Apparently, we're all Martians...

[Khas 12,158]

http://www.space.com/22577-earth-life-from-mars-theory.html

[Tyralak 12,068]

With some people I know, it doesn't surprise me. It seems I've heard this theory before. It's not really a new idea. However, if life had originated on Mars, I find it odd that the rovers haven't found any trace of organisms. Living or dead.

[Khas 12,158]

Well, fossilization is a rare process.  For all the info we have on life on Earth millions of years ago, our own fossil record is sketchy at best, since so many bodies never fossilize, even if they had hard parts such as bones or shells, to say nothing of microbes.

 

However, cell-like structures HAVE been found in Martian meteorites that landed here on Earth.

[Afishymeadow 534]

Hopefully, remnants of past life will be discovered on Mars. Or maybe, hopefully extant life is there ... somewhere?

[Jason 27]

I am my reason to think unlikley since life on Earth start something like 4 billion years ago.

[Khas 12,158]

The theory was that life started on Mars over 4 billion years ago, hitched a ride on a rock that was blasted from Mars by a volcanic eruption or asteroid impact, ended up crashing here on Earth, and blossomed on Earth while Mars went dormant.