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

Today, it’s believed that Jupiter and Saturn, the largest planets, were the first to fully form, both within a few million years. Uranus and Neptune were next, within 10 million years.

While all this was happening, the smaller planets inside the ice line were forming too. But with less raw material to work with, Mercury, Venus, Earth and Mars took much longer. Today, it’s believed ...

(The Conversation is an independent and nonprofit source of news, analysis and commentary from academic experts.) Are planets in the solar system that are closer to the Sun older than the ones ...