Two weeks ago, NASA's Opportunity Rover discovered the largest meteorite yet observed on Mars. Sure, any space debris can be an exciting discovery, but the rock's size has its own cool implications: Mars's atmosphere used to be a lot thicker.
Martian Ice Ages Bolster Case for Life on Red Planet
Just ten million years ago (a geological eyeblink), Mars could've had an ice age. Even cooler, it may have been one of several, meaning the planet underwent freeze/thaw periods much like those here on Earth. And that means — you guessed it — the chances for liquid water and life on the Red Planet just went way up.…
