Regardless of how plausible you find the theory of Darwinian evolution to be, there's still no secular explanation for how life got started in the first place. (For starters, read about the problems posed by earth's oxidizing atmosphere.) So some secular scientists have decided to punt and consider the possibility that life came to earth on a meteor.
This once-controversial notion holds that the universe is filled with the ingredients of microbial life, and that earthly life first came from the skies as comet dust or meteorites salted with hardy bacteria.
"Studies have shown that microbes can survive the shock levels of being launched into space," said Charles Cockell, a microbiologist at the Open University. "And as more and more organisms are discovered under extreme conditions, it's become more plausible that things could survive in space for the time it takes to go from one planet to another."
Not long ago, Cockell's claims would have been greeted with scientific derision. But as scientists learn more about Earth and space, the theory, which goes by the grandiose name of "galactic panspermia," seems less far-fetched.
Less far-fetched than the idea that God created earth and the life that's on it? Maybe... if your starting point for every hypothesis is that there is no God.
In April, Columbia University chemist Ronald Breslow traced the molecular signatures of earthly amino acids to those of neutron stars.
"Everything that is going on on Earth occurred because the meteorites happened to land here. But they are obviously landing in other places," he said at the time. "If there is another planet that has the water and all of the things that are needed for life, you should be able to get the same process rolling."
Completely unfalsifiable, so it could be true! If you want to put your faith in interplanetary microbes, I guess that's up to you.