A handful of rocks [from Earth] could even have made it to planets around other stars. Once such could be Gliese 581, a red dwarf 20 light years away with a super-Earth orbiting at the outer edge of its habitable zone, where water could be liquid. Hana and colleagues calculated that about 1000 rocks from the Chicxulub impact could have reached that far in about a million years, meaning any life that made it would have had 64 million years to develop - or die off.-- from How Earthly life could populate space by panspermia.
14 April 2012
Speculative, but fun: