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.
Our solar system may be an oddball in the universe. A new study using data from NASA's Kepler Space Telescope shows that in most cases, exoplanets orbiting the same star have similar sizes and regular spacing between their orbits.
The agency will hold a news conference Thursday (Dec. 14) at 1 p.m. EST (1800 GMT) to reveal a new discovery made by its prolific Kepler space telescope, which has been searching the heavens for alien worlds since 2009.