Are planets in the solar system that are closer to the Sun older than the ones further away? – Gavriel, age 10, Paducah, Kentucky A cloud of collapsing gas created our Sun, the first thing to form in ...

To better understand why the planets have variable compositions, we have to first understand the process of how stars form. While the composition of gas and dust in a precursor molecular cloud is ...

When you buy through links on our articles, Future and its syndication partners may earn a commission.

Discover why the solar system's planets are arranged as they are, shaped by formation conditions and planetary migration.

When I was a kid, there were nine planets. Now we know of thousands! But that includes exoplanets, alien worlds that orbit alien suns. Only eight planets call our solar system home. Or there might ...