Jupiter & Saturn: Destroyer and Protector?
Our solar system is weird.
First of all, it doesn’t look much like other ones we’ve been finding. A lot of those have Jupiter-size giant planets orbiting very close in to their parents stars (“hot Jupiters”), closer even than Mercury orbits the Sun. By contrast, our Jupiter orbits the Sun much farther out, more than a dozen times Mercury’s distance from the Sun.
Worse, a lot of these other solar systems are compact. They have several planets orbiting close in to their star, and these planets tend to be “super-Earths,” bigger than our home world but smaller than Neptune. They probably have thick atmospheres, too. A good example of this is Kepler-11, which has six planets that orbit their star inside the size of Venus’ orbit.
So why are we so different than everyone else? The answer may be: Jupiter. A new paper has been released that points an accusatory finger at our solar system’s largest world. Ours may have looked a lot like all the others we’ve seen, but Jupiter came along and wiped it out, setting the stage for what see today: lower mass worlds like ours close in, and bigger ones farther out.
So, it seems that Jupiters’ reign of destruction in the inner disc was arrested by the growth of Saturn. Saturn and Jupiter interacted, resulting in the slow return of Jupiter to its current orbit, leaving the inner disc free to create planets with what matter was left. Which also explains why the inner planets are a good bit smaller than the ‘super-earths’ we see in other systems.
Later: A friend asked: “I wonder if anyone has thought about linking the idea to the Fermi paradox”
Good point, I’d suspect it would make a big difference. Could explain why we’ve seen no sign of other civilisations yet…