If there are other planets like Earth out there, at least one in three probably harbors life, according to Charles Lineweaver and Tamara Davis of the University of New South Wales in Sydney, Australia. If life can arise on planets unlike ours, then the odds on finding life are even more favorable.
We can get important knowledge from the fact that life on Earth seems to have evolved very quickly, say the researchers. According to the earliest fossil records, life took no more than about half a billion years to gain a foothold, once the planetary conditions were amenable. This time scale might actually have been much less – even instantaneous in geological terms.