I hate to beg the obvious, but why must live arise terrestrially?
As I recall, many species on Earth produce their food through consumption of raw chemicals. White and black deep sea smokers have large amounts of organisms that consume chemicals normally deadly to survive. Why couldn't this happen in space in some form? Life could have arisen only a few billion years after _____. Others have mentioned that amino acids have been found in space. This would seem to indicate that the foundation for life is not necessarily terrestrial.