Besides ending life on planets through impacts, asteroidsmay also spread life throughout the universe. Although thislife is in the form of tiny bacteria which are only thebeginning of a long evolution to intelligent life, it doesmean that most life will be carbon-based, so if we ever domeet aliens we may recognize them. The planet(s) where lifeoriginated may have died long ago, but thanks to spacerocks, life still exists.
Maggie McKee writes in New Scientist that the nearby starsystem Tau Ceti, which astronomers think could have life onit, has 10 times more asteroids and comets than are in ourSolar System. They could have seeded life on these planetsbut they probably killed it off as well.
Astronomer Jane Greaves says, "It is likely that they willexperience constant bombardment from asteroids of the kindbelieved to have wiped out the dinosaurs?It is likely thatwith so many large impacts life would not have theopportunity to evolve."
"You could argue the other way as well," says astronomerGlenn Schneider. Life could exist if the impacts don?t occurin the habitable zone?the region around its Sun whereplanets having liquid water can exist. This is the areawhere it's not so hot that water evaporates or so cold thatit freezes. The existence of a huge, Jupiter-like planet inone of the outer orbits could also make a difference, sinceit would absorb many of the incoming asteroid impacts.
Astronomers are beginning to think there's life on Earthbecause asteroids are relatively rare here. Astronomer MarkWyatt says, "It could be that the Sun passed relativelyclose to another star at some point in its history and thatthe close encounter stripped most of the comets andasteroids from around the Sun."
One thing all higher life forms need to learn to do is totrustour vibes. It's a better way to live. You can listen toAnne Strieber's interview of Sonia Choquette starting July 24!
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