An alien planet orbits a star other than our sun, and is sometimes called an "exoplanet." Learn more about the types of alien planets, including exoplanets and extrasolar planets, and get the latest news.
Scientists on NASA's New Horizons mission, which performed the first-ever flyby of Pluto in July 2015, will officially propose a new definition of "planet" next month — one that gives Pluto its planethood back.
Astronomers have never seen anything like this before: Seven Earth-size alien worlds orbit the same tiny, dim star, and all of them may be capable of supporting life as we know it, a new study reports.
NASA unveiled the winners of its space poop challence, life's building blocks were found on the dwarf planet Ceres and an Indian rocket launched a record-breaking 104 satellites to orbit. Here are the most interesting things that happened this week.