[Mr. K]

wow- interesting. How thick is the earths crust?

[rightofrush]

Think of the peel of an apple - The Earth's crust is proportionately thinner.

[rightofrush]

Think of the skin on an apple - The Earth's crust is proportionately thinner.

[LibWhacker]

Of varying thickness. In some places, often where there is a lot of volcanic activity, it's relatively thin. In other places, thicker. IIRC, the average is something like 50 miles.

In one astronomy course I took, they said almost none of the craters on the moon are associated with lava flows; i.e., the impacts did not punch right through the moon's crust and release a huge flood of lava. I don't even think the Chicxulub (CHEEK-shoe-lube) impact that wiped out the dinosaurs is associated with any release of lava. And that asteroid was about six miles across.

So realistically, it would take an enormously huge impact on earth to do that, even if it happened to hit on the boundary of a continental plate. And if the impact were THAT huge, we'd have a lot more to worry about than just lava. IMHO, it's kind of strange that they would even mentioned the possiblity of a half-mile asteroid puncturing through the earth's crust.

[Graewoulf]

The Earth's Mantle is somewhere between 2886 and 2993 kilometers thick. The Mantle's Crust (=Earth's Crust) varies between 6 and 60 kilometers, with the thinnest being near Mid-Ocean Rifts, and the thickest being under continents.