multiple names for all three of the principle axes. Also,
I think a lot of non-skaters now know what the kickflip
and the ollie impossible are because of that Tony Hawk
video game.
\- oh, i have not heard of that book. i didnt think
MARION and THORNTON was that exciting. GOLDSTEIN
was really good but pretty hard. herstein:algebra::
goldstein::mechanics. VI ARNOLD was life changing, but
really that is an EVANS HALL book not a LECONTE book.
have you also used LANDAU and LIFSHITZ? I have only
analyized their awesome Stat Mech book, but their
Classical Mech book is also supposed to be awesome.
BTW, the AMAZONG comments for some of these books
are pretty funne, esp for MISNER && THORNE && WHEELER.
oh, i suppose you can alos do the "tennis racket"
experiment with an UNOPENED CEREAL BOX.
One of my favorite AMAZONG comments is from UCB
MONSTER FIELDS PROFESSOR about BOGOLIUBOV QFT book
at: http://csua.org/u/ahe
\_ I think the Jackson comments on Amazon are some of
the funniest. Also the comments on Wolfram's
latest doorstop are hillarious. Yeah, L&L rules.
I used that a bit during the course. Where you a
physics major, or are you just into it for fun?
\_ started in physics but didnt want to do 111
and a year of 110 [i spent some time designing
the polarimetery system of a satellite so i
got enough EM on the job] so ended up doing
a lot of work in smplectic geometry and
ergodic theory and lie algebras.
\_ thanks... i flunked my Fizzix 7A :p
\_ I tried the pillow experiment. That is cool. |
| 2005/11/23-28 [Science/Physics] UID:40715 Activity:nil |
11/23 Physicists at UCR may have made positronium:
http://www.nature.com/news/2005/051121/full/051121-4.html
\_ I find it hard to believe that a positron/electron atom could
exist, and the evidence they've presented is pretty weak.
\_ if you bothered to read the article, the positronium atoms
are a given at this point, and have been made. What they
are announcing is evidence that they made Molecules out of these
atoms.
\_ reading is hard; let's play motd! |
| 2005/11/17-19 [Science/Physics] UID:40637 Activity:kinda low |
11/17 Warp Drive Patented:
http://tinyurl.com/dhp8q
\_ While this patent is clearly bullshit, it is not completely clear
that Podkletnov's work is all bullshit. It's true that no one
has been able to duplicate it, but Podkletnov is a very odd
person, and has been very paranoid about giving out certain key
details about how to duplicate the experiment because he hopes
to perfect it on his own with a shoestring budget and get rich
off of it. A friend of mine is totally obsessed with this work,
and is neither a believer nor a total skeptic, but has spent time
sniffing around in Europe, talking to some of Podkletnov's
co-authors trying to get to the bottom of this, and he's still
not convinced either way. Part of what's interesting about it
is that since no honest person seriously claims that high T_C
superconductors are understood, there's plenty of room for crazy,
unanticipated physics, and some theorists have been able to make
crap up that might support Podkletnov's work. Definitely worth
keeping an eye on.
\_ "yeah, who needs a Nobel Prize, I'll just advance the frontiers
of science by screwing around in my garage." The guy's an
obvious crackpot. -tom
\_ You might want to listen to Act III from This American Life:
http://www.thislife.org/pages/descriptions/05/293.html |
| 2005/9/22-23 [Science/Physics] UID:39827 Activity:high |
9/22 What are the downsides to using a nuclear bomb to disperse forming
Islamic extremists? I'm pretty sure the cost of the bomb would be
offset by the money saved in devastation (100+ billion in a major city
anyone?).
\_ 9/23 reply: http://news.yahoo.com/s/ap/rita_wishful_thinking
\_ if you use a neutron bomb, nothing (well other than a bunch of
annoying anti-bomb peacenicks protesting in the streets and
annoying anti-bomb peaceniks protesting in the streets and
making the morning commute that much worse)
\_ Does the US even possess neutron weapons anymore? I thought
those were only deployed for a brief time during the '80s as
a buffer against a Russian tank invasion of Europe?
\_ Possibly. They have a short shelf life, and we aren't
making anymore AFAIK. We might be refurbishing them
though.
\_ Do you really think the government is dumb enough to
get rid of something like the neutron bomb (regardless
of what the official peacenik friendly story is)?
\_ Do you really think the government is dumb enough to get
rid of something like the neutron bomb (the official
story is probably just a cover to keep the peaceniks
happy)
\_ Assuming this is a serious question, (a) the islamic extremists
that threaten anyone don't "form" per se, (b) we'd blow up a lot
of innocent people and their infrastructure which we're at least
not supposed to do, (c) we have always had a policy since the end
of WWII of never using nukes first, and (d) nobody would ever ever
talk to the US again. Go sit in a corner. -John
\_ re (b), best reason to use a neutron bomb, the infrastructure
remains intact, some collateral human damage will occur, but
in war that can't be helped.
re (c), the no first strike policy has been "reviewed" by the
current admin and may be rescinded if the situation was dire
enough - therefore this policy is presently not a barrier to
the use of "nucular" weapons
re (d), the US is not well liked overseas, it is not likely
that further degradation of international opinion is a major
concern to the decision makers - armed retaliation may be a
concern but currently no nation can field a force sufficient
to make retaliation a sufficient threat to avoid first strike.
\_ neutron bombs are still atomic bombs ; they are just optimized
for radiation output vs. explosive blast power. If you want
to kill people and not infrastructure biological and chemical
weapons are the way to go. There's significant political
costs to their use, however...
\_ As opposed to less significant costs for normal atomic
bombs? |
| 2005/8/21-22 [Science/Electric, Science/Physics] UID:39208 Activity:nil |
8/20 http://www.scienceblog.com/light.html Ok can some physics person explain this: "the light signal travelled faster than 300 million meters a second. And even though this seems to violate all sorts of cherished physical assumptions, Einstein needn't move over -- relativity isn't called into question, because only a portion of the signal is affected" \_ Speed is length traveled over time taken. The trouble is, length traveled of a set of particles isn't a precise interval, but a 'smear' due to quantum effects. So some particles traveled a little more and some a little less. If the length traveled is very short, these sorts of 'smear' effects become significant. Actually, the way I understand it, the particles that finish 'a little after the finish line' also started 'a little after the start line', except we had no measurements of this. So each particle is still traveling at c. But this is a 'sane interpretation' where things have positions. -- ilyas |
| 2005/8/20-22 [Science/Physics] UID:39203 Activity:nil |
8/19 [ Thread deleted out of frustration. I can't seem to explain my
own question, so people just show up to chew the fat about QM.
Not a single person gave me an account of what an 'observation'
exactly is. I know what the slit experiment is. I know what all
the conventional interpretations of QM say. Doesn't it bother anybody
that the standard interpretation of QM is based on an apparently
undefined notion? ] -- ilyas
\_ Re last sentence - it bothers/has bothered lots of people (including
Bohr and Einstein). You may wish to see:
http://www.math.rutgers.edu/~oldstein/papers/qts/qts.html
http://www.mtnmath.com/faq/meas-qm.html
http://plato.stanford.edu/entries/qt-measurement
[ and many others, you can google as well as I can ]
\_ Also be aware that attempts to reconcile microscopic notions
with the macroscopic world have plagued physicists for a long
time. It boggles our minds that certain particles can be in
many states at once. So does the wave-particle duality and some
other issues. I think this field is still very young and a lot
more will be learned and the model will be refined.
\_ I think an important point is that the field is also
*experimentally* young. The number of physical systems in which
quantum mechanical entanglement, decoherence, etc. are being
tested is growing very rapidly (thanks to the fact that the NSA
is willing to throw hundreds of millions of dollars at quantum
computing.) |
| 2005/8/19-20 [Science/Physics] UID:39194 Activity:high |
8/19 Anybody who knows any physics, what's the deal with QM being based
on the notion of an 'observer?' Does anybody understand what an
'observer' means in QM context? I mean of course the standard
interpretation of QM usually taught. -- ilyas
\_ Once you *know* the cat is in the box, the cat can't not be in
the box.
\_ all of modern science builds models with a latent component and
an observable component. QM isn't "based" on an observed. Its models
just follow the latent-observable dichotomy. It's healthy. There
are things you see, and things you want to know.
\_ As I understand it under the most widely accepted interpretation
of QM, the Bohr-Heisenberg Copenhagen Interpretation, the state
of an atom is indeterminate prior to observation. Note that CI
is not the only interpretation of QM (some others I've heard of
are the hidden variables theory, the many-worlds theory and
decoherence)
\_ It's a probability function and where on the function the
atom is can only be known when you observe it. By observing
it you "give" it a state.
\_ The problem, as I understand it, is that you can only
give something a state via observation if that thing
is in a closed system. However, no such system exists
anywhere in the universe.
Also the implication of CI is that w/o some sort of
observers the universe does not "exist" other than
as a superposition of all possible states. Many,
including Einstein, felt that this cannot possibly
be true. [ Note I am not a physicist, I've mostly on
read about this stuff in Lectures on Physics, &c. ]
\_ At a basic level you can't observe a system without changing it.
You need to affect its state in some way to make a measurement. An
'observation' is really no different from plain old interference.
To take the Shrodinger's cat example, observation is information,
aka. photons leaving the box, and prior to that any internal state
was possible.
\_ I don't mean to be rude, but I don't think what you posted is
really answering my question. -- ilyas
\_ So what exactly changed that allows me to see a live cat?
Why would a camera (or a robot) not see a live cat? -- ilyas
\_ Because now the box can't not have a live cat.
\_ You don't seem to understand my problem. Why am I an
observer, but a camera, or a robot, or a robot that looks
and acts exactly like me isn't an observer? What is an
'observer'? -- ilyas
\_ Anything that alters the internal state of the box by
letting photons out of it is an observer. So a robot
which opens the box and snaps a picture would cause the
cat to assume a single state. However if you set up
the experiment with a camera on a timer inside the box
then until something external observes/changes the box
both the cat and the image on the film are in an
indeterminate state. -pp
\_ But what if the robot himself is also in another
bigger box? Shouldn't the state of the at now be
entangled with the state of the robot? I can setup
lots of boxes like one of those russian Matryoshka
dolls -- at what point does the state of the cat
get settled? -- ilyas
\_ In any given problem you're applying QM to you define
something to be your "system". In real life it's
probably an atom or something, but in the cat example
it's generally assumed to be the box and the cat
together. An "observer" can be anything from the rest
of the universe interacting with the system. So it's
a bit arbitrary. I think the point is, though, that
you always draw the line between observer and system
between *you* and your experiment somewhere. Another
observer could put you in the "system" box and say
the same things about your quantum state that you can
about some cat in a box. So to I think answer your
question, in the interpretation of QM I was tought
the concept of observer has nothing to do with sentience.
the concept of observer has nothing to do with
sentience.
Of course, since you've already classified my brain
as:small, you might want to ignore what I have to say.
\_ The camera doesn't make an observation. Until you
view the film the state of the film is indeterminate -
the film could be in any valid state. Only when you
view the film does its wave function collapse into
a particular state.
In order for any of this to make sense the observer
must be outside the closed system that is observed.
HOWEVER, there is no such thing as a closed system
w/in the universe.
\_ So to summarize, there is no closed system in the
Universe. So while in Schrodinger's hypothetical
experiment the cat's state gets settled, it would
not get settled in ours. So does the collapse
phenomenon exist or not? -- ilyas
\_ http://www.fishnet.co.nz/ted/murph/wpd.html#BM2Slit
In the wave model, much significance is often attached to the
idea that determining the position of a particle close to the
slits "destroys" the "interference" because the "wave function
collapses".
If you measure the position of the electron just before it gets
to the slit, you totally change the outcome of the experiment.
A simple and elegant way of proving that the observer is part
of the experiment. I will try to find a cleaner explaination
of this phenomena. -ausman
http://www.daviddarling.info/works/ZenPhysics/ZenPhysics_ch10.html |
| 2005/8/19-22 [Science/Biology, Science/Physics] UID:39188 Activity:moderate |
8/19 Hey Emarkp. Re: Religion. Please prove that there is God. For
extra credit prove Joseph Smith was telling the truth.
\_ Someone deleted this along with a post about ID. I'll note that I'm
not presenting God or Joseph Smith as a falsifiable scientific
theory. ID proponents /are/ claiming their theory as science.
-emarkp
\_ We had a long discussion about this already. In the narrow
sense of
\_ Please prove there is no god. For extra credit prove Joseph Smith
was not telling the truth.
\_ The burden of proof is on someone who claims God exists. (Just
like the burden of proof of evolution being on someone who claims
evolution is real.)
\_ Absence of proof is not proof of absence ;-)
\_ yup, Rumsfeld can tell you that it worked well with
Iraq.
\_ You are confusing a syntactic distinction with a semantic one.
You seem to be saying that existence statements are 'special'
and require more proof than their negations. But almost
anything can be phrased as an existence statement (e.g.
there exists a sequence of physical events giving rise to
a bacterium while starting from raw chemicals).
\_ What about "One can't prove a negative."?
\_ I don't understand what this means. In mathematics,
as in empirical science, 'a negative' is just a
syntactic distinction. In math what you can prove
usually has little relation to its syntactic form.
In empirical science you can prove nothing.
\_ Apparently you flunked Science. The central tenet
of science is that if you can't empirically prove
that it does exist, we will assume that it
doesn't. Science has traditionally followed
such principals as Occam's Razor, in which
the simplist explanation (we assume that
things do not exist until they are empirically
proven to be as such) is usually the most
\_ Uh no, science says that if something cannot be
empirically proven, it means that it cannot be
empirically proven. Whether that implies "yet" or
"at all" is up to the observer. Last I checked,
science made allowance for, say, circumstantial or
observational evidence not obtained through proper
empirical experimentation, even though you wouldn't
necessarily rely on these as proof. Note that I'm
not implying that ID and friends are complete and
not implying that ID and friends aren't complete,
utter intellectually dishonest bunkum, I would
just like to point out the flaw here. -John
likeliest. Also, in science, it's not merely
a syntactic distinction, that's why it's referred
to as empirical science vs. religious wizardry.
And math != science, because yes, math IS
pure syntatics.
\_ 'Empirically prove'? 'Pure syntatics?'
'Simplist'? 'Likeliest'? You such at science,
you suck at English, you suck at trolling, and you
suck at life.
\_ Since Science can't explain the change from
"nothing" to "something" in the universe should
we assume that Science doesn't exist or that
the universe doesn't exist? Please explain
further. ;-)
\_ Science CAN explain how the universe could
have come from nothing:
http://curious.astro.cornell.edu/question.php?number=541
\_ Nonsense. Did you even read your own link?
It not only doesn't attempt to explain how
the universe was created. It makes it
quite clear that we have no idea and
presents a bunch of ideas that don't rise
above the level of hypothesis. These
non-explanations are no better than "God
did it" or "it fell out of a magic hat with
a rabbit". By the standards mentioned
earlier in this thread not only does
science not exist, but the universe doesn't
either. Your link (that you apparently
didn't read or expected others not to) says
something entirely different from what you
claim it says.
\_ Alexander Vilenkin (mentioned in the
link above) has written many papers
about this. You can google for more
detailed info.
\_ Well the universe does exist to
science since we observe it.
\_ http://www.yfiles.com/y3nf.html |
| 2005/8/16-20 [Politics/Domestic/911, Science/Physics] UID:39143 Activity:nil |
8/16 Once again, the onion news story sounds no sillier than the reality:
http://www.theonion.com/news/index.php?issue=4133&n=2
"Even critics of Intelligent Falling admit that Einstein's ideas about
gravity are mathematically irreconcilable with quantum mechanics. This
fact, Intelligent Falling proponents say, proves that gravity is a
theory in crisis."
\_ The differential equation on the screen is awesome.
\_ What does it read? It's too small for me.
\_ dx/dt = 1 Cor. 1:10
\_ Sweet...
\_ Haha! This shows how silly the Evangelical "scientists"
are. Gravity is related to acceleration, which is dv/dt
not dx/dt.
Oh shit! I forgot that this is The Onion!
\_ tom's axiom 1
\_ What Newton said, in his own words:
http://en.wikipedia.org/wiki/Gravity#Newton.27s_reservations
\_ Makes sense to me. That's why people say he came up with the
"law of gravity" versus "a theory of gravity". Not saying that
a theory is a full explanation, but at least it's more in that
direction. |
| 2005/8/9-13 [Science/Physics, Science/Biology] UID:39076 Activity:moderate |
8/9 http://www.creators.com/opinion_show.cfm?columnsName=pub \_ this link doesn't work anymore I haven't been paying attention to the ID vs. Evolution discussion but I read this in the Merc and I was a bit surprised by the arguments made in favor of ID. Do the ID folks really think that the universe has more order now than at some point in the past when all the forces were unified (more entropy/disorder now right?) Also I'm confused by the assertion that the laws of nature imply ID. Isn't is equally plausible that the laws of nature are the result of (1) random chance or (2) the result of a natural process (such as collisions of branes in higher dimensional space) that creates an infinite number of universes so all possible laws of physics are expressed? \_ Well, I don't know about most of the arguments presented, but it is a little puzzling that the fundamental constants would arrange themselves randomly into an interesting looking universe that we have. If things were a little off, the universe would be it is a little puzzling that the fundamental constants would arrange themselves randomly into an interesting looking universe that we have. If things were a little off, the universe would be very boring indeed. -- ilyas \_ But there is a small but finite probability that the came about by random chance right? And by boring you mean boring to people right? Some other arrangement might give rise to a universe that is interesting to different form of "life". What I don't understand about ID is that there does not appear to be a way to show that ID is more likely than the theory that branes are/have been colliding in higher dimensional space for an infinite amt of time thus making possible every arrangement of the fundamental constants. How can one accept a theory which is by definition un- proveable? \_ By 'boring' I mean you can't have life as we understand it -- low entropy entities that use energy to maintain their state, or for that matter planets, stars and galaxies -- things needed to support life. -- ilyas \_ http://en.wikipedia.org/wiki/Anthropic_principle \_ The only way we can even talk about this is if we happen to have the conditions for life. So, just out luck that we happen to have these conditions, however small the chance. It really doesn't prove anything. \_ And this is called the "weak anthropic" principle. For some strange reason, I can't find anything in ID addressing it (which I'd think would be important). -emarkp \_ You don't understand. This isn't meant to be a proof of anything, but something requiring an explanation. -- ilyas \_ The point you're missing is that if there are an infinite number of universes, only in the ones where the physical laws are conducive to the rise of intelligent life will there ever be anyone to notice that the physical laws are conducive to the rise of intelligent life. -tom \_ And what if there isn't an infinite number of universes? Occam's razor says to assume the least. Why is it more 'expensive' to assume intelligent design than to assume infinitely many universes? -- ilyas \_ Because intelligent design still presupposes a creator, which just pushes the question up a level; who created the creator? It's a lot easier to assume an infinitude of universes than to assume that an intelligent being somehow sprang into existence before the universe did. -tom \_ So you would rather postulate an infinitude of worlds than suspend for a moment your intuitions borne of your linear perception of time? Seems like people suspend intuitions a lot when looking at fundamental things -- consider quantum mechanics. I should mention that 'created' is a causal notion, and causality is an illusion, a way our brain organizes information. There is no causality in physics. -- ilyas 'created' is a causal notion, and causality is an illusion, a way our brain organizes information. There is no causality in physics. -- ilyas \_ Wikipedia on "Causality (physics)": "special relativity has shown that it is not only impossible to influence the past" "Despite these subtleties, causality remains an important and valid concept in physical theories." \_ This is one of those cases where I know more about the subject matter than wikipedia. There is no causality in physics, only in physicists. The standing of causality in modern physics is so weak that even my advisor, a fairly influential causality guy, concedes that it's all likely an artifact of the human brain, and not an objective feature of reality. On a slightly unrelated note, I wish people would stop quoting wikipedia as an authoritative source. I read some of their 'contention' pages, and wasn't really impressed. You don't have to look far to find wikipedia blatantly being wrong -- in the general Causality article, Pearl and Spirtes are listed under 'Probabilistic Causality,' which is untrue, proponents of that area include Good, Cartwright, etc. Pearl/Spirtes are in 'Structural Causality.' Wikipedia is trash. -- ilyas the human brain, and not an objective feature of reality. On a slightly unrelated note, I wish people would stop quoting wikipedia as an authoritative source. I read some of their 'contention' pages, and wasn't really impressed. You don't have to look far to find wikipedia blatantly being wrong -- in the general Causality article, Pearl and Spirtes are listed under 'Probabilistic Causality,' which is untrue, proponents of that area include Good, Cartwright, etc. Pearl/Spirtes are in 'Structural Causality.' Wikipedia is trash. -- ilyas \_ I support quoting of Wikipedia as an authoritative source, with disagreements with Wikipedia well disagreements with Wikipedia documented on motd for any sodan to evaluate. -jctwu to evaluate. Wikipedia's usefulness significantly outweighs its negatives when used in this way. -jctwu \_ What usefulness? It's an encyclopedia and it's WRONG. A lot. Do you really want me to look through the causality article and list all things it got wrong? Wikipedia's 'usefulness' is misleading people into thinking they know something. -- ilyas \_ Then fix it man -- you're extremely lucid in your writing when you set your mind to it. That's one of the nice things about Wikipedia -- I assume that people with brains and enough confidence in their knowledge go in and remove blatant inaccuracies, so as time goes on, the overall quality of the information gets better. Don't get me wrong -- it's still a source of info which resides in the internet and therefore is deserving of a little skepticism, but it's still a damned handy reference. -mice \_ It's a Wiki-based encyclopedia, not a traditional encyclopedia. In your opinion, Wikipedia is trash; I already stated my opinion. You could also submit a change, but that's your prerogative whether you do or do not and why you wouldn't. I don't think we can get any farther than this. any farther on this. One more thing you can do: We can avoid the subjective question of whether Wikipedia is useful or not, and you can instead explain calmly and succinctly why there is no causality in physics, and/or post a URL which says so. Pretend you're Feynman lecturing to a freshman physics class. -jctwu \_ This logic appeals to me, but many find it deficient. Of course, if things weren't conducive to us being here, we wouldn't be here.... Those who have the most trouble with this usually cite the incredible odds against it. However, with possibly a trillion "trial" locations, over a span of billions of years, it doesn't seem unlikely to me that life would somewhere arise and ponder the unlikelyhood of it all.... But the pondering would 100% take place in those lucky, rare locations that "won". Like here. \-there is a good paper that assess the amount of "tolerance" we can have in various "free parameters" [i.e. the fundamental physical constants] in light of the anthropomorphic principle [the idea that we have to be here to to ask the questions] ... i can dig up the reference if there is interest. if you are interested in this you may want to review first review the list of free parameters ... some of them are pretty technical but you need some knowledge of what the are to see how things fit in terms of "dependencies". there are many good discussions of this. \_ Who says there are "trials" or they take any "time"? Why not "every possible existence that could be, is"? And maybe that means there are an infinite number of existences, and maybe that means there are a finite but greater than one number and maybe that means this is it and the only it. It's all just freshman lounge chat anyway since we can't ever know but this is better than a lot of the other motd/wall posts. \_ Hey ilyas, tell us about the stars. -aspo \_ Aspolito is a meme's way of making another meme. -- ilyas \_ ID is intellectual fraud. It presents strawman arguments about evolution and largely consists of handwaving. I can't distinguish between it and more sophisticated moon-hoaxers. -emarkp \_ Do other religious conservatives give you a lot of shit for being such a decent, rational person on science issues? I think it's fantastic to see someone who self identifies as a religious conservative speak out against these people. You can probably get a lot more traction stopping them from destroying American science than us liberal jewish athiest scientists. can probably get a lot more traction stopping them from destroying American science than us liberal jewish athiest scientists. \_ I've never been criticized for it. I point it out misrepresentations of science when I see them, and misrepresentations of religion when I see /them/. I'm particularly annoyed about ID because it is an attempt to misrepresent science to defend the author of physical law, and I just read a 30-page article this weekend from ID that read like an anti-religion tract but was basically anti-Evolution. -emarkp \_ ID isn't really about the universe and physical laws, but more about: Goddamn, can you believe a tiny sperm and a tiny egg can combine and grow into one new human being, without anything else going wrong? GAWD or ALIENS must have been involved! \- a fairly cool book on weird examples and corner cases in biology is THE DIVERSITY OF LIFE by EO WILSON. I found this quite readable and interesting and I have a fairly limited bio background. http://csua.org/u/czi \_ Cf. a good deal of Stephen Jay Gould's work on evolution. \- isnt SJG soft on ID? \_ No. Read Bully for Brontosaurus. \- Some comments: the ID vs Evolution debate is somewhat interesting for various reasons but it mainly has to do with politics when hitting a low [like BUSH weighing in about it] or philosophy of science [what is a theory vs a collection of fact, what are standards of proof, causality in an empirical or observational science]. if you are interested in actual debates on evolution, those dont really concern the teleological or "invisible hand" aspect of ID but other "legitimate" issues with the various competing evolution theories. dawkins and gould are the populerizers, but you can also look at wilson, mayr [died recently too], this fellow H. Orr, Stevene Pinker, matt ridley, and r lewontin [recently gave a talk at berkeley] and daniel dennet. a lot of these guys have secondary agendas and strong personalities so it makes for an interesting story/debate to follow. \_ The problems with ID are twofold: 1) It is not science, it is philosophy. Don't teach philosophy in science classes. And 2) As soon as you use the "The Wizard Did It" type of logic to explain the world then it's religion, not knowledge, and you can go to church to become indoctrinated in such a fashion. |
| 2005/7/18-19 [Science/Physics, Science/GlobalWarming] UID:38679 Activity:nil |
7/18 More "cold" fusion results:
http://news.uns.purdue.edu/UNS/html4ever/2005/050712.Xu.fusion.html
\_ So, this could possibly produce net energy gain?
\_ A different article I read on this quite some time ago said no
way, it was only interesting in a theoretical sense.
\_ That's cool, I'm all for improving our understanding of
fusion. It just that the article is half about how
fusion is going to solve all of our energy problems.
\_ [elevated]
\_ Someone posted on 4/27:
http://www.nature.com/news/2005/050425/full/050425-3.html |
| 2005/7/13-14 [Recreation/Dating, Science/Physics] UID:38592 Activity:high |
7/13 Color footage of Einstein:
http://www.ifilm.com/ifilmdetail/2673351
\_ obJewBaiting.
\_ The bastard is smart but is still a bastard. "His letters reveal a
tumultuous personal life, married twice and indifferent toward his
children while obsessed with physics. Yet he charmed lovers and
admirers with poetry and sailboat outings." What as ASSHOLE.
I guess you can say that he's extremely brilliant and contributed
greatly to mankind. He's also extremely horny and takes little
responsibility for women he fucks and children he created.
http://iml.jou.ufl.edu/Newszine/health_science/5.html
http://www.foxnews.com/story/0,2933,153696,00.html
\_ Hey asshole. Why do you keep deleting all replies to your
frothing?
\_ I didn't delete them, I just unintentionally overwritten
them since I don't use motdedit or vi
\_ I didn't kill him, I just shot him in the head. Blame
the bullet.
\_ I think this kind of defense are actually used in
manslughter trials, sadly.
\-FYI: one of einstein's children operated out of ucbberkeley
\_ Frank Lloyd Wright did many of the same things: ignored
children, had mistresses, obsessed with his work. Are there
examples of geniuses who were consummate family men?
\_ Yes, but FLW wasn't a Jew, which I suspect is what is really
clamping froth-boy's nipples.
\_ Pablo Picasso was never called an asshole.
Not like you.
\_ is that a punk rock reference? you're so cool!
\_ It is much cooler to accuse someone of anti-semitism
on the basis of absolutely no evidence.
\- there is a somewhat famous example in moral
philosophy that looks at paul gaugain chosen
by bernard williams [now dead but formerly
ucb phil] on this point ... "does success excuse
not honoring some claims people have on you".
\_ iirc, Euler was a family man (twice married) but took care
of his kids, grandkids, &c.
Other examples from the top of my head: Bohr, Feynman,
Jefferson (and don't give me that crap about Jefferson's
slave kids, DNA testing shows that Jefferson's brother
was most likely the parent of the slave kids - Jefferson
gave his word to his wife when she died that there would
be no other women and Jefferson kept it).
Re Einstein - Two points:
(1) He is not a bastard as his parents were married at the
time of his birth.
(2) Even assuming the colloquial meaning of "bad person",
Einstein does not qualify. He may have been a distant
or less than ideal father (many non-genius fathers
fall into this category) but he never really neglected
his children. For example, he provided Mileva (wife 1)
and the children w/ all the money from his Nobel
prize. Also, he was basically separated from Mileva
when he started seeing Elza (wife 2). There is some
evid that he saw women on the side some years after
he married Elza but there is no proof that he fathered
any children w/ them (or that he dated anyone other
than Elza during his marriage).
\_ meh
\_ There was color movie back in 1943?
\_ Ever seen Wizard of Oz?
\_ This reminds me of the Calvin and Hobbes where Calvin asks his
dad why old photos are always in black and white. |
| 2005/5/26-27 [Science/Physics] UID:37845 Activity:low |
5/26 LED capable of emitting exactly one photon each time:
http://www.newscientist.com/article.ns?id=dn7420
\_ Two questions: 1) The idea is that the receiver will know that a
message is intercepted because a photon can only be received by
either the interceptor or the receiver, not both. But what if the
intercepter then injects a different photon with the same wavelength
back to the stream right away? Then the receiver won't notice,
right? 2) Regardless of #1, isn't it more important to prevent a
message from being intercepted, than to know that the message has
been intercepted after it happens? It doesn't help much to find out
that someone has intercepted your SSN when it is transmitted this
way.
\_For quantum criptography you need a PAIR of coupled particles,
one for the sender and one for the reciever. Then both
sides make spin measurements on either the x & z axis randomly. By\
comparing a subset of those measurements you can determine if some-\
one was listening in. The rest is used for a key. -scottyg
\_ You don't send your SSN that way, you send a random string of
bits over the quantum channel, throw away the ones that get
read by the evesdropper, and use the remaining bits as the key
to a one time pad that you use to send the SSN over a classical
channel.
\_ This answers #2, thanks. What about #1?
\_ Not an expert, but wouldn't there be a machine-perceptible
delay as the intercepting device receives the photon and stores
its identifying info, then recalibrates and sends a different
photon with the same wavelength to the originally designated
receiving end? |
| 2005/4/28-30 [Science/Physics, Computer/Theory] UID:37415 Activity:nil |
04/28 Quantum Crypto for Video Conferencing:
http://www.nature.com/news/2005/050425/full/050425-9.html
\_ I think you don't need to crack every frame to steal secrets. If
you can crack the audio stream and you can crack one video frame per
two or three seconds, that's good enough. |
| 2005/4/28-30 [Recreation/Dating, Science/Physics] UID:37408 Activity:nil |
4/28 I'm surprised this hasn't been posted yet. Husband and Wife physics
professors fillibuster Frist: http://mcdfa.org/?q=frist2
I recognize that Griffiths book from Physics h7a!
\- Do you know who Ed Witten is? |
| 2005/4/27-28 [Science/GlobalWarming, Science/Physics] UID:37385 Activity:nil |
04/27 Desktop fusion
http://www.nature.com/news/2005/050425/full/050425-3.html |
| 2005/3/14-15 [Science/Physics, Politics/Foreign/Europe] UID:36681 Activity:moderate |
3/14 Why Mormons shouldn't move to UK:
http://news.bbc.co.uk/2/hi/science/nature/4341693.stm
\_ What the hell does any of that have to do with mormonism? Or even
religion at all? Huh?
\_ Hi troll! -emarkp (I had more Physics and Math than just about
anyone else I knew in the CS major.)
\_ yes, and the war in Iraq is the right decision, and Bush is
right, and everyone who thinks otherwise will go to hell.
\_ Woohoo! You win the stupidest troll of the day award!
\_ I don't think that's possible, given the guy below. -tom
\_ I assume you mean those 2 in the gay marriage
thread? Yeah, I wrote this before those were
posted. Maybe we need to take a vote.
\_ Tom's a fag, he's obviously biased.
\_ Wow, didn't know the "rightness" of the war in Iraq was
scientifically measurable. And no, I don't make pronouncments
about a person's eternal soul based on their politics.
about a person's eternal progression based on their politics.
Oh and sign your name. -emarkp
\_ I'd rather be a mormon than a fag.
\_ is that because you are mormon?
\_ You misspelled "moron"
\_ Why, exactly? And why have you given this thought?
\_ Well, I'll just throw gasoline on the troll fire and comment
that the two aren't mutually exclusive. -emarkp
\_ Uh oh. I don't think your metaphors are rowing with a
full deck of marbles. |
| 2005/3/10 [Science/GlobalWarming, Science/Physics] UID:36632 Activity:nil |
3/10 Berkeley physicist Charles Townes wins Templeton prize for "advancing
knowledge in spiritual matters". News link:
http://www.physorg.com/news3317.html and here's a link to the
essay that is primarily responsible for him winning the prize:
http://www.science-spirit.org/articles/Articledetail.cfm?article_ID=13
The subject of the relationship between science and religion has come
up a few times on the motd, so this seems relevant. |
| 2005/3/8-9 [Science/GlobalWarming, Science/Physics] UID:36575 Activity:nil |
3/8 RIP Hans Bethe
http://www.indystar.com/articles/9/227610-2979-010.html |
| 2005/2/25 [Science/Physics] UID:36423 Activity:very high |
2/25 Is anti-matter and dark matter the same thing? Thx.
\_ Is our children learning?
\_ No they ain't. As to original question, not at all.
\_ No, you're wrong. Technically speaking dark-matter could
be the "same" as anti-matter if it turns out to be
composed of neutrinos. Since neutrinos are their own
anti-particle you could say that dark matter is composed
of anti-matter. Right now we don't know what dark matter
is. Perhaps it could be composed primarily of some sort
of anti-matter. Nobody knows.
\_ "More seldom than not, the movies gives us exquisite sex and
wholesome violence, that underscores our values. Every two
child did. I will."
\_ http://en.wikipedia.org/wiki/Antimatter
http://en.wikipedia.org/wiki/Dark_matter
\_ Dark matter is quite different from normal baryonic matter
and anti-matter. There are several views on what exactly
anti-matter is, but in general it can be though of as
matter that is composed of particles that are similar to
protons and electrons except that they have the opposite
charge (ex. positron is an electron with a + charge).
Dark matter is completely different. It interacts with
regular matter very weakly and is probably not composed
of any sort of known particles. Dark matter's presence
is mostly inferred from gravitational anomalies in the
rotation of galaxies. Some newer experiments are trying
to detect dark matter based on nuclear interactions, but
so far nothing has turned up.
\_ There was some /. story recently on something that looks like
an entire galaxy composed entirely of dark matter. Dark matter
has a bit of a 'magic blue smoke' quality to it, imo. -- ilyas
\_ I agree. The entire dark-matter/dark-energy discussion
reminds me a lot about the cosmic ether discussions prior
to SR. It seems like the universe is telling us something
fundamental and physicists want to shoe-horn it into the
standard model.
BTW, how did they detect a dark matter galaxy?
\_ I am not a specialist, so I don't know (the article didn't
really explain it well). Obviously using some indirect
way involving gravity, coupled with noticing there are no
stars there. -- ilyas
\_ If you are talking about the recent results re
VIRGOHI21, my understanding is that it was a
radio telescope search looking for H emission
lines. Also this isn't a dark matter galaxy
but a dark galaxy (basically a huge cloud of
H w/o many stars).
\_ I would be very surprised if you could get a cloud of
H to behave like a galaxy without any star formation.
-- ilyas
\_ How much dark matter is in a liter of the air next to you?
If none, how much dark matter is there in a liter of volume
of deep space?
If negligible, about how much volume of deep space would you
need to get one particle of dark matter?
\_ IIRC current estimates are that each second every square
meter of the earth passes through 1e9 dark matter particles.
\_ That means 1 liter has ~ one million dark matter particles!
I am swimming in dark matter!
\_ In comparison a liter of water has ~ 1e25 water
molecules.
\_ If we take 1 liter of air, I'm getting ~ 4 particles
of dark matter for every trillion molecules of
air. Is that right?
\_ Sort of. Dark matter is "there" but it doesn't
interact w/ regular matter. It just passes
through your body (and pretty much everything
else) as if it wasn't even there.
