Presence of Asteroid Belts & Gas Giants In Systems Key to Finding Extra-Solar Life

Image: NASA/JPL-Caltech

According to the theory of punctuated equilibrium, evolution will go faster when life has to make rapid changes to survive in challenging environments. Life with an asteroid belt in system can be quite varied and dramatic. Multi-cellular life might need an asteroid belt to provide the right number of hits to spur on evolution.

Only a fraction of the exoplanets found have asteroid belts in their system, indicating that life could be less common as previously estimated. The scientists published their findings in the journal Monthly Notices of the Royal Astronomical Society.

Astronomers have hypothesized that the asteroid belts situated between Jupiter and Mars, are necessary to life. As the Solar System formed, gravitational forces would have pulled clumps of matter towards the inner solar system. This asteroid belt lies on the snow line, where materials like water stay frozen but if they move closer in, they melt.

The tidal forces at work between Jupiter and Sol would have torn apart the asteroid belt’s materials, preventing further planet forming and leaving behind only a smaller belt, which has 1% of the mass.

The asteroids would have bombarded the planets of the inner Solar System, providing the raw materials, like water, that are essential to carbon-based life. It also gave evolution a quick start by drastically changing the Earth’s climate and environment.

There are currently 90 stellar systems with an asteroid belt. In every case, the belts are located where the astronomers predicted they would be.

If gas giants had formed but not shifted slightly, as Jupiter did, then the asteroid belt would be so full of large objects that the inner planets would have been bombarded too frequently for life to take hold. If the gas giant moved inwards, it would have absorbed most of the asteroid belt.

According to the astronomers, only 4% of exoplanet systems have the right setup to support the evolution of advanced carbon-based life.

This illustration shows three possible scenarios for the evolution of asteroid belts. In the top panel, a Jupiter-size planet migrates through the asteroid belt, scattering material and inhibiting the formation of life on planets. The second scenario shows our solar-system model: a Jupiter-size planet that moves slightly inward but is just outside the asteroid belt. In the third illustration, a large planet does not migrate at all, creating a massive asteroid belt. Material from the hefty asteroid belt would bombard planets, possibly preventing life from evolving.
(Credit: NASA/ESA/A. Feild, STScI)

[via Wired]

Author: range

I'm mathematician/IT strategist/blogger from Canada living in Taipei.

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