How to Survive a Killer Asteroid – WIRED

When Galileo trained his telescope on the moon in 1609 and discovered perfectly circular craters dominating its topography, astronomers began to wonder how they formed. A few astronomers, like Franz von Gruithuisen, an early-19th-century German, proposed asteroid impacts as the cause. But most rejected this theory based upon one simple, supremely confounding fact: The moons craters are almost perfect circles. And, as anyone who has thrown a rock into dirt can tell you, that isnt what an impact scar…

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