Jupiter May Have Destroyed Super-Earths in Our Solar System By Shooting Asteroids at Them

Monday, 23 March 2015 - 4:44PM
Astrophysics
Solar System
Earth
Monday, 23 March 2015 - 4:44PM
Jupiter May Have Destroyed Super-Earths in Our Solar System By Shooting Asteroids at Them
Did Jupiter kill several Earth-like planets in our solar system by shooting asteroids and proto-planets at them? A new study claims that, when our solar system first came into existence, Jupiter's early spin may have had a wrecking ball effect and destroyed several young planets.

The researchers' study was borne out of the observation that our solar system doesn't follow the same pattern of planetary formation as other solar systems. The more exoplanets we discover, the more we see that most star systems have several rocky planets that are closer to the Sun than Mercury. "Our solar system is looking increasingly like an oddball," study co-author Gregory Laughlin said in a statement.

"The fact that the default mode of planet formation ... is leading to configurations that are totally unlike our own solar system is something I found really curious," Laughlin told Discovery News"The main feature of our solar system is that the inner part is just missing."

This anomaly led the research team to the Grand Tack hypothesis, which asserts that in the first 1-10 million years of our solar system's existence, Jupiter spiraled inward towards the Sun, and its massive gravitational pull sent asteroids and proto-planets careening in every direction, creating massive carnage in the inner solar system and ultimately destroying all of the Earth-like planets that were closer to the Sun. Eventually, the entire Solar System would have been destroyed and spun into the Sun if it weren't for the formation of Saturn, which counteracted Jupiter's gravitational pull.

This hypothesis has been around for a while, but the researchers used computer models in order to simulate the conditions of the early Solar System and test the theory's plausibility. They found that the conditions were conducive to the utter destruction of our inner solar system, as the extremely violent collisions would have occurred at 5 km per second. These collisions would have led to more planetary fragments, which would have led to more collisions exponentially. 

"If our solar system had started out as a normal, standard-issue solar system, it shows that the Grand Tack could have very handily kind of wiped the slate clean and destroyed any planets that originally were interior to Mercury's orbit," Laughlin said.

The researchers recognize that the Grand Tack hypothesis is still just a theory, but if their findings turn out to be correct, then it would have enormous implications for our search for Earth-like planets and extraterrestrial life. It would demonstrate that Jupiter-like gas giants and inner super-Earths are mutually exclusive, and that a planet like Earth would require a Saturn-like planet to form, which would make finding a planet precisely like Earth that much more unlikely. 

Lead author Konstantin Batygin told Space.com, "While Earth-mass planets may indeed be plentiful in the galaxy, truly Earth-like planets, with low atmospheric pressures and temperatures on the surfaces, are likely an exception to the rule."
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