Add Yahoo as a preferred source to see more of our stories on Google. Jupiter is already the biggest planet by far in our solar system, but new research suggests it was somehow once even larger than ...

This article was originally featured on The Conversation. 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 ...

Astronomers have discovered more than 300 exoplanetary systems that have three or more known planets. Most of these planets are about the same size and spaced close together, earning them the moniker ...

Our solar system may have a ninth planet after all, researchers say. The possibility that an additional planet may be hidden far into the solar system was touted more than a century ago. But ...

When you see art of our solar system as the planet orbit the sun, you may notice that Earth's orbit has a tilt. It is not a perfect circle. What's more, Earth is not the only planet that displays such ...

On August 24, 2006, our solar system lost a planet. It wasn't by cataclysmic destruction, but rather by the vote of the International Astronomical Union, which declared that Pluto, considered the ...

Beyond that, in the decades to come, we might be able to see the colours of an exoplanet’s surface, and determine if plant life might be present there. And then we can search for changes in a planet’s ...