Very interestingly, they found that systems with fewer planets tend to exit their “ejection” phase after about 100 million years, but systems with 10 planets are still unstable even after a billion years. They also found that these more bountiful systems actually eject the majority of their planets, losing 70 percent after a billion years. Most of the ones ejected are lower-mass, as expected.

Wonder how many sibling planets we had when our solar system first formed. This sort of topic is always fascinating to me.