New astronomical data suggest that life on Earth may have been carried to foreign planets as a result of ancient asteroid strikes. “The idea is if a planet has life, like Earth, and if you hit it with an asteroid, it will create debris, some of which will escape into space,” said astronomer Mauri Valtonen of the University of Turku in Finland. Astronomers theorize that life would have been most easily carried to other planets some 4 billion years ago when our sun existed among thousands of nearby baby stars and their planets, which were just beginning to form.
What’s the Big Idea?
To search for foreign star systems where Earth’s brand of life might currently exist, Valtonen is now looking for stars that may have been born in the same nursery as our sun. So far, he has found two stars, which given their current trajectory and distance from the sun, may be its cousins. Were an asteroid strike to have thrown some Earthly amino acids into space, they could have been shielded in a piece of debris just one meter across for millions of years, until that debris landed someplace. “If it happens to land on a planet with suitable conditions,” said Valtonen, “life can start there.”
As our ability to identify planets beyond our solar system improves, it is becoming clear that our planetary neighborhood may not be so unique, meaning other Earths are well within the realm of possibility.