February 15, 2013

“No Jupiter, No Advanced Life? ” (Today’s Most Popular)

What are the implications of a star systems missing a massive gas giant such as our Solar Systems’Jupiter –it could imply conditions of massive bombardment from comets and asteroids that would prevent the development of advanced life.

The artist’s impression below of the debris disc and planets around the star known as Gliese 581, superimposed on Herschel PACS images at 70, 100 and 160 micrometre wavelengths. The line drawing superimposed on the Herschel image gives a schematic representation of the location and orientation of the star, planets and disc, albeit not to scale. GJ 581’s planets have masses between 2 and 15 Earth masses and are all located within 0.22 Astronomical Units (AU, where 1 AU is the distance between Earth and our Sun) of the central star. Minus a Jupiter-like gas giant, a vast debris disc extends from approximately 25 AU to 60 AU.

Two NASA astronomers recently suggested that the size and location of an asteroid belt, shaped by the evolution of the sun’s planet-forming disk and by the gravitational influence of a nearby giant Jupiter-like planet, may determine whether complex life will evolve on an Earth-like planet.

Rebecca Martin, a NASA Sagan Fellow from the University of Colorado in Boulder, and astronomer Mario Livio of the Space Telescope Science Institute have concluded that Solar systems with life-bearing planets may be rare if they are dependent on the presence of asteroid belts of just the right mass.

Asteroids may have delivered water and organic compounds to the early Earth. According to the theory of punctuated equilibrium, occasional asteroid impacts might accelerate the rate of biological evolution by disrupting a planet’s environment to the point where species must try new adaptation strategies. The astronomers based their conclusion on an analysis of theoretical models and archival observations, including infrared data from NASA’s Spitzer Space Telescope.

“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.”

Read more: "No Jupiter, No Advanced Life? " (Today's Most Popular) — The Daily Galaxy.

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