Killer Asteroids Are Good For Life 70
Hugh Pickens writes "NASA reports that according to a study by Rebecca Martin and Mario Livio asteroid collisions may have provided a boost to the birth and evolution of complex life on earth delivering water and organic compounds to the early Earth and accelerating the rate of biological evolution with occasional impacts to disrupt a planet's environment to the point where species must try new adaptation strategies. 'Too many asteroids, and you've got an unrelenting cosmic shooting gallery, raining fiery death from above,' writes Fraser Cain. 'Too few asteroids, and complex life might not get the raw material it needs to get rolling. Life never gets that opportunity to really shake things up and evolve into more complex forms.' Martin and Livio suggest that the location of an asteroid belt relative to a Jupiter-like planet is not an accident. The asteroid belt in our solar system, located between Mars and Jupiter, is a region of millions of space rocks that sits near the 'snow line,' which marks the border of a cold region where volatile material such as water ice are far enough from the sun to remain intact. 'To have such ideal conditions you need a giant planet like Jupiter that is just outside the asteroid belt [and] that migrated a little bit, but not through the belt,' Livio explains. 'If a large planet like Jupiter migrates through the belt, it would scatter the material. If, on the other hand, a large planet did not migrate at all, that, too, is not good because the asteroid belt would be too massive. There would be so much bombardment from asteroids that life may never evolve.'"
Good for life (Score:5, Insightful)
But not as we know it, Jim
We don't need any more of those. (Score:4, Insightful)
It was perhaps great for life back in the old days a couple billion years ago. But it wouldn't be very good for us today. Can we not have any more mass extinction events, please?
Anyway, we're doing a pretty fair job of causing our own mass extinction. Nuclear war, tailored viruses, nano-machines run amock, artificial intelligence that wants us gone. Yup, lots of chances to do ourselves in and give the Earth a chance to start over.
100 percent of the time, everytime (Score:4, Insightful)
Basically, intelligent life can only evolve under circumstances identical to the way we evolved.
"100 percent of the cases where we know life evolved, these circumstances prevailed. Therefore..."
Re:We don't need any more of those. (Score:4, Insightful)
Killer asteroids are like political change. (Score:4, Insightful)
Killer asteroids are good to life that might emerge after the collision. But if you poll the existing life on the planet? meh! Its popularity is going to be very very bad.
Re:Nice, but speculation (Score:4, Insightful)
But it is potentially useful speculation.
No, it's not terribly useful.
Instead of trying to find life on everything floating around random bits of fusion, look for specific parameters.
We can speculate that it takes a certain type of asteroid belt for a planet to have complex life, but since we don't have real evidence to prove that, it would be premature to filter our planet search based on a parameter of which we don't know the relevance. Especially since the only way to figure out whether it's relevant would be to look hard at all planets, in order to confirm or disprove the hypothesis.
Relying on a hypothesis that turned out not to be valid has already slowed down exoplanet searches once. Hot super-Jupiters could have been found by transit searches long ago, but nobody thought to devote resources to do the observation, since "of course" Jupiter-sized planets could only exist at high distances from their stars.