Alien planet count tops 700 distant worlds

NASA/JPL-Caltech

NASA's Kepler mission has discovered a world where two suns set over the horizon instead of just one. The planet, called Kepler-16b, is not thought to be habitable. It is a cold world, with a gaseous surface, and it circles two stars, just like "Star Wars" Tatooine.

By Mike Wall

Less than 20 years after discovering the first world beyond our solar system, astronomers have bagged alien planet number 700.

As of Nov. 18, the tally stands at 702 exoplanets, according to the Extrasolar Planets Encyclopedia, a database compiled by astrobiologist Jean Schneider of the Paris-Meudon Observatory.

Schneider's list is one of two main alien-world trackers out there. The other is called "PlanetQuest: New Worlds Atlas," run by NASA's Jet Propulsion Laboratory. PlanetQuest's current count stands at 687; the difference between the two databases highlights the uncertainties involved in exