www.csua.org/u/z5p -> earthsky.org/space/asteroid-2012-da14-will-pass-very-close-to-earth-in-2013
Asteroid 2012 DA14 to sweep close on February 15, 2013 Asteroid 2012 DA14 on February 15, 2012 Asteroid 2012 DA14 on February 15, 2012 It'll pass within the moon's distance from Earth - closer than the orbits of geosynchronous satellites.
Email A near-Earth asteroid - called 2012 DA14 by astronomers - will pass very close to Earth on February 15, 2013. Astronomers estimate that, when it's closest to us, it'll be within the orbit of the moon (which is about 240,000 miles away), and within the orbits of geosynchronous satellites (about 26,000 miles up). Astronomers' calculations of asteroid orbits can be trusted.
Asteroid 2012 DA14 will pass closest on February 15, 2013. As the image above shows, it will pass much closer than the orbit of the moon - closer even that orbiting geosynchronous satellites (22,000 miles).
Image Credit: NASA What will happen when Asteroid 2012 DA14 passes closely in 2013? On the day it passes, most of us won't see it or be aware of its passage, in any way. It'll just sweep closely past us - as millions of asteroids have done throughout Earth's four-and-a-half-billion-year history - some in your own lifetime. The asteroid will be within range for small telescopes and solidly mounted binoculars, used by experienced observers who have access to appropriate stars charts.
About 4 minutes after its Earth close approach, there is a good chance it will pass into the Earth's shadow for about 18 minutes or so before reappearing from the eclipse. When traveling rapidly into the northern morning sky, 2012 DA14 will quickly fade in brightness. Asteroid 2012 DA14 is a little guy, compared to some asteroids, although its size has not been pinned down precisely. It is thought to be about 45 meters across (nearly 150 feet across), with an estimated mass of about 130,000 metric tons. If a space object 150 feet wide were to strike our planet, it wouldn't be Earth-destroying. But it has been estimated that it would produce the equivalent of 24 megatons of TNT. How does that compare with other known impact events on Earth? In 1908, in a remote part of Russia, an explosion killed reindeer and flattened trees.
as the Tunguska comet (which, actually, might have been an asteroid instead). It would not destroy Earth, but it could flatten a city. That means the most likely landing spot of any incoming asteroid is in the water - not on a city or other populated area.
Observatorio Astronmico de La Sagra in Spain discovered 2012 DA14 in early 2012. That is one reason the asteroid eluded astronomers until recently. You can be sure that many astronomers are carefully tracking 2012 DA14 now. In other words, it's tilted sightly with respect to Earth's orbit around the sun, and, like Earth's orbit, it's not circular but elliptical - like a circle that someone sat down on.
According to Bad Astronomer Phil Plait, who appears to have used a computer program to look at its orbit: The asteroid spends most of its time well away from our planet. However, the path of the rock does bring it somewhat close to the Earth twice per orbit, or about every six months.
That's usually about the scale of these encounters -- it misses us by quite a margin. If we know it will miss us in 2013 and in 2020, why are astronomers still watching? In fact, the orbit of 2012 DA14 is not entirely pinned down, although it is known well enough to say for sure: it will not hit us next year, or in 2020. It should be close enough to catch the attention of virtually everyone on Earth in February 2013, on what's sure to be a media field day. In March 2012, when a collision between 2012 DA14 and Earth in 2020 was still remotely possible, I asked astronomer Donald Yeomans to clarify the risk. Yeomans is, among other things, manager of NASA's Near-Earth Object Program Office at NASA's Jet Propulsion Laboratory. In March 2012, he told EarthSky that a 2020 collision between Earth and asteroid 2012 DA14 was ... approximately one chance in 83,000, with additional remote possibilities beyond 2020. However, by far the most likely scenario is that additional observations, especially in 2013, will allow a dramatic reduction in the orbit uncertainties and the complete elimination of the 2020 impact possibility. By May, 2012, astronomers had ruled out even the remote possibility of a 2020 collision. Bottom line: The near Earth asteroid 2012 DA14 will have a very close pass near Earth on February 15, 2013. It will sweep approximately 21,000 miles from us - much closer than the moon's orbit and closer than geosynchronous satellites. Its orbit around the sun can bring it no closer to the Earth's surface on February 15, 2013 than 32 Earth radii.
Deborah Byrd Deborah Byrd is Founder and President of EarthSky, which she created in 1991. EarthSky is a digital media company that brings science and nature to millions of people around the world. Byrd has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. Besides blogging, Byrd is Editor-in-Chief of all EarthSky websites and social media outlets, and she oversees EarthSky's science podcast series - now in 90-second, 60-second and 22-minute audio formats, and in video - in English and Spanish - with about a dozen new EarthSky audio and video podcasts released every Monday. A science communicator and educator for 35 years, Byrd believes in science as a force for good in the world and as a vital tool for the 21st century. Astrophysics, the night sky and imagining space travel remain among her most enduring lifelong passions.
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