Add Yahoo as a preferred source to see more of our stories on Google. Digital art of distant planet - Dottedhippo/Getty Images On August 24, 2006, our solar system lost a planet. It wasn't by ...

All of our solar system’s planets are lining up in the night sky at once this week. This extraordinary celestial event will see the sky scattered with seven visible planets in what is known as a great ...

A scale model of the solar system, with each planet depicted in relief on individual square granite markers installed atop concrete bases embedded in the ground. Each planet bears a laser etched ...

Mercury, Venus, and Mars sit within the same general neighborhood as Earth, yet each has followed a radically different path.

Astronomers are closing in on one of the most tantalizing possibilities in planetary science, evidence that a previously unknown world may be lurking in the outer reaches of the solar system. The ...

A new study has proposed the existence of Planet Y, an alternative Planet Nine candidate that is smaller and closer to Earth than the hypothetical Planet X, which astronomers have been hunting for ...