Two massive planets may have once existed in early solar system before being ejected, leaving behind evidence in unusual ...

Add Yahoo as a preferred source to see more of our stories on Google. (Ianm35/iStock/Getty Images Plus) The Solar System is one of the comforting constants of human existence. No matter what else we ...

As the United States prepares to celebrate its 250th anniversary, the history of the solar system tells its own story of ...

A Jupiter-size exoplanet orbiting a dead star baffled astronomers. But the planet named WD 1856 b could preview the fate of ...

So far, humanity has yet to find its first "exomoon"—a moon orbiting a planet outside of the solar system. But that hasn't been for lack of trying. According to a new paper by Thomas Winterhalder of ...

An object eight times the mass of Jupiter may have swooped around the sun, coming superclose to Mars' present-day orbit before shoving four of the solar system's planets onto a different course. When ...