The number of planets that orbit the sun depends on what you mean by “planet,” and that’s not so easy to define ...

Planet demographics reveal a puzzling lack of worlds in a certain size range throughout the galaxy F or centuries our solar ...

Astronomers for the first time have deciphered the three-dimensional structure of the atmosphere of a planet beyond our solar ...

Around the galaxy exist stars that have been given a push, and orbit much faster than the vast majority of their stellar ...

Feb. 18 marks the 95th anniversary of the discovery of our outermost planet-not-planet. Here's what to know about the short ...

Many of the new planets have a "new terrain system" and that allows for truly towering mountains and even "oceans that can be several kilometers ... planet but it's the size of a real planet?" ...

A planet-size object that possibly once visited the ... (One AU is approximately 93 million miles, or 150 million kilometers, roughly the average distance from Earth to the sun.) ...