Today, it’s believed that Jupiter and Saturn, the largest planets, were the first to fully form, both within a few million ...

NASA/Caltech/R. Hurt (IPAC), CC BY Our solar system is a particularly crowded place. Millions of objects move within it, whether they are planets, moons, comets, or asteroids. And every year, we ...

Some became rocks the size of baseballs, others the size of a house, and a few as big as a planet. This process, called accretion, is how everything in the solar system – planets, moons ...