This article was originally published at The Conversation. The publication contributed the article to Space.com's Expert Voices: Op-Ed & Insights. The size of the solar system is defined by the volume ...

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 ...

Our solar system is a smashing success. A new study suggests that from its earliest period—even before the last of its ...

A new study suggests yet another theory for a possible extra planet in our solar system, likely of a size between Mercury and ...