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Scientists: An epic migration by Jupiter led to destruction of "super-Earths"

The planet-shattering journey laid foundations for Earth, they say

CNN  — 

It turns out that Jupiter may be more than just an enormous ball of gas spinning a few hundred million miles farther out in the solar system.

We earthlings might have the giant planet to thank for our very existence.

Two scientists are suggesting that the inner solar system once played host to a bunch of “super-Earths” – planets that were larger than our own but smaller than Neptune.

Jupiter, however, put an end to those early occupiers of the inner orbits, bulldozing in and sweeping them into the sun, according to a paper published this week in the Proceedings of the National Academy of Sciences.

Jupiter’s epic, planet-shattering journey toward the sun and back out again laid the foundations for the creation of Earth and the other smaller planets nearby – Mercury, Venus and Mars.

“Our work suggests that Jupiter’s inward-outward migration could have destroyed a first generation of planets and set the stage for the formation of the mass-depleted terrestrial planets that our solar system has today,” said Konstantin Batygin of Caltech, one of the authors of the paper.

Galactic outlier

The theory attempts to explain why our solar system is a bit of an oddball in our galactic neighborhood.

Most other systems that have planets orbiting around a star similar to our sun look very different. They generally have at least one planet significantly larger than Earth that’s in a closer orbit than Mercury’s. But they don’t have many objects farther out.

Maybe that’s because of Jupiter’s destructive romp in the early history of the solar system.

“There is no reason to think that the dominant mode of planet formation throughout the galaxy should not have occurred here,” Batygin said. “It is more likely that subsequent changes have altered its original makeup.”

He and his co-author – Gregory Laughlin of University of California, Santa Cruz – are building on a scenario of Jupiter’s migration that was previously put forward by other scientists.

Dance with Saturn

Known as the Grand Tack scenario, it describes Jupiter getting drawn toward the sun in the early era of the solar system thanks to its huge mass.

What stops it from being sucked right into the sun is Saturn. The two gas giants start to exert gravitational influence on one another, entering a planetary dance that eventually sends them back farther out into the solar system.

Batygin and Laughlin suggest that during its inward journey, Jupiter dragged a load of planetary building blocks, known as planetesimals, along with it.

That sent the planetesimals smashing into debris in the inner solar system, causing them to break apart and fall into the sun at a faster rate.

Swept into the sun

The scientists say they ran a simulation of what would happen if there were also a number of super-Earths in the vicinity as well.

They found that a wave of decaying planetesimals would steer the super-Earths into the sun over the course of 20,000 years.

“It’s a very effective physical process,” Batygin said. “You only need a few Earth masses worth of material to drive tens of Earth masses worth of planets into the sun.”

On its way back out, Jupiter left some remaining planetesimals in its wake – the building blocks that over millions of years would come to form Earth, Mercury, Venus and Mars.