An asteroid will pass very close to Earth on February 15, 2013. Astronomers have estimated 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 satellites (about 26,000 miles up). No, 2012 DA14 won’t strike us in 2013. There was a remote possibility it might strike us in 2020, but that possibility has been ruled out also.
What will happen when it passes us? … Not a thing. The day it passes, most of us won’t see it or be aware of its passage, in any way. The asteroid won’t alter the tides. It won’t cause volcanoes. It’ll just sweep closely past us, as millions of asteroids have done throughout Earth’s four-and-a-half-billion-year history. The asteroid will be within range for small telescopes and solidly mounted binoculars, used by experienced observers who have access to appropriate stars charts. Here’s what NASA says about its visibility:
“On [February 15, 2013], the asteroid will travel rapidly from the southern evening sky into the northern morning sky with its closest Earth approach occurring about 19:26 UTC when it will achieve a magnitude of less than seven, which is somewhat fainter than naked eye visibility. 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 an object that was about 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. Pretty much would just flatten a city.
UPDATE: check out the shocking footage captured of the massive space rock entering earth's upper atmosphere.