\_ Hmmm, so the motd is dark-matter. If we put ilyas and tom
together, would they explode?
\_ I think that you are confusing a few concepts. Dark
matter is weakly interacting and does not affect
normal matter except via its gravitation effect.
The following works a bit better: the motd is space-time,
ilyas is matter, tom is anti-matter. If they both
meet on the motd you will get an uncontrollable burst
of energy that will destroys everything in its path.
\_ If the only way to detect dark matter so far is from gravitational
anomalies, how do they know that dark matter is in the form of
discrete particles (or wave-particles like the way normal particles
are in quantum physics)?
\_ If you really want to know, look online in a source that does
not consist of computer science people. There is much
bullshit in the above answers, and I have become tired of
having flamewars with morons on the motd about physics.
Look on the websites of the various darkmatter searches out
there, and they should have good explanations of what they're
looking for and why.
\_ is dark matter like the Force?
\_ Not everyone agrees that dark matter is made of particles.
The leading theory is from the super-symmetry people who
think that one of the particles in their theory, the
neutralino, fits the dark matter bill.
FYI, SciAm had some decent articles on this topic a few
months back. |
| 2004/11/18 [Science/Physics] UID:34950 Activity:low |
11/17 SICP for physics: http://mitpress.mit.edu/sicm \_ drool. thank you. \_ OMG this rocks! Thank you. |
| 2004/10/9-11 [Science/GlobalWarming, Science/Physics] UID:34011 Activity:nil |
10/9 Regarding that Dyson dude on TV with the vacuum that doesn't lose
suction- what's the technology that keeps the dirt away from the
filter?
\_ Well I wrote a well thought-out reply but some douchebag overwrote
it. I was sort of right in that there can be no bag and that
airflow causing the dust to settle might be the mechanism. A little
googling produced:
http://workingfromhome.allinfoabout.com/dyson_pt4.html
So the airflow is designed to increase centrifugal force and stick
the dirt to the side of the cannister. |
| 2004/10/4-6 [Reference/Military, Science/Physics] UID:33922 Activity:high |
10/4 Photon Torpedos anyone?
http://tinyurl.com/62nk9 (sfgate.com)
\_ A photon is not matter. However, they *have* used antimatter
weapons in trek.
\_ m = E / c^2 :-)
\_ No, a photon has no mass. You just gave the mass-equivalence
of a photon.
\_ Photon Torpedos are based on antimater:
http://www.ccdump.org/photontorps.html
http://www.cakes.mcmail.com/StarTrek/photontorpedo.htm
\_ Nothing will come from this for many decades, if ever. They should
be spending that money on something useful like the homeless or
universal health care.
\_ You can use the homeless as weapons? Cool!
\_ The article mentions positronium, but makes no mention of trying to
use antihydrogen. Is there some reason positronium is preferable?
\_ We have to catch up to the terrorists who are already building
anti-matter weapons out of unobtanium.
\_ Why do you hate America?
\_ Why is this conducted by the Air Force? Shouldn't it be the Dept of
Dept of Energy? Air Force should be working on better planes,
Energy in a Lawrence lab? Air Force should be working on better planes,
better missles, and maybe better space-based weapons, not working on
something that involves so much fundamental physics.
\_ The Air Force typically has always held sway over the "cutting
edge/whiz bang/star trek side" of military tech.
\_ no. I know of quite a bit of far-out physics research
that gets funded by both the Navy and the Army. The army
spends a lot of money on quantum computing, and you can't
get much more star trek than that.
\_ My computer told me otherwise this morning. It was built
by the USMC with Marine-Tech(tm). |
| 2004/9/29 [Science/GlobalWarming, Science/Physics] UID:33835 Activity:high |
9/29 What an embarrassment for Nature. The editors and Mann of global
warming fame are beginning to look very suspicious.
http://www.climate2003.com
http://www.uoguelph.ca/~rmckitri/research/fallupdate04/update.fall04.html
\_ The editors of Nature are known to be jackasses. Talk to anyone
who has been in any field of science at a high level for long
enough to have dealt with them, and they'll all tell you this.
And it's not just sour grapes. I know pleny of people who've
been published in Nature multiple times who think this. As far
as this stupid "dogleg plot" controversy goes, peer review is
only as good as the peers of the person who submits the paper.
Some fields have a lot of jackasses in them. Just for shits and
grins, you should go through the old copies of Nature from a
hundred years ago or more in the stacks of a university
library and see how nasty scientific controversies were back
then. Believe it or not, they were worse.
\_ Were there scientific controversies 100 years ago that were
used as evidence to promote the wholesale realignment of
global industrial policy?
\_ Yeah, there are some pretty horriable peer review stories out
there. We had a talk here at LLNL a month or so back about
using bad computer data in published papers. The peer review
process let a lot of really bad science pass. (Like, you can
see that this graph increases linearly! When investigated, it
turns out they only plotted 2 points. etc.)
\_ Are you a Republican?
\_ Why do you ask? Because only Republicans require good data to
base their decisions on? -!op
\_ There's no such thing as "good data". There's only bias.
Once you have determined your bias, then you pick the data
to support your bias, and you form your conclusion based
on your data.
\_ There is good data. Because of good data, bridges stay
up, airplanes fly, and the Internet doesn't grind to a
halt. Nature is not forgiving to bias. You should
maybe read up on this invention called
'empirical science.' (Yes, my sarcasm detector is in
the shop). -- ilyas
\_ There is good data and there is bad data. The data in the
seminal paper "Electron-Band Structure in Germanium, My
Ass" was bad data.
\_ And there is even worse than bad data, which is
cooked data. At least the E-BSiGMA paper accurately
plotted what he observed.
\_ I prefer my cooked data with gravy made from the
blood of the working man.
\_ Mm, one of my favorite recipes from "To Serve
Man." |
| 2004/9/21 [Science/Physics] UID:33680 Activity:nil |
9/21 [Iran nuke thread restored, completely]
Hi, I'm a completely unqualified dolt who has taken physics 7C and
I think Iran will have nuclear weapons in 24 months. What do you
guys think?
\_ I mean so what? We have nukes too. It's not like we are telling
them, oh, you can't have it because no one have it. We invented
WMD, we have the MOST WMD on earth, but sorry, you just can't have
it because we are the big boss.
\_ I think everybody should have nukes, this way, little Bush
can't go around fuck other countries. Go NK.
\_(Sarcastically) Oh, yeah, you are much smarter and wiser than
sanctioned members of the inspection team, therefore even though
they say it's gonna be one year you're completely right.
\_yeah, but I took 7C with professor Blugerblat, and he said
that it wasn't making a nuke that was a problem, it was
refining the stuff in it.
\_ Oh, you don't mean THE professor Blugerblat, do you? Oh my,
you MUST be an expert.
\_Well, I am, because A) I'm a liberal, B) I took physics 7C,
and C) I'm a disciple of Blugerblat. And the Hiroshima
bomb was never tested, nevermind that a bunch of existing
and future nobel laureates spent a couple years on
project Manhattan to develop the first atomic bomb,
because, goddamnit, I'm an expert because I took physics
7C. Did I mention I was a liberal and I took physics 7C?
\_ We've used up all our credibility on Iraq, that we can't do
anything to North Korea and Iran... and Pakistein (for helping out
Iran/N.Korea to develop nukes). Furthermore, this pre-emptive
strike doctrine really need some revision. United Nations just
released a report saying that 40 countries has the capability of
making nukes. The thought of invading more than 4-5 coutries
at the time is beyond my imagination.
\_ DON'T LET THE TERRORISTS WIN! RE-ELECT BUSH AND INVADE
40 COUNTRIES AT ONCE!!! |
| 2004/9/8 [Science/Physics, Politics] UID:33425 Activity:nil |
9/8 Resurrected:
\_ These are very different ideas. Belief in an
impersonal force which refrains from direct
interaction with the universe admits for the
possible existence of other metaphysical
constructs, such as an afterlife. If you deny
the existence of anything metaphysical, you are
stuck with just the physical.
\_ So you're just kind of hoping for an afterlife. No real
reasoning behind it. I guess my point is: what's the meaning
of this possible afterlife? It seems like people just project
the existential questions of this mortal life into this
afterlife, and that settles that. But what do you do in that
afterlife? And if you believe that the universe is running
purely on physics then your life is tied to the physical
processes of your body anyway (a soul is not physical).
Of course, evidence tells this anyway (physical changes
to the brain and brain chemistry directly affect people's
minds). Personally I think the human race has the theoretical
capacity to create "heaven" right here on Earth, and elsewhere.
We just aren't quite advanced enough, don't focus all our
energies toward it, and most of us complacently accept the
standard religious placebos that avoid the question. I like
to think that we ourselves collectively hold, in some measure,
the power of our own salvation. |
| 2004/8/30-31 [Science/Physics] UID:33238 Activity:high |
8/30 link:csua.org/u/8u5 This creates some problems for the modern interpretation of quantum mechanics. This is a very recent result: august 2004. -- ilyas \_ Ilyas, tell us about the...oh never mind. \_ OK what do we do now? \_ Well, presumably first we duplicate the results a couple of times to make sure it's right, and if they still hold, we chain some theoretical physicists to their chairs until they give a good interpretation of QM which fits this data. -- ilyas \_ http://www.kathryncramer.com/wblog/archives/000674.html \_ what the fuck ever. for those of us who don't get our science from blogs based on misunderstood crap, here's what 10 seconds of google turned up: http://www.newscientist.com/opinion/opletters.jsp?id=ns246010 basically various people debunking the article that the blogsphere scrambled and amplified. funny how Science and Nature missed out on this "earthshattering" discovery. \_ Hey idiot. Afshar is one of the bloggers. Fucknut. Another one is Kathryn's dad John, who you may have heard of. Jerk. \_ hi ilyas! glad to see you are still following the inverse of the golden rule! \_ Shahriar Afshar is obviously a Kerry supporter. Light, both a particle AND a wave, AND at the same time, too? Which is it, Afshar? You CAN'T have it both ways! \_ For those who are curious, the http://newscientist.com URL explains why Afshar is wrong. Thanks. No problems created. \_ Wasn't me. Try again. Incidentally, Afshar being wrong is _good_, not _bad_. I am just reporting an item of possible interest. -- ilyas \_ Oops. You had seemed pretty irritable lately, but not that much. \_ I really don't understand how these experiments are touted as showing the "dual nature" of light. Like any double experiment this demonstrates 1.) the WAVE nature of light and 2.) the fact that the detector detects in discreet quantities. There are equations for energy exchange between wave functions. Where is the need to resort to any "particle" nature? -phuqm |
| 2004/7/1-2 [Science/GlobalWarming, Science/Physics] UID:31108 Activity:very high |
7/1 Light might have been slower 2 billion yrs ago:
http://www.newscientist.com/news/news.jsp?id=ns99996092
\_ Just in case you don't know, http://newscientist.com is about as reliable
a source for science news as *name-of-random-tabloid* for news.
\_ any better sources?
\_ <DEAD>sciencenews.org<DEAD>, and <DEAD>physicstoday.org<DEAD> for physics.
There must be others, but be warned that they are
all boring: the more reliable the more boring.
More generally, science != news != entertainment.
\_ Uh, Nature? Departmental hearsay? Anything? -- ilyas
\_ Just by reading the article, I have no clue whether it's real or
fake. Are you saying that the article is a hoax, or it's just
flawed science? |
| 2004/6/17 [Science/Physics] UID:30871 Activity:nil |
6/17 Atoms teleported:
http://biz.yahoo.com/ft/040616/1087373056034_1.html |
| 2004/3/18 [Science/GlobalWarming, Science/Physics] UID:12743 Activity:nil |
3/18 I love this. What do we do when we found out Pakistan was selling
nuclear technology to N.Korea, and other so-called "rogue nation?"
We forgave 480 million USD of debt. How ironic we actually invade
Iraq for the same reason. Moral of the story? This is not about
WMD, it's about being on the good side of USA.
