Saturn is essential for the Grand Tack theory. If there was no Saturn, Jupiter would have stayed close in near the Sun, and some of the super-Earths would have survived, making our solar system just like all those exoplanetary systems out there.
That’s a pretty sweet explanation of how our solar system came to be so unusual. But is the Grand Tack theory right?
Only time – and observational-data-confirming-or-rejecting-testable-predictions – will tell.