David Ewalt reports on asteroid 99942 Apophis, a hunk of space rock discovered back in 2004 that astronomers said had “a small chance” of collision “with the Earth in the year 2029, causing an explosion equivalent to 1480 megatons of TNT–nearly 30 times larger than the biggest hydrogen bomb ever detonated.”

We had a “close pass” with the asteroid yesterday—veering around 9 million miles close to our planet.

According to Ewalt, scientists are now claiming the asteroid is about 20% bigger than they first thought, and even though it’s still not likely that Apophis will collide with our planet, if it did the impact would be even more dire. The near pass should help scientists project collision likelihood well into the future.

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