Straight Dope August 01 2009

''I've seen pictures of Pangaea, the giant land mass that eventually separated into the continents we know today. But why were the continents smushed together like that in the first place? What made the land higher on that one side of the earth? Were there other continents we can no longer account for? Is it related to the asteroid that may or may not have smashed into Earth and helped form the moon?

— Chris D., Cranston, R.I.

Careful, bud. Thinking outside the box is great, but we don't want to cross the border into the completely insane. That's a chronic risk with continental drift, talk of which was a sure way to clear out your end of the bar at scientific conferences until the 1950s and which still inspires wacky theories. Asteroids don't figure in any of those I've heard about — but wait till you get a load of the expanding earth.

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