Were It Not for Cosmic Good Fortune, We Wouldn’t Be Here

Who doesn’t want the trains to run on time? When stuff runs like clockwork, we’re happy. And thankfully, that’s how the planets orbit the sun: dependable, and always on time. But it wasn’t always like this. Scientists suspect the solar system, some time in its early years, underwent a violent seismic shift. The orbits of the gas giants—Jupiter and Saturn—got tweaked big time, and the aftershocks affected all the planets, including Earth and Mars, as well as the asteroid and Kuiper belts.

In our new , published in we rewrite the origins of this massive shift—called a “dynamical instability”—and explain how everything in the solar system today found its place. What’s more, our idea is broadly applicable and may