Did solar system once have fifth giant?

The solar system could once have had a fifth giant planet, which got hurled out into space billions of years ago.

The diamond as big as a planet

It's a long way to go, but it could be worth it: most of the rocks on an odd gas giant 1,200 light years away could be made of diamond, astronomers say.

Youngest exoplanet discovered - and it grew up fast

Images of an alien planet passing in front of its sun have demonstrated that gas giants can form very quickly.