\_ Well duh, we're the good guys. |
| 2004/3/15 [Science/Physics] UID:12664 Activity:high |
3/15 Something for you Physics students
http://www.cs.wisc.edu/~kovar/hall.html -John
\_ so, are all you cs dudes "rolling in cash?" -physicsstudent |
| 2004/1/29 [Science/Physics] UID:12006 Activity:nil |
1/29 Fermionic condensate created:
http://tinyurl.com/2hjjb (news.yahoo.com)
\_ Fermions cannot form condensate. Bosons can. However, pairs of
fermions can become pseudoparticle bonsons and condense, which is
what happens in conventional superconductor. What they probably
achieved is cooling fermions so much that they fill up the fermi
levels from ground up (almost) one-by-one. (Look up phy 7C text.)
It's interesting stuff, although calling it fermionic condensate is
an intentional oxymoron and a PR exercise. Also, there are far
more known states of matter than listed in the above url.
\_ The same phenomenon happens whenever you make a superconductor.
Pairs of electrons act like bosons. The only special thing is
that they did it with bigger fermions than before.
\_ I think not. In conventional SC, fermions are bounded as
Cooper pair and not in their free states, but this is outside
the scope of motd.
\_ The valence (highest orbital) electrons form pairs and carry
the current. The lower-orbital electrons are bound.
http://physicsweb.org/article/world/15/4/7
http://www.physicstoday.com/vol-56/iss-10/pdf/vol52no10p17-18.pdf |
| 2003/12/4 [Science/Physics, Computer/Theory] UID:11308 Activity:nil |
12/3 Did anybody catch the Nova series on PBS a month or so ago on
String Theory? What do you think of it? Is this Witten guy really
that smart? He looks a bit phony.
\_ Dunno about string theory, but string practice: ~john/ringback.jpg
\_ Hot. Who's she?
\_ why the fuck do people keep talking about this goddamn show?
If you want to know about string theory, for some godforsaken
reason, read a fucking book.
\_ somepeople want a lay person's explanation to be done in
an hour. Books take much longer than that.
\_ How about http://staff.science.uva.nl/~rhd/string_theory.html
\_ I'll sum it up in two lines on the motd:
If a theory is unrelated to experiment, it's not
physics, it's philosophy.
for more information type "dict wank."
\_ Apparently you're a wank wannabe scientist who's never
read Kuhn. --williamc
\_ I heard there may be experiments with the potential
to falsify string theory coming after the CERN accelerator
comes online in 2006. -- ilyas
\_ right, and when they do, the theory will either
be falsified or just unverified. wake me when
they can calculate the mass on the electron from
frist principles or predict a new particle
acurately, or do *anything* predictive. <snore>
\_ We will eventually run out of things to predict.
A theory isn't good only if it predicts something new
(although that's really nice). A theory is good
if it doesn't contradict any data and is as small
as possible. Personally I know next to nothing
about string theory, and lack the background to
learn more. I don't know how well it fits, and
I don't know how small it is (or why there's so
\_ How about http://staff.science.uva.nl/~rhd/string_theory.html
much hype). -- ilyas
\_ wow, this is the first time i heard this show mentioned. i must
be out of it. anyway, go read Brian Greene's "The Elegant
Universe." it gets pretty dense as you get into it, but given
enough dedication, you can follow what he's writing.
\- the Witten/Schwartz/MGreen(not BGreene) is a pretty standard
serious work on string theory: http://csua.org/u/557
witten solved a problem a bunch of other people were
stuck on [i think this is descrived in vague terms in
the show, but i saw it a only in part and a while ago]
annd he's not doubt a bright guy ... but personally i
find s. weinberg more impressive and certainly more
articulate. "dreams of a final theory" is a more accessible
but still interesting book. it's also cheeper than the
GSW book ... which is a $50 "paperback" and fairly tough
going if you dont have say 2yrs of grad math. --psb
\_ did anyone in this thread express interest in
a "standard serious work?"
\- dear mr. too short: "phony physicists rarely write
standard serious works". --psb
\_ fuck off. -real physicist
\_ you lie. a real physicist wouldn't call herself
such (maybe "physics grad student" or "physics
prof"). i wont make judgments on whether she'd
be posting to the motd.
\_ doh! you got me! it turns out that i'm the
pompus ass sysadmin knowitall who learns
about the most useless theory in physics
to impress girls at parties, and you're actually
the physicist! my bad! |
| 2003/12/3 [Science/Biology, Science/Physics] UID:11286 Activity:nil |
12/2 FYI, after the APA Board of Trustees removed homosexuality as a
disorder from DSM-II in 1973, there was a big uproar from
psychiatrists. The issue was brought to a referendum, and out of
~ 10,000 votes, 58% voted that it should be removed from DSM-II.
http://www.worldandi.com/public/1997/april/ar5.cfm
\_ Wow. Science by vote.
\_ of course. it's fundamental principle which democracy
is build upon. We can not allow few elites hijack
the reality and the truth. Science should belong to the
oridinary people.
\_ In a qualitative science, could you do any better?
\_ Wtf is a qualitatiave science?
\_ One that relies on qualitative data. I.e. "He was
diagnosed as crazy" vs. "He is 73.2% crazy"
\_ Contrast with quantitative. It's fuzzy science, if it is
science at all.
\_ That was sort of my point. There are no fuzzy sciences.
There are analytic sciences (mathematics), and
empirical sciences (biology, physics, etc.).
\_ then, there is Chemistry. you can argue that it's
not a science at all. -- ex Chem Eng major |
| 2003/11/3 [Science/GlobalWarming, Science/Physics] UID:10912 Activity:moderate |
11/2 I want to share a story regards to shoulder-fire missile. In the late
1980s, I was talking to an immigrant from the mainland China.
What make him an interesting figure is that he used to work in
some rocket R&D/manufacturing facility in Gan-Su province. I
asked him rather China could make stuff as cool as shoulder-fire
missile like Stinger. He told me, to my suprise, yes. According
to him, China got a good R&D boost when then the Socialist
government of Afghanistan captured bunch American made
Stinger missles from the Muslim extremist rebel (read: TALIBAN)
which USA supported. It gave the mainland China half dozen of
those shoulder-fired missiles. By reverse engineering it, China
was able to make, though crude by comprison, a mock up that
actually works.
Isn't it kind of funny that both the regime which USA supported
and the Stinger missile technology it leaks out as result, are
coming back and haunt USA?
\_ Why would that be funny? You see, kid, there was this thingy a
few years back called 'The Cold War' in which two superpowers of
markedly different ideologies fought for global supremacy through
a variety of means. Control of obscure pieces of territory where
cash flow and stragetic positioning of intercontinental nuclear
weapons was the currency used in this 'Cold War'. Sadly, since
both of these Superpower thingies existed in the real world
(rather than your ESL anti-US utopia), nasty immoral things often
had to be done to keep the opposing ideological faction from
gaining the upperhand. This led to both of these regimes supporting
nasty evil religious or just plain nasty and evil dictatorships and
other things to keep the other in check. That there 'Cold War'
is now over, and sadly, these evil little regimes are still there.
It is a phenomenon often referred to by educated people as 'the
lesser of two evils'. Keep this one factoid in mind: You're not
nearly as clever, perceptive, or intelligent as you think you are.
\_ Yea really funny you fucking traitorous piece of shit. Go
back your homeland if its so great.
\_ technology is good for only 10 years, till which it'll be made
obsolete by other technology or be stolen and used against the
originator. It's happened to the Greeks, Egyptians, Chinese,
US vs. Brits, etc. Nothing new here.
\_ agree, then why we are so obsessed with 50 year old technology
such as Nuclear bomb and chemical weapon?
\_ Uhm, because they're weapons capable of inflicting casualties
in the 5-7 digit range relatively instantly? Because their
manufacture is pretty sophisticated? Maybe because the
materials are often difficult to obtain, create, or find?
Maybe because there are people out there that are willing to
inflict insane civilian casualties for completely ideological
reasons based strictly on hate?
\_ Hey, nice bit of intenional intellectual dishonesty and
stupidity. Is there a class where they teach that sort of
self induced blindness?
\_ this is not the first time in history. The Ballista technology
was taken away from the Roman army. The Greek fire was copied and
used against the inventor's home. The American colony got
the gunmaking technology from the Brits and won. The Japs got
the plane technology from Boeing to make lots of Mitsubishi Zeros
to attack Pearl harbor. The list goes on and on. I saw a documentary
that says a new war technology is good for only 10 years, after
which it'll be stolen or made obsolete.
\_ agree, that is why I thought it's silly to invade Iraq,
sanction North Korea over poliferation of nuclear bomb and
other WMD.
\_ The Taliban came later, but whatever. Anyway, as the above said,
this is standard in warfare. If you bring something to the
battlefield, the enemy will eventually get their hands on one and
reverse engineer it. If you don't bring a new weapon to the battle
then there was no point in making it, eh? In addition to the above
list, I'd like to add the bazooka which the WWII Germans eventually
captured. As the story goes, a few German generals got wiped out
by back blast during a demonstration, but hey, it's just a story.
\_ My point is not so much about proliferation of technology, as it
is bound to happen. I just thought that it's really silly to
proliferate technologies over muslim fundamental extremist.
-- OP |
| 2003/10/25-26 [Politics/Domestic/Crime, Science/Physics, Politics/Domestic/President/Bush] UID:10784 Activity:nil |
10/24 How much extra radiation do you get when flying during a Coronal Mass
Ejaculation? Like the one occuring right now.
\_ "When that bowel shock strikes the earth's magnetic field, it's
traveling a million miles an hour or more. So it's really moving.
That's a lot of particles, a lot of hydrogen particles protons and
electrons slamming in the magnetic field. And it sort of makes it
jiggle."
\_ You'll die.
\_ Sooner?
\_ Instantly. Like a marshmellow over a fire pit.
\_ Should you worry more about possible plane crash caused by
communication to control tower or GPS satellites being disrupted,
than the higher radiation that you body receives?
\_ In a word, Yes.
\_ Like a marshmellow. ZZZZT!
\_ ORBITAL LASERS!
\_ The Mafia with the help of the Men in Black and The
Evil Scientists for a Better Tomorrow would like to
attack to control The Orbital Mind Control Lasers.
Base attack is 11 or less. Anyone want to pay to
stop it?
\_ I have a B-1 Bomber with a 100 Megaton warhead.
\_ SDI!
\_ Since the Boy Sprouts have a controlling influence
on the Mafia, and since the Rand Corporation owns
the Men in Black, NPR will stop that attack on
their soveignity over the OMCL.
\_ Not yet they don't! I've got White Collar Crime!
Enron shuts off power to NPR's broadcast towers
and TOMC are mine! |
| 2003/10/24 [Computer/SW/Apps, Science/Physics, Computer/Theory] UID:10762 Activity:high |
10/24 IF AIM WAS AROUND WHEN QUANTUM THEORY STARTED
http://www.makeoutclub.com/03/page_messageboard.php?topic_id=323705
hahahahahahahahahahah! --maxmcc
\_ Dumbass.
\_ =(((((((((((((((
\_ ??????
PROFIT! |
| 2003/6/10-11 [Science/Physics] UID:28692 Activity:moderate |
6/10 Physics buffs: back in physics 7C, the prof said that some physics
genius/nobel laureate wrote a PhD dissertation that was only 3
pages, but I forgot who he was. Does anyone know about this?
\_ might have been laplace. -ali
\_ I think I remember Prof. Zettel saying something about
de Broglie's thesis on matter waves being really short. -emin
\_ bingo! That was it. I had Zettl too. (looking it up
it was actually 7 pages. oops.) Thanks.
\_ it's always better in the retelling. did you note he
used sub-pixel fonts and no margins? |
| 2003/2/13-14 [Science/Physics] UID:27401 Activity:very high |
2/13 What was the most impressive classroom science demonstration you've
ever seen? ok to inlude TV, but only if it *could* be done in a
classroom.
\_ O-ring in a glass of ice water.
\_ Detonation of a hydrogen-oxygen filled balloon.
\_ Thermit reaction. Very very bright and molten metal drips out
the bottom.
\_ first place nuclear fusion, followed by a photon torpedo
as a close second.
\_ Something called a "Roman Candle". Lighting up a bunch of different
chemicals that explode with different candles , starting with
18M sulphuric acid. When I was in HS, I did this experiment in front
of a bunch of 8th graders, who were thoroughly impressed.
\_ we put a flux capacitor in the teachers deloreon
\_ The one they do in Chem 1A during big game week with the blue
and gold solutions. ha ha ha.
