mars rocks or earth rocks

[razman]

Rocks have been found on earth from Mars.so one must assume that rocks from Earth have found their way to Mars. So could Bacteria have travelled with these rocks, survived, only to be discovered by future explorers on the red planet and declared as Martian life and really it would be ancient Earth life?

[jake-the-peg]

It's possible but I'd say highly unlikely.

Most of such rocks are likely to have been put in orbit during the Hadean or heavy bombardment period and there's no chance that life could have formed then.

It would also have to have survived for thousands if not millions of years in space and although some extremophiles have survived space it's a very harsh environment with a lot of UV and that period of time it's pretty unlikely.

Add those two together and I'd think winning the lottery was more probable

[weecalf]

Are there earth pubs on mars cause theres....

[HowardKennitby]

How does anyone know where a rock is from?

[jake-the-peg]

I think (and Geology is not my strong point) that you will have trapped gasses in the rock of the Martian atmosphere.

More about identifying a general type of meteorite here:


http://www.aerolite.org/found-a-meteorite.htm

[jomifl]

All life on Earth shares a common ancestry as is indicated at a molecular level. The spur to finding extra-terrestrial life is the possibility of finding a form of life that operates with a completely different chemistry.

[Old_Geezer]

They read the label the museum puts on it.