Mars is a good deal smaller than Earth. It lost its atmosphere and water. Mars at one time had rivers and lakes, perhaps even seas. Water, particularly, is the essential to life as far as our understanding goes.

Earth is not going to end up like Mars, any more than you are going to end up like me (a foolish old man with no teeth).

Manilius says it so well: "...and our end is consequent on our beginning."

The Mars rover "Opportunity" was set down on Mars' surface in 2004 I believe in a pinpoint landing: she reached the surface of Mars softly, just 19 miles from her intended landing spot if memory serves me. That ain't bad shooting on the part of the scientists who pulled the trigger -- a moving target millions of miles away. She was designed to complete a three month mission, and here she is still traveling and working, 7 years later.

Ha. A friend of mine, Ed, had to take his DOT physical this month. Ed is 62. They practically gave him the 3rd degree (they asked him the same questions -- several of them -- 4 times) because they could not believe a man his age had no ailments, took no medicines. I'm 69, same story. Old Ed and me, we take a lickin' and keep on tickin', just like Opportunity.