\_ In HS, our crazy scientist physics teacher put the van de
graff generator up against the classroom's metal door knob.
so when the attendance boy came to open the door, he got
a nasty shock. our physics teacher giggled for hours. not
so much impressive as amusing.
\_ I always liked the demonstration of oxygen's magnetic properties
by dumping liquid oxygen between two poles of a magnet and watching
the liquid spin around as it evaporates. If you must have the
pyrotechnics, you could always light it and blow yourself up . . .
\_ Pure oxygen doesn't combust. It needs fuel.
\_ The smokey serpent one:
http://www.sas.org/E-Bulletin/2002-02-01/chem/body.html
\_ In what grade are you target students?
\_ second year undergrad, mostly EE students, some applied physics.
-op
\_ Dr Birkett's physics 7A demo when he shot a monkey (stuffed).
Which included a performance by cal band for some reason
\_ CAL BAND GREAT!
\_ Jacobson did it better. |
| 2002/12/11 [Science/GlobalWarming, Science/Physics] UID:26784 Activity:very high |
12/10 Physics question: When one lifts weights, s/he exerts more forces,
hence the pressure the ground s/he stands on receives more
pressure. Is that correct? My friend tried to tell me it is
rather because the object (the weights) are moving, it is the
acceration that translates into greater force hence greater
pressure. But shouldn't the object as a whole (the weights +
the weight lifter) be considered a still object since the area
touching the ground isn't moving? Any url reference to this
would be great.
\_ pressure is force per area, so if the are is fixed(the area
of the bottoms of your shoes if you are standing), then the
force is your weight plus the weight of the weights plus
the added force from the acceleration of the weights. this
added force is the mass of the weights plus your arms(measuresd
in slugs) times the acceleration you apply. if you don't bielive
\_ what do you mean measured in slugs? It doens't matter
what units you use. English units are confusing. Best
to use kg to measure mass, but slugs will work too.
\_ right. i was just making the point that slugs
are mass and pounds are force. IF you use kilograms,
you'd better use Newtons, which most people are
not familiar with.
that this aceleration adds force, accelerate the weights as
fast as you can, and feel the burn in the knees.
to keep the same force, but change preassure on the floor, just
change area: stand on tiptoes or sit down.
\_ You can also do the experiment by lifting dumbbell while standing
on a bathroom scale. The reading is roughly the same as the
force (although expressed in mass units) between your feet and
the ground when the scale is not there. Watch the reading
becomes higher after you grab the dumbbells and hold them steady.
Then watch the reading changing when you accelerate and
decelerate the dumbbells in the vertical direction.
\_ I understand f=ma. But ultimately, it's the weight lifter
that needs to exert more force. The acceration of the
weights is caused by the extra force the lifter has to put
out. My friend's argument is that the accerleration generates
more force, but isn't it really the oher way around in this
case? The fact of the weights moving at an accerlerated speed
and the greater pressure are both caused by the more force
exerted from the lifter, no?
\_ Don't confuse energy and force. I can slump on the sofa
like a big pig not spending a single calorie of energy,
but my fat butt would still be exerting a force on the
sofa. Remember Energy = Force x Distance Moved. I
am a lazy bum who don't like to move, and AnyForce x Zero
is still equal to Zero.
\_ hmm. I am more confused with weight v.s. force.
Isn't weight force in the first place? _/
Help me settle the bet here. My friend's arguement
is weight changes as objects are being lifted. But
my argument is it's the force that's changing, not
weight. Isn't weight simply the gravitational pull
on the mass? In this case, aren't both constant?
\_ What the bathroom scale usually measures is the
gravitational attraction (a force) between your mass
and the fat lump of mass we call the Earth. When you
hold onto two dumbbells like some dumb body builder
and stand on the bathroom scale, it is now measuring the
the gravitational attraction between "your mass
plus two dumbbells" and the Earth. When you are
further accelerating the two dumb bells upwards,
the bathroom scale is now measuring the above plus
an additional force exerted by the accelerating
dumbbells on your body. Remember "Action Reaction".
That's why when measuring yourself on a bathroom scale,
you try to be naked, so that there isn't any
extra mass, and you try not to jump up and down.
What your friend refers to as "weight" is what
is measured on the bathroom scale. What you
refer to as "weight" is the gravitational
attraction between your mass and the Earth's mass.
As seen above, the two of you are referring to
different things. The two are only one and the same
when you are naked and not jumping up and down.
I think I have been trolled. Oh well.
\_ Your friend's thinking is inherently flawed, but explain
it to him this way:
When you talk about a person's weight, you imply that
that person isn't moving. If he jumps up while on a
scale, his "weight" will increase as he jumps up.
This is cheating; you take weight when you're standing
still. So you can't be pushing dumbbells while taking
your weight.
Likewise, you can't raise your arms up and down. Ask
him if his weight is changing when he's pumping his
arms or jumping on the scale.
\_ conservation of angular momentum
\_ Huh?
\_ Check an elementary physics text. Or sit on a
computer chair, hold a spinning bicycle wheel and
twist it.
\_ Yeah I know what conservation of angular momentum is,
but what does that have to do with the questions in
this thread?
\_ the overall pressure's the same but your feet exert more.
\- if you have flies in a jar on a scale
the scale wil read the same whether they are
sitting on the bottom, the side or flying ...
but at lift off it will register more.
\- here is a fun problem: you have a uniform gold
chain of legnth l ... say 1meter ... with mass
m ... say 100 grams. you hold the chain l units
above a scale and drop it. so at t0 when you
release the chain, the scale reads 0 and at t1
then the chain is resting on the scale, it reads
m->100g ... plot f(t) between t0->t1 where f(t)
is what the scale reads. this might be sort of
unkind as an interview problem for a software
guy :-) --psb
\_ Birkett demonstrated and then explained
this in class once, but I forgot the
physical basis of it. Can you post it?
\_ typical physics h7a homework problem
\_ yeah, so typical.
\_ Ok, I give up. What is the solution?
I got a big complicated equation
( (7Mggtt)/(2l) ) which I don't think
is right. |
| 2002/6/26 [Science/Physics, Politics/Domestic/Immigration] UID:25199 Activity:very high |
6/25 http://www.baconanddear.com/imm-famous/2000-Noble-Prizes.php Almost half of the U.S. recipients of the 2000 Nobel Prizes were immigrants to the United States. In the fields of Physics, Chemistry and Physiology, three American immigrant scientists were rewarded for their outstanding achievements. According to a 1998 National Research Council Report, about a third of U.S. winners of the Nobel Prize were born outside of the U.S. Further, between 1901 and 1991, 44 of the 100 Nobel Prizes awarded to U.S. researchers were won by immigrants or their children. \_ a large fraction of these are a very specific group of people: european jews who immigrated by way of the nyc area. City College was a free school that did not have quotas on jews as did MIT, Harvard, etc in the 30's and 40's, and it produced an absurdly high number of nobel prizes for a free school no one had heard of. many factors combinded to make this incredible generation of scientists, but it was an oddity of history from which it is dangerous to draw general conclusions. \_ Don't bring facts into this. H1b == Nobel winner! Yeah! \_ They forgot to include relevant figures such as the percentage of the general US population that is 1st or 2nd generation immigrant. \_ Currently, 1st and 2nd generations make up about 20 percent, about 10 percent for each. \_ Aha, but what about in 1901? \_ How many H1-B's? \_ I hope this isn't some bizarre attempt to say that since the feds go out of their way to import top scientists from around the world that H1b's are good too. Just don't even go there, it's such a stupid comparison. We *should* be stripping the rest of the world of their top scientists. That's good for America. It is *not* good for American to import hundreds of thousands of the poorly trained dregs so Cisco and Sun can pay dirt to foreigners while more highly skilled US citizens are collecting unemployment. \_ have you considered that you're either demanding too much money, or not as highly skilled as you think you are? \_ Excuse me but I'm fully employed. You're trying to deflect the point (poorly). I'll spell it out for you again: Buying foreign Nobel quality scientists is good. Buying low wage low skilled workers to replace skilled Americans is not good. H1b's are not Nobel winners. Thanks for the cheap shot and the weak rhetorical attack. I suggest a few weeks in an intro Rhetoric course. \_ So you're not unemployed, just irrationally xenophobic? \_ You're still ducking. Thanks for playing, troll. \_ I wasn't the original poster. But, it is quite clear from your ignorant statements that you are quite xenophobic. The original poster said nothing about this article leading any proof to why H1-B visa status is good. He was just citing an example. However, your blanket statement about all H1-B's being untrained and and unfit for employment in the U.S. is indicative of poor mental hygiene. Go back to Georgia, you hick. \_ It was an obvious response to threads from yesterday. Not my fault if you weren't around. Go find it in the archives instead of slinging meaningless personal insults. It's really easy to scream "RACIST!" and dismiss someone entirely without responding. It shows "poor mental hygiene". It's always much harder to actually respond intelligently, especially when you're not. I'm done feeding you cookies, troll. |
| 2002/6/18 [Academia/Berkeley/CSUA/Motd, Science/Physics] UID:25134 Activity:high |
6/17 motd opinion poll:
CMOS will be replaced by some other technology for the
majority of personal computing applications
never
next 5 years
next 10 years ..
next 50 years
next 100 years
\_ Oh my god no! Don't take my CMOS! I think a poll on sibling incest
would have been more interesting. This is so nerdy.
\_ i have 50 inflation-adjusted dollars ridding on this
\_ i have 50 inflation-adjusted dollars ridding [sp inc] on this
a nerd.
in a bet with a co-worker. but then, i am indeed
a nerd. [motd spelling bitch was here]
\_ ok, jerkoff, you remember how to spell and i'll
remember how MOSFETs work and how to make them,
and we'll see which is a more usefull skill.
\_ it's not possible to know both device physics
and spelling? shrug. personally, i'm rooting
for soi, but i've seen simple cmos do some
amazing things i'd never have thought possible,
so no bet. heh. just flashed back to asking
dillon in the old fish bowl what that cmos thing
was about for my cs150 project.
\_ This narrows down who you are a lot.
Why not just sign your name? -PM
\_ why? there are a few of us around
who go that far back, and it's not
obvious who i am unless you actually
know us. if it helps, i think i have
the oldest file on soda.
\_ damn! defron has older files. fine,
oldest file amongst guys who still use
soda.
\_ nope, as it turns out donald does.
\_ Actually, root does (unless
you count files with timestamp
0 [a la 12/31/1969 16:00 PST].
See /csua/archive/lib/Fun/song.
\_ [deleted for lack of sense of humor]
\_ Yet another ESL drone who thinks he has unique
skills.... "They can't fire me! I'm valuable!"
Famous last words. |
| 2002/5/3-5 [Science/Physics] UID:24689 Activity:moderate |
5/2 hi. does anybody out there know about how physics postdocs do in
doctoral programs for finance, accounting, etc? any personal
stories, cautionary tales, etc, please write to me, hahnak.
thanks in advance
\_ hi.
\_ if you go from physics to finance with a phd from a name-brand
school, no post-doc is necessary, and you certainly don't
want to waste your time with some idiotic finance grad program.
for reasons that are perhaps a litle odd, there are lots of
finance type employers on wall street desperately trying to
recruit physics phds all the time. i am a second year grad student
in applied physics, and i periodically get solicited by these
people even though i am years from graduating. lot's of people
seem to go this route, but no one i know personally because
it tends to be the particle theorist wannabe loosers, and i'm
in condensed matter experiment. from what i've heard, expect
to make less than the *real* finance poeple, to work long
hours, to hate your boss, and to lead a pointless existence
in the most expensive city in the US(nyc).
in the most expensive city in the US(nyc). huh. this reply
was intended as a troll(although i honestly believe everything i
said.) apparently this is the wrong crowd.
\_ What part of physics studies is applicable in the financial
world?
\_ being able to think and create mathematical models.
\_ yeah, and also an understanding of the study
of random processes. |
| 2002/4/27-28 [Science/Physics] UID:24617 Activity:nil |
4/26 [stupid physics troll nuked AGAIN]
\_ die thread, die. |
| 2002/3/25-26 [Science/Physics] UID:24219 Activity:moderate |
3/24 PDI WINS ! FATALITY!
\_ Shrek was a highly inferior film. Dreamworks is a highly inferior
group. The Oscars are highly inferior as well, but I won't go into
any of these as my head aches too much already.
\_ Compared to Monsters Inc. and (gasp) Jimmy Neutron?
\_ Yes. Especially compared to Monsters, Inc.
\_ Indeed. Monster's Inc. was immensely superior.
\_ ??? Power and Data Interface??
\_ i think they mean PDI-Dreamworks
\_ Maybe next year, John. |
| 2002/2/12 [Academia/GradSchool, Science/Physics] UID:23839 Activity:very high |
2/11 What is the $ of a typical grad school and how much TA/RA money does
one expect to get relative to the tuition and the cost of living?
-still waiting for grad schools to reply
\_ in physics it's full tuition paid plus from 16 to 21 thousand a year
stipend.
\_ Because we need future weapon designers.
\_ yeah, i belive there are three reasons: we built the bomb
and there is not enough money in physics to justify
students taking large debt in school and we provicde
comparitivly cheap labor. fourty grand total a year including
tuition is still pretty cheap for what we do. and yes,
we design military technology of tomorow.
\_ a pacifist physics phd friend of mine thinks shes working
on detection equipment for nuclear treaty compliance of
some sort but it sounded like a better use was sticking it
on an interceptor so it can differentiate between real
and dummy/fake warheads.... I didn't break it to her. She
seemed so happy thinking she was using physics for peace.
\_ I dunno about other schools. If you've got a TA or RA full-time
position, you're going to get half/full ride on fees, +
about 18k to maintain yourself. This is in EECS/Berkeley.
Half ride for a TA, full for an RA, and half ride leaves about 2k
per semester in fees. --PeterM
\_ What's a "full-time TA/RA"? 20 hr/wk? 40 hr/wk? -alexf
\_ Nominally 20 hr/wk. However, some TA jobs are quite
a lot heavier. If you TA, pick your assignment carefully.
Half-time is 10hr/wk. --PeterM
\_ did you apply for any fellowships? those pay tuition+books+
somewhere around 20k a year, for about three years, on average...
-chialea
\_ no, I did not apply to any because both of my GPA and GRE
are lower than yours. I don't think that I'll qualify
\_ You never know what fellowship might apply.
There might be a fellowship targeted at anonymous
motd stalkers! --PeterM |
| 2001/9/16 [Science/GlobalWarming, Science/Physics] UID:22484 Activity:nil |
9/15 Anyone interested in a small nuclear reactor?
http://www.uic.com.au/nip60.htm |
| 2001/8/7 [Science/Physics, Finance/Investment] UID:22029 Activity:insanely high |
8/6 Are there any bioE majors on soda? My friend's advisor (Bryan Jones,
for those of you who are familiar) told her she had to take 8 tech
courses her sophomore year. I'm of the opinion that this is only going
to screw her and her gpa over. Thoughts?
\_ screw her?
\_ [ the joke got old months ago. deleted ]
\_ I have a degree in Biophysics and tried to take 7 tech courses my
junior year (including OChem and QM at the same time). Yes, it
screwed up my gpa and probably kept me out of med school. -ausman
\_ I took Physics 137A, Physics 105, Physics 112, Math 104, Math
110, Math 113, and Economics 101AB my junior year. I didn't do
so hot. Then again, the alternative is to stay in school forever
while you take the hard classes one at a time. If she doesn't
take the 8 classes then what are her options? --dim
\_ Yes, it's possible, and sometimes even the right thing to do. I've
had semesters when I've taken 4 techs, and without regrets. In most
cases, for most people, it's probably NOT the right thing to do,
given risk to GPA/academic standing, stress level, lack of free
time, etc. The best thing you can tell your friend is probably to
get a second opinion of some other faculty in the department, and/or
from other undergrads who have taken the particular techs she's
being pushed into, and then think for herself. -alexf
\_ Tech courses were fun while I was at Berkeley. Four at a time
is even better. If she fears them, maybe it's not for her.
For example, I feared four upper division CS courses. That was
not for me, but if she's got a knack --
\_ Math power pack: 104, 113, 110, 128A. Delicious, nutritious,
and educationally stimulating.
\_ in my experience, Bryan Jones is nearly always wrong. She should
plot out her academic future with help from sympathetic profs or
better yet upperclassmen friends. Best of luck and let us know
if she actually ends up needing to take 8 tech courses.
\_ At last something I really can help with. BioE is in the eng. science
cluster of majors. They are very much catch as catch can for advisors
and the advising I received was poor verging on criminal. I made
numerous mistakes in class choices, some of which I am still dealing
with as a result. By all means, get a second opinion. Unless your
friend is a whiz kid who is comfortable with the load, find a way
to balance out the 8 classes over time. It's better to just be in
school longer. Really. It is. Feel free to email me if you want to
talk about it more.
-- ulysses (BioE for first year, then grad. in Env Eng Sci, 1995)
\_ My brother is doing BioE and he seemed to be able to handle that
load just fine while keeping his GPA above 3.
When I was an undergrad I took 6 technicals 2nd year and 8 techs
junior year and it wasn't too bad. I even graduated above 3.
\_ I don't know what the case is outside of BioE and my own major, but
we needed a 3.5 or better to be seriously considered for graduate
school - and it is assumed you are going to grad school if you
are in an eng. sci. major. Also, don't forget that for BioE two
of those classes are the biochem sequence where you are head to
head with bloodthirsty pre-meds, many of whom are taking only that
one course or maybe one other. -- ulysses
\_ Are all ucb students this wimpy now, or is it just the bioE majors?
I was eecs, and I've never taken less than 15 units of technical
classes a semester.
\_ When I was a student, we walked uphill, both ways, in the rain.
\_ Pansy. We walked through blinding snow, and we didn't
have schools. We had treebark! We would sit down on
treebark and take notes on treebark, and we liked it! We
loved it. |
| 2001/6/14-15 [Science/Physics, Computer/Theory] UID:21510 Activity:kinda low |
6/13 Long lived quantum entanglement of 2 macroscopic objects has been
achieved:
http://xxx.lanl.gov/abs/quant-ph/0106057
Food for thought. -- ilyas
\_ Thaumaturgy scheduled for teaching at UCB in year 2011
\_ We will teleport your gonads into the icy environs of deep space!
\_ Eh. Note that this has only been submitted to Nature and thus hasn't
passed peer review yet. The results they claim do sound impressive,
but I'm holding off on the party for time being (and I'm not nearly
enough of a physicist to evaluate actual procedure used and the
consequent claims' validity). -alexf
\_ .5 milli seconds is longlived? not useful for engineers yet..
\_ for quantum computation, that is wuite long. If you could
get that kind of lifetime for a 10,000 qubit system,
you would have a real quantum computer.
\_ Even 200-300 qubits at that speed should kick the crap out
of the current state of classical machines. -alexf
\_ 0.5 ms is long for all scientist/engineers.
\_ that's not what their sexual partners think. |
| 2001/4/28-29 [Science/Physics] UID:21128 Activity:high |
4/27 Anyone here took phil 135 metaphysics? What the hell is metaphysics?
(at berkeley)
\_ Its the physics of the mind body and the soul.
Its the most important subject you can study for
the betterment of your life and all of humanity.
- Deepak Chopra
\_ Its the physics of the mind body and the soul. - Deepak Chopra
\_ Fake physics
\- if a bookstore has a sectional called "metaphysics" you know it
is a bad bookstore. if the "metaphysics" section is bigger than the
philosophy and physics sections put together, then it is a really
bad bookstore. For a long answer to your question (that is not too
hard to read) see I. Kant: Prologomena to Every Future Metaphysics
That May Be Presented as a Science. For an even longer answer,
Critique of Pure Reason ... "Hume took as his starting point a
single but important conception of metaphysics ... the connection
of cause and effect ... metaphysics consists, then, of a priori
knowlege ... to distinguish from pure mathematics, pure philos
knowledge ... i must refer the reader to the Critique of Pure
Reason, where the distinction between the two ways of using reason
are clearly and adequately presented." ok tnx. --Kant, Prologomena.
p.s. Kant is 277yrs and 1 week old today.
\_ I took it. Meta physics is a uber class of philosophy dealing
particularly with being, reality, mind, knowledge. It is
inclusive of sub branches of philosophy as epistimology,
ontology, theory of knowledge, philosophy of mind, etc.
Generally will asks questions such as: what is the nature
of being? What is truth? What does it mean to exist? What
is the relation of cause and effect? etc. Very interesting
topics but if you're not use to philosophy classes you might
be asking for too much. If you're not a philosophy major
don't be surprised if you get a C (or less) on your first paper.
\_ i used to be a philosophy major (among other things) i had
history of philosophy (heraclitus -> sartre); philosophy 132.
is this enough?
\_ history of philosophy is not philosophy proper, it's
history. So I don't know if it's enough for 135, but
definitely avoid courses in philo on Kant and Heidegger
unless you really really want to read a lot of difficult
writings.
\_ I'm making your burger. -philo major
\_ So how was that book on Kant? And I will have
a fries and a milkshake with that. Thanks.
\_ Do you know why the called him Kant? It was short
for Stupid Philospher, Can't Get a Job!
\_ Hey! I love Kant! -!psb
\_ I wonder if Nick "don't go into CS for the money"
Weaver is one of the morons commenting above. -tom
\_ camus can do, but sartre is smartre! |
| 2001/4/20 [Science/Physics] UID:21029 Activity:very high |
4/19 Say you have a long pole of some hard substance. If you push on
the end, how soon does the other end move? Is there some ripple
effect at the atomic level that propagates at some speed? If so,
is this "c"?
\_ Are you trying to figure out if you can transmit information faster
than the speed of light (say, a giant pole to another planet)? I
think mechanical energy transfers through a metal pole similarly
to how sound would through air.
\_ if you push on my pole, baby, i'll move faster than c
\_ Are you trying to figure out if you can transmit information
faster than the speed of light (say, a giant pole to another
planet)? I think mechanical energy transfers through a metal
pole similarly to how sound would through air.
\_ Yes, the sound speed in the metal. You're propagating
compression/tension waves, more or less. Not only
would it be < c, it would be WAY less than c.
\_ Since the bonds that hold the hard substance together are
electromagnetic, the maximum speed to transfer an impulse from one
end to the other would be the speed of propogation of an EM wave.
So, yes, c is the limit.
\_ Sure, c is "the limit", but your understanding is poor.
Consider hammering a metal train track with a sledghammer.
How long would it take to "notice" that the rail was hammered?
How long would it take your friend "joe" down the track
to hear that it had been hammered? The distance to joe
divided by the speed of sound in metal, that's how long.
Moving it is essentially the same as hammering it. It's
just a very large amplitude, slow frequency sound impulse.
What is the speed of sound in steel? Very high, but nothing
like c.
\_ hm, makes sense, thanks. so it seems the speed of sound in
diamond is around 10^4 m/sec. okay, there goes my plan
to revolutionize fiber optics. (fiber sonics?)
\_ What's the speed of light inside fiber optic cables then?
\_ approximately c/1.52. Index of refraction of glass
is 1.52 ( vacuum speed / material speed ) --jon
\_ Then how is using diamond going to beat fiber optics?
\_ damn. as I suspected, people are already working
on everything. i was basically thinking about
what they call wavelength division multiplexing.
those fuckers.
\_ I said "there goes my plan." Although, something
else occured to me. But this one might be the
million dollar idea. I'm sure you buy that huh?
Hmm. --original poster
\_ hey, don't feel bad. there are plenty
of very succesful internet companies that have
made all of their money via the reciprocal
motion of rigid rods. it just has to be the
right rod.
\_ The one they shoved up your ass as
they took all your money in exchange
for worthless options.
\_ Oops, never mind.
\_ damn. as I suspected, people are already
working n everything. i was basically
thinking about what they call wavelength
division multiplexing. those fuckers.
\_ take a look at negative ir.
\_ I think Einstein said nothing, not even information itself, can
travel faster than c. But I think some quantum mechanics guys
said otherwise. They said for certain pair of particles
far apart, if they do something to one particle, the other particle
responses in some way in a time shorter than light requires to
travel between the two. It's something like that, I don't know
exactly.
\_ Feynman explained this to me once, and I thought I understood
it at the time, but afterwards, I realized I had no idea what
he was talking about. Here it is:
http://www.stardrive.org/feynman.html -ausman
\_ You knew/met Feynman?!? Lucky dog.
\_ You are talking about "spooky action at a distance". The problem
with this analysis is that it forgets to take into account the
wave modes of the particles. There was a paper discussing this
last year in phy. letters or something.
\_ You can't use this to transmit a message, though. Imagine
that you and I have two coins that are mystically linked, so
that when they are flipped, they both come up the same way.
We both flip the coins a bunch of times, and -- wow! -- the
sequence of heads and tails that arises is the same for us
both. But we can't know this until we get together and compare
notes. Until then, it just looks like a bunch of random
coin flips. This quantum thing is like that.
\_ But you're assuming that "flipping a coin" is random.
It's not. If you train yourself, you can consistently flip
quarters to come up the same side pretty much every time. |
| 2000/5/5-7 [Science/Physics] UID:18182 Activity:high |
4/35 Does aluminum foil or white sheets of paper reflect more light, if the
direction of the reflected light is not important? -- yuen
\_ Are you talking about strictly visible light? IR? UV?
\_ I'm interested in daylight (5500K). -- yuen
\_Christ, get a clue. Get a strong light source and a dark wall.
Hold up a sheet of paper and a sheet of tin foil that are the
same size. Measure the size of the square of reflected light.
Estimate the intensity in a small area, and multiply by the
entire area of the reflected light. Very simple. Any fourth
grader could do it.
\_ WAG (wild-ass-guess): Metal over paper any day. However, to test,
put some paper and aluminum foil out in the sun for a few hours. See
which is warmer.
\_ This is incorrect advice. Just because something 'feels' warmer
does not mean it is. For instance, titanium watches feel
neutral on your hand, but steel watches feel cold (when you first
put them on). However, both are at the same (room) temperature.
The subjective sensation of coldness can often be caused by the
_rate_ of heat transfer, not the actual temperature. In the case
of watches, steel has a greater heat transfer rate, so it absorbs
more heat from the human skin in the same amount of time than
titanium. These rapid temperature changes is what the human
skin's thermal receptors are most sensitive to.
-- motd physics god
\_ i knew this, too. - motd physics weenie
\_ as tom pointed out on wall, this won't work for another
good reason: paper transmits light, aluminum doesn't.
so you need to check the temperature as well as the trasmitted
light. -ali
\_ take both into a dark room and flash a flashlight at them...
have it reflect against a wall. seems like a logical
test *shrug*
\_ this doesn't take into consideration the fact that aluminum
is specular and paper diffuse. the pattern on the wall will
look different. you need to add the TOTAL amount of energy
\_ Who cares?
reflected everywhere on the wall, not just look at the intensity
at one point on the wall. the only good quick way i can think
of this is to point a thin laser at the paper, measure the
reflected intensity at some angle, and scale to the rest of the
hemisphere, and do the same with aluminum, but measure the
reflected intensity near the surface normal. -ali
\_ The two sides of my foil differ. Which side you talking 'bout?
\_ If you want to grow pot, don't use aluminum foil. _Very_ hard to keep
flat enough to reflect light.
\_ I think of it this way - mirrors are made of melted metal (I don't
know which) poured over the back of glass. Mirrors are *very*
reflective. I believe that part of the reason is that the glass
holds the metal flat. Put paper on the back of glass, and you
don't get anything particularly reflective. If my life depended
on it, I'd choose aluminum. |
| 2000/1/8-10 [Science/Physics] UID:17195 Activity:nil |
1/8 Need 2 units? IB 98/198 DeCal course; Science in Science Fiction.
We watch movies, then have professors from the IB, MCB, Physics, Astro,
and CS departments tell us about the real science that inspired it.
Check out http://www.csua.berkeley.edu/~sofia/DeCal/decal.html for
more info. -sofia
\_ Deep. |
| 2000/1/1 [Science/Physics, Science/GlobalWarming] UID:17139 Activity:high |
12/31 Was the Y2K bug that big of a deal? Looks like its effects are
small and sporadic, so far. Would it have made that much of a
difference in terms of power/phones shutting off, etc, if people
didn't try to make everything compliant?
\_ It isn't over yet, fool. The U.S. hasn't rolled into Y2k yet! How
can you be so naive? The Rapture is coming!
\_ Wrong. Guam was one of the first to enter 2000.
\_ Guam is a tiny speck of nothing territory. It isn't a part
of the United _States_. We _own_ it. They also don't have
any nuclear power plants. So young, so foolish.
\_ "Better safe than sorry" -- more true today than at any time in
human history. |
| 1999/12/31-2000/1/1 [Science/Physics] UID:17135 Activity:moderate |
12/31 Any recommendation on a photography book for someone who happens to
have a solid background in physics?
\_ What does physics have to do with the art of photography? Or
are you looking for something that explains lenses and film?
\_ Not one that explains how films and lenses work but how to
apply them to achieve the expected effects with scientific
explanation.
\_ I doubt your vaunted physics background will help you.
\_ Are aeronautic Phds good test pilots? No. Get a fuckin life peterm |
| 1999/8/13 [Science/Physics] UID:16305 Activity:high |
8/12 Is it possible to take 37 units in one semester?
\_ With approval you are allowed to try anything. You won't pass
37 units unless it's mostly crap courses.
\_ Not sure if it's physically possible, but you have to get Dean's
approval to go past 20 or 21.
\_ It's possible if you need them for graduation; a friend of
mine did 38 his last semester. -calbear
\_ Are you sure he didn't attempt to slit his own throat?
\_ Pretty sure. He seems happy to me. He's currently
involved in a start-up for a couple of months before
leaving to New York to work as an attorney in mergers
and acquistions. -calbear
\_ Wait a second. Attorney? That explains everything.
His units were probably mostly in the humanities
and social sciences. I'd like to see someone take
38 units of science or engineering. --dim
\_ Everyone's different. I would die with that many
units of humanities, cuz I can't write worth shit
term papers.
\_ But clearly you could easily do 38 units
of science and engineering classes? Come on.
All you're admitting to is being a moron that
can't write. I submit that it would be
almost *impossible* for an undergrad to take 38
units of science and engineering courses
and pass with grades of C or better in each.
The reason? Problem sets and labs. Papers
are not near as time-consuming, ignoring
whether or not they are "easier". --dim
\- i think if you are one of these amazing
people [there were classes it took me 20hrs/week to
to the homework, while people i knew took 40 minutes,
but they also got 3 digit scores on the putnam ...
and didnt ever bring a pen or pencil or paper to
class to take notes] it can done. for a normal person
this would be impossible. i took 5 problem set classes
plus one political science class one semester and i
basically sleeped under 30hrs a week for the whole
semeser and only went home every few days [it was
also my highest gpa semester, but i was in a black
mood the whole time]. i think you couldnt physically
do the reading for 7 heavy reading classes, however
for many of those classes you can do quite well in
without doing much of the reading. --psb
\_ I guess I didn't have it as bad, but it was still
a pretty horrible experience for me. CS 164 with
Hilfinger, CS 184 with Sequin, EE 122, Polisci 2,
and project partners that were either lazy,
incompetent, or just ditched me half way through
a project. I didn't sleep much that semester but
boy did I learn a lesson about choosing classes.
--jeff
\_ I'm currently in my 5th year of EECS however
there was a semester in which I thought i should do
philosophy instead, so I took 4 philosophy courses
philos 12(foundations of logic), philos 25a(ancient),
philos 133 (language), philos 132 (mind)
and cs61c. This was all without approval from my
faculty advisor. Anyways to make a long story short,
I didn't do jack shit in any of the philosophy courses
and got 4 A's and a B. You can guess where the B came from.
I spent roughly 30 hours for the entire semester outside
of class for each philosophy course.
Compare that with two weeks of an upper div CS or EE class.
I now think that any dumbass can get a Berkeley degree,
but which kind of degree is what counts. I spend
15 hrs a week outside of class for each EE/CS course.
\-try taking h104, h113, 115, physics 137a+105.
one problem set due on wed, 2 on thr, 2 on fri.
you are too wiped out to do anything all weekend.
you learn a lot more about fear and trmbling that way
than reading kierkegaard.
\_ go go math power pack! -- ilyas
\_ Of course i don't mean to diss physics. as an
eecs major i respect math and physics
as more difficult, and realize it requires
much more thought. i couldn't do most upper div math.
and i know history is alot of work. im just saying
generally, that most non-science (anthro, poli sci,
bus, econ, etc.) don't know the meaning of blood
sweat and tears. i do think english and history
are siginificantly harder than other humanities
but getting through
math/physics/ee/cs/mcb/bio-e/meche/chem-e
means you are a bad mo-fo.
\_ Just to let you all know, the first two years of medical school
on most campuses is about 30 units or so, and it wasn't that bad.
A lot of work in amount, but not that hard conceptually. -drex |
| 1999/6/9-12 [Science/GlobalWarming, Science/Physics] UID:15931 Activity:kinda low |
6/9 Yet another Nobel prize for Berkeley:
http://enews.lbl.gov/Science-Articles/Archive/elements-116-118.html
\_ nobel prize, huh? possibly, but unlikely i think.
\_ wel gee, I could get a nobel prize too, if I had an
umpty-billion-dollar cyclotron, and free license to play around
as I see fit.
\_ D00D!!!1!!!! CYKLOTR0NS R 4 PUSS13Z!!!!1!!!1!!!!! ALL U N33D
2 G3T A N0B3L PR13Z 1Z A TRUSTY C=64 ---- 1F UR *DAMN G00D*!!1!
\_ I had a cyclotron once, but then the aliens came and took
it away just as I was about to discover The Truth.
\_ That's right -- and they gave it to *me*, because they
liked me better! Nyah!
\_ Go Bears |
| 1998/8/27 [Science/Physics] UID:14519 Activity:moderate |
8/26 Recommendations for a 1 unit (science unit only) EECS class I can
take so I'll graduate? --dbushong
\_ If you're a CS person, CS9?. If you're a science person, CS9X.
\_ I know two seniors taking 9C for a science unit.
\_ How about physics 111?
\_ EECS 39X, "Potstickers and the PDP-10: Brian Harvey, A Life"
\_ Comp Lit 39M, "The soda motd and its discontents" |
| 1998/8/25 [Science/Physics] UID:14502 Activity:high |
8/23 i have a friend coming from out of town next week. hes a
physicist and asked me to take him to what he calls a
'science bookstore'. ive never heard of such a thing, but
would like to go to one myself. he is interested in
buying physics books. is there a 'science bookstore' in
the bay area? im hoping to take him to a place other
than the asuc... [his work is in condensed matter theory,
if that helps] -hahnak
\_ Well, he would probably like the physics and related
sections of the campus bookstores. Also, Cody's is
fairly respectable though somewhat random the last
time I looked.
\_ best place i've been to is University Bookstore on University
Ave and High St in downtown Palo Alto. -ali
\_ ObStacy's for just sheer variety. --jon
\-Cody's has a pretty good selection of Springers. Occasionally
they have really good prices during their "Silver Sale" [silver =
physics, yellow = math]. ASUC actually has reasonable number of books
on condensed matter physics. [reasonable here is 3 instead of 0].
stacy's and [stanford] univeristy books are best bet for south bay.
[dont bother with kepler's ... it is an overrated bookstore ... they
are just good for fiction and "events"]. --psb
\_ There's also a Stacy's in SF (on Market, a block from the
Montgomery BART). Black Oaks is also worth checking out.
There are some real finds there. |
| 1998/4/13 [Science/GlobalWarming, Science/Physics] UID:13945 Activity:nil |
4/11 Sandia said a few days ago that they think they can get high-yield
nuclear fusion in a bit over a decade. Does anyone believe them or
have more information? If it's true, it would be a Good Thing.
\_ I'd love to read this. Give me a ref? I'll follow up
with my opinion on it... --PeterM
\_ http://www.sandia.gov/media/z.htm
\_ It is capital Z, yet htm extension. Weird. -muchandr
\-i was talking about commercial fusion power with a friend
of the family who works on fusion at LLL maybe 1.5 yrs ago, and he
said the press that implied it was "right around the corner, early
21st cent" were way off. "not in this decade". --psb
\_ Check out latest issue of Discover. There's a proposal of using
proton-boron reaction instead of conventional deuterium. -- cm1ee
\_ Saw the origional of that in Science a few months ago. Mostly
an "on paper" proposal. Nothing much more than that. |
| 11/22 |