Dangit, Jupiter. Or maybe thanks? I’m not sure how to feel about this one. According to a study published this week in the Proceedings of the National Academy of Sciences, our solar system may once have been populated by a whole different set of planets than the ones we know now. And then Jupiter obliterated them.
Led by Konstantin Batygin (a Caltech planetary scientist) and Gregory Laughlin of the University of California, the new study suggests that certain quirks seen in our solar system could be explained by Jupiter coming in like a wrecking ball and smashing its original planetary companions to smithereens.
Batygin and Laughlin are looking for an explanation as to how our solar system got to be its own special self. As planetary scientists have gotten to examine more and more neighboring systems, they say, it’s become clear that our own is a little different.
“Indeed, it appears that the solar system today is not the common representative of the galactic planetary census. Instead we are something of an outlier,” Batygin said in a statement. The absence of planets between Mercury and the Sun is especially perplexing. It seems that it’s more typical for solar systems to have a few super-Earths (planets a few times larger than ours) close to the host star.
“But there is no reason to think that the dominant mode of planet formation throughout the galaxy should not have occurred here. It is more likely that subsequent changes have altered its original makeup,” Batygin said.
A few years ago, researchers proposed something called the Grand Tack theory. The idea is that Jupiter got pulled toward the sun after its formation, caught up in the pull of interplanetary dust. When it caught up with Saturn, the two planets pulled each other back to their current positions.
The researchers who came up with Grand Tack proposed that Jupiter’s slow pull through the solar system would have disturbed the position of the asteroid belt, as well as making Mars smaller than it should be by hogging and displacing planet-building materials.
The new study takes this theory a step further by calculating what would happen to the kind of planets that should be orbiting just around our sun if Jupiter made this trek.
Based on their calculations, they think Jupiter could have done those planets in. The massive gas giant would have messed with the orbits of all of the not-quite-planets forming in the life-giving dust of the early solar system. Once a couple of the unwieldy space rocks collided, it would cause a chain reaction of destruction. And based on simulations using the dimensions of a known super-Earth, the researchers believe that any planets in Jupiter’s wake would be crushed by the onslaught of debris after just 20,000 years.
“It’s the same thing we worry about if satellites were to be destroyed in low-Earth orbit. Their fragments would start smashing into other satellites and you’d risk a chain reaction of collisions. Our work indicates that Jupiter would have created just such a collisional cascade in the inner solar system,” Laughlin said in a statement.
From there it would have been a pretty quick trip into the sun for total annihilation. Our own planet and its rocky neighbors would have been born from the planetary ashes of the dead giants.
“Jupiter’s ‘Grand Tack’ may well have been a ‘Grand Attack’ on the original inner solar system,” Laughlin said.
