On February 15, 2013, 2012 DA14 passed within the moon’s distance from Earth – closer than the orbits of geosynchronous satellites.
A near-Earth asteroid – called 2012 DA14 by astronomers – swept safely past Earth today (February 15, 2013). At its closest to us, it was within the orbit of the moon (which averages about a quarter million miles away), and closer than some high-orbiting communications satellites – about 17,200 miles (27,680 kilometers) away. The asteroid sped harmlessly past, with its closest approach today at 1925 UTC (1:25 p.m. CST). Many online viewing sessions are still scheduled for later today, as darkness falls in various parts of the world. This movie from the Samford Valley Observatory in Brisbane, Australia, shows the progress of asteroid 2012 DA14 across the night sky as it neared its closest approach today. Astronomers captured this video approximately six-and-a-half hours prior to the asteroid’s closest approach. The movie has been sped up 50 times.
Meanwhile, only hours before the asteroid’s closest approach to Earth, a meteorite struck in Russia, injuring nearly 1,000 people, according to media reports. Although asteroids are known to sometimes have their own moons, or travel in swarms, NASA now says the meteorite is not associated with asteroid 2012 DA14.
This image of asteroid 2012 DA14 (the white dot in the middle of picture) was taken by the FRAM Telescope in Argentina, part of the GLObal Robotic-telescopes Intelligent Array (GLORIA) project, in advance of its close – but safe – approach to Earth. It was obtained at 0:53 UTC on Feb. 15, 2013 (7:53 p.m. EST, or 4:53 p.m. PST, on Feb. 14). Image credit: GLORIA project/FRAM/NASA
Asteroid 2012 DA14 paased closest on February 15, 2013. As the image above shows, it passed much closer than the orbit of the moon - closer even that orbiting geosynchronous satellites (22,000 miles). View larger. Image Credit: NASA
What happened when Asteroid 2012 DA14 passed closely in 2013? Most of us could not see the large asteroid 2012 DA14. This asteroid is not large enough to alter the tides. It can’t cause volcanoes. It has 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. Asteroid 2012 DA14 will be within range for small telescopes and solidly mounted binoculars, used by experienced observers who have access to appropriate stars charts. Indonesia was favored for viewing, because it was the middle of the night there when the asteroid was closest. Europe and the Middle East were also in a location to view the asteroid, potentially. But this is a challenging observation. Even those familiar with using binoculars and telescopes will need some experience to track the object as it moves rapidly across the skyClosest Earth approach occurred about 19:26 UTC when the asteroid achieved a magnitude of less than seven, which is somewhat fainter than naked eye visibility. About 4 minutes after its Earth close approach, the asteroid was expected to pass into the Earth’s shadow for about 18 minutes or so before reappearing from the eclipse. You can be sure experienced astronomers will be watching for that event, and hopefully some will capture video. What do we know about asteroid 2012 DA14? Asteroid 2012 DA14 is a little guy, compared to some asteroids. It is thought to be about 45 meters across (nearly 150 feet across), or about the length of half an American football field. Its estimated mass is 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 2.4 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. But no crater was ever found. Scientists now believe a small comet struck Earth. That event has been estimated at 3 to 20 megatons. So 2012 DA14 is in the same approximate realm as the Tunguska comet (which, actually, might have been an asteroid instead). It would not destroy Earth, but it could flatten a city. Of course, about 70% of our world is covered by oceans. That means the most likely landing spot of any incoming asteroid is in the water – not on a city or other populated area. Astronomers at the Observatorio Astronómico de La Sagra in Spain discovered 2012 DA14 in early 2012. We know 2012 DA14′s orbit is similar to that of Earth. That is one reason the asteroid eluded astronomers until recently. Astronomers will be tracking 2012 DA14 in the future. Will 2012 DA14 strike Earth in 2020? No. 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. It turned out they didn’t have to wait until 2013. By May, 2012, astronomers had ruled out even the remote possibility of a 2020 collision. Astronomers say that 95% of asteroids large enough to do damage on Earth are now known. Still, 2012 DA14 and asteroids like it are sobering. Bottom line: The near Earth asteroid 2012 DA14 had a very close pass near Earth on February 15, 2013. It swept approximately 21,000 miles from us – much closer than the moon’s orbit and closer than geosynchronous satellites. Meanwhile, a meteorite struck in Russia early in the day on Friday on February 15. Although asteroids do sometimes have moons, or travel in swarms, NASA says the meteorite is not associated with asteroid 2012 DA14.
source and credit a earthsky
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