With family wealth to back him, he founded an observatory in the western dark-sky desert of the U.S. and hoped to unlock the mystery of the Red Planet. He soon became fascinated by another cosmic ...

Feb. 18 marks the 95th anniversary of the discovery of our outermost planet-not-planet. Here's what to know about the short life of what was, for a single human lifetime, the solar system's ...

The ringed gas giant Saturn has officially replaced Jupiter as the planet in our solar system with the most moons. The International Astronomical Union officially recognized 128 new moons orbiting ...