You Need Just the Right Amount of Killer Asteroids to Promote Complex Life

By | November 5, 2012

You Need Just the Right Amount of Killer Asteroids to Promote Complex Life

… Sure, asteroids can be planetary annihilators, scouring the surface of a world with fire and molten rock. But asteroids might also help seed a planet with the right ingredients to set up the conditions for life, and give that life encouragement to evolve more complex survival strategies.

As with all things, it’s just about balance. Too many asteroids, and you’ve got an unrelenting cosmic shooting gallery, raining fiery death from above. 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.

This conclusion comes from Rebecca Martin, a NASA Sagan Fellow from the University of Colorado in Boulder and Mario Livio of the Space Telescope Science Institute in Baltimore, Md. The researchers created a series of theoretical models based on observations of debris disks around other stars, as well as the Jupiter-sized planets discovered so far.

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They found that only a fraction of the planetary systems out there have giant planets at the right locations to help create an asteroid belt of the right size. In fact, it looks like the Solar System might be rare and special when it comes to perfectly-sized asteroid belts.

“Our study shows that only a tiny fraction of planetary systems observed to date seem to have giant planets in the right location to produce an asteroid belt of the appropriate size, offering the potential for life on a nearby rocky planet,” said Martin, the study’s lead author. “Our study suggests that our solar system may be rather special.”

There are three potential models for asteroid belt formation in other star systems.

A Jupiter-sized world migrates slowly inward, disrupting the asteroid belt before it can really form. All the potential asteroids are consumed or flung out into deep space. A potential Earthlike world is deprived of the chemicals (and catastrophic incentive) to evolve complex lifeforms. That’s bad

No large Jupiter-sized world forms at all, allowing the solar system to create a massive asteroid belt. Material from this enormous asteroid belt would be too punishing to Earthlike worlds for complex life to stand a chance. Also bad.

A Jupiter-sized world forms in the outer solar system, and only moves in a little, preventing an overly large asteroid belt from forming. There are still enough asteroids out there to seed an Earthlike world with chemicals and evolutionary encouragement, but not enough to set its progress back. That’s us! …

via You Need Just the Right Amount of Killer Asteroids to Promote Complex Life.

4 thoughts on “You Need Just the Right Amount of Killer Asteroids to Promote Complex Life

    1. Xeno Post author

      “… all three kinds of molecules needed to form living cells have now been found in meteorites and appear to have been made there… :

      Nucleobases, used to form nucleic acids that make up genetic material such as DNA. Amino acids, used to build proteins. Amphiphilic compounds — which are attracted to water on one end and to oil on the other — that are used to build cell membranes. … meteorites may have served as a molecular kit providing essential ingredients for the origin of life on Earth and possibly elsewhere.”

      1. jim carlin

        i thought that was accurate
        and certainly could have accelerated the process
        we really live in a magnificant universe:)

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