An Earth-like planet with water, sufficient atmosphere to sustain life and orbiting in a habitable zone next to its parent star may nevertheless be at a distinct disadvantage if it has giant neighbors.
At least according to astronomers at New York University Abu Dhabi who joined NASA’s Jet Propulsion Laboratory scientists. Together, they analyzed and studied 147 extra-solar planetary systems with known giant planets.
Our own planet Earth has been doing just fine for billions of years despite the fact that our solar system has not one, two, three but four gas giant neighbors – Jupiter, Saturn, Uranus, and Neptune. But it seems Earth has been lucky and defied the odds for maintaining a stable habitable zone.
The Effects of Giant Neighbors on Smaller Planets
The reason giant planets can negatively affect smaller, rocky planets is that the enormous gravity of behemoth sister-worlds bear the potential to destabilize the orbits of the minor planets. Data suggests that the presence of a giant world shrinks the habitability zone for smaller planets.
But Earth’s habitability chances seem to have significantly benefited from the presence of Jupiter and Saturn. For one, these gas giants have prevented an uncounted number of dangerous asteroids from entering into Earth-orbit territory. That means far fewer chances of a catastrophic asteroid collision with our planet.
Jupiter and the other gas giants in our solar system act like “vacuum cleaners”. Namely, they capture and absorb a lot of destructive planetoids that might otherwise have had a shot at Earth. Obviously, not all destructive asteroids, comets, and meteors are caught. Earth has had to endure some huge impacts, including the one that wiped out dinosaurs some 66 million years ago.
On balance, however, planetary scientists say that data on exo-planet habitability chances is clear. The presence of giant neighboring planets is a net disadvantage for stellar systems that might have otherwise supported a long-term habitable zone.
A paper with the detailed study findings is available in The Astrophysical Journal.
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