Geek Trivia: Holiest of holes

What is the largest impact crater in our solar system?

While there is still considerable debate about what, exactly, killed off the dinosaurs, one of the most compelling theories is that Mexico did it. Or, rather, that 65 million years ago, a 10-kilometer-wide meteor slammed into the landmass that would later become part of contemporary Mexico -- thereby throwing a huge chunk of that same proto-Mexican landmass into the atmosphere, wreaking untold environmental havoc across the entire planet and killing off the infamous thunder lizards in the process.

The primary geographic feature that this meteor left behind is the Chicxulub Crater. It's about 180 kilometers in diameter, it makes up much of the northern edge of Mexico's Yucatan Peninsula, and it stretches well into the Atlantic Ocean. It's also only the third-largest confirmed impact crater on the planet.

Second place goes to Canada, which is home to Ontario's Sudbury Basin. This too is the result of a 10-kilometer-wide meteor impact, though Canada's event took place much earlier -- 1.8 billion years ago.

This space rock, however, blasted out a crater 250 kilometers wide. But the intervening millennia have helped soften the edges of this formation, leaving the modern Sudbury Basin obviously discernible at only about 62 kilometers wide. The Canadian crater is also a bit more productive than Chicxulub, as the impact deposited significant amounts of precious metals in the local geology, making Sudbury one of the world's leading mining communities.

Still, even the metal-rich Sudbury Basin must take a back seat to the world's largest astrobleme (the technical term for a meteor impact crater): South Africa's 300-kilometer-wide Vredefort Crater. Again, a 10-kilometer-wide meteor slammed into mother Earth, in this case about 2 billion years ago, with a force sufficient to vaporize 70 cubic kilometers of rock.

The Vredefort collision was so powerful that the rock beneath the impact point actually rebounded, creating a raised dome at the center of the crater and generating a ripple of ringed crater-rims that radiate out from the center. Such features rarely survive in Earth's tectonically active geosphere; however, the Vredefort crater was significant enough that traces of its multi-ring crater are still detectable. There is no larger confirmed impact crater on the planet.

Still, as grand as Vredefort Crater is, it's a mere piker compared to the biggest, widest impact crater found in our local solar system -- one more than eight times as wide as Vredefort's most generous estimated diameter.


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By Jay Garmon

Jay Garmon has a vast and terrifying knowledge of all things obscure, obtuse, and irrelevant. One day, he hopes to write science fiction, but for now he'll settle for something stranger -- amusing and abusing IT pros. Read his full profile. You can a...