In terms of a family car vacation, the ancient asteroid that flew by Earth Friday may have seemed far away -- 17,200 miles.
In astronomical terms, however, Asteroid 2012 AD 14 was actually very close, much closer, for example, than the Moon's 239,000 miles. And computer projections of that asteroid's Earth-like orbit into the future currently forecast an upcoming earthly encounter of the explosive kind. More on that disastrous possibility in a minute.
This asteroid was spotted by Spanish astronomers about a year ago. It's one of an estimated 500,000 near-Earth objects, only one percent of which have been cataloged. It's about half the size of a football field in length and from a distance looks much like a pumice stone.
A meteorite (which is what asteroids are called after entering Earth's atmosphere) that severely rattled Russians Friday morning was merely coincidental to the flyby. Ever heard a major meteor explosion? Turn up your volume and watch this video: (More text below)
major meteor explosion? Turn up your volume and watch this video: (More text below)
And that Russian one was much smaller than the flyby, only an estimated 55 feet across and 10,000 tons of matter before starting its flaming plummet through the atmosphere, shattering and exploding to injure possibly as many as 1,000.
Asteroids hold interest for scientists because they are actual primordial debris, drifting galactic time capsules of minerals and matter created during the solar system's formation about 4.5 billion years ago. Those leftover clumps that didn't gravitate into forming planets have been flying about in the vacuum of space ever since, running into each other and cratering other planetary bodies like our Moon and Mars.