9. Its friends are still out there
From Chelyabinsk and other recorded airbusts, Campbell-Brown and her colleagues estimate that the number of objects with diameters of 10 metres or more that could hit Earth is 10 times as large as previously assumed. Many of them, like Chelyabinsk, are invisible. "Without massive space-based surveys, these will get by us fairly often," she says.
10. It could have been worse
The meteor came in at an oblique angle, which spread its energy over a large area. Scientists often compare the damage an incoming asteroid might do to that of a nuclear weapons test of equivalent energy, but Chelyabinsk proves that this model doesn't work in all cases. "For any one point on the ground, the damage was less than you might expect for a nuclear weapon," she says. On the other hand, most of the damage Chelyabinsk caused came from its shock wave. If it had come straight down at Earth, the shock wave would have been distributed horizontally in the atmosphere, vastly reducing its reach. "It's kind of a trade-off," Campbell-Brown says.
Correction: Since this article was first published on 6 November 2013 we have clarified the percentage of the parent body that the fragments in header number 3 add up to
If you would like to reuse any content from New Scientist, either in print or online, please contact the syndication department first for permission. New Scientist does not own rights to photos, but there are a variety of licensing options available for use of articles and graphics we own the copyright to.