Mercury has the shortest and fastest orbit around the Sun and experiences dramatic temperature changes as it rotates. It is a world of extremes. Explore facts about our solar system's fastest planet.

Microsoft and our third-party vendors use cookies to store and access information such as unique IDs to deliver, maintain and improve our services and ads. If you agree, MSN and Microsoft Bing ...

Staring at the sun—a close (but safe) look at our home star Staring at the sun—a close (but safe) look at our home star Need a new idea to keep kids entertained? Try stargazing. Need a new ...

Seven planets currently form a rare "planet parade" in February's evening sky, with three easy to see with the naked eye, and ...