The idea of panspermia is that life originated on another planet, which was then impacted to eject material into space, which then migrated to planet Earth, seeding our world with the earliest life forms. Panspermia can be extended to the idea that Earth-based life has subsequently been spread elsewhere through the same type of process. (Tobias Roetsch/Future Publishing via Getty Images)

Was Life On Earth Brought Here From An Alien System?

And could Earth-based life provide the seeds for biology elsewhere?

Today, on Earth, there’s an enormous variety and diversity of life on our planet. Every single surviving lifeform appears, in some fundamental way, to be related to every other lifeform; life appears to have a universal common ancestor. As we go farther and farther back in time — from the fossil record, for example — we can see that life was:

• less complex,
• less differentiated,
• had smaller numbers of unique sequences in its genetic code,
• and, if we go back before a certain critical point, lacked many of the developments that we now perceive as critical in leading to human beings.

Before a certain point, mammals didn’t exist. Before that, life only existed in the water, not on land. Prior to that, sex hadn’t evolved; prior to that, all organisms were merely single-celled. And yet, as far back as we can trace it on Earth, we have never yet come to an epoch where we can say with any degree of certainty that life did not exist. It raises a tremendous possibility: that the life that began on Earth originated elsewhere in the Universe, before even the formation of Earth. Not only is that possible, but it’s possible that…