rocky worlds like our own are abundant in our galaxy. — Alien landscapes: 15 places on Earth that look exoplanetary — Planet classification: How to group exoplanets — 10 weird water worlds ...

Their results, published in The Astronomical Journal this week, suggest that an Earth-like planet orbits one in every four sun-like stars. Totaled up, that means there could be up to 10 billion ...

NASA has identified 10 planets orbiting ... the surface of a rocky planet. "The Kepler data set is unique, as it is the only one containing a population of these near Earth-analogs – planets ...

In the cold, dark outskirts of planetary systems far beyond the reach of the known planets, mysterious gas giants and ...

Earth has four seasons, but do other planets in our solar system also have hot summer days and cold winter nights?

Now astronomers have detected the ruins of ancient planets around two unusual white dwarf stars, including an Earth-like world that existed almost 10 billion years ago. When most stars ...