A new study has revealed that Jupiter may have destroyed Solar System's first generation of Earth-like planets.
A new study has revealed that Jupiter may have destroyed Solar System's first generation of Earth-like planets.
Long before Mercury, Venus, Earth, and Mars formed, it seemed that the inner solar system may have harboured a number of super-Earths planets larger than Earth but smaller than Neptune. If so, those planets are long gone, broken up and fallen into the sun billions of years ago largely due to a great inward-and-then-outward journey that Jupiter made early in the solar system's history.
This possible scenario has been suggested by Konstantin Batygin, a Caltech planetary scientist, and Gregory Laughlin of UC Santa Cruz. The results of their calculations and simulations suggested the possibility of a new picture of the early solar system that would help to answer a number of outstanding questions about the current makeup of the solar system and of Earth itself.
For example, the new work addressed why the terrestrial planets in the solar system have such relatively low masses compared to the planets orbiting other sun-like stars.
Batygin noted that when Jupiter tacked around, some fraction of the planetesimals it was carrying with it would have calmed back down into circular orbits. Only about 10% of the material Jupiter swept up would need to be left behind to account for the mass that now makes up Mercury, Venus, Earth, and Mars.
From that point, it would take millions of years for those planetesimals to clump together and eventually form the terrestrial planets, a scenario that fits nicely with measurements that suggest that Earth formed 100–200 million years after the birth of the sun.
Since the primordial disk of hydrogen and helium gas would have been long gone by that time, this could also explain why Earth lacks a hydrogen atmosphere.
The paper also suggested that the formation of gas giant planets such as Jupiter and Saturn, a process that planetary scientists believe was relatively rare, plays a major role in determining whether a planetary system winds up looking something like our own or like the more typical systems with close-in super-Earths.
The study is published in the Proceedings of the National Academy of Sciences (PNAS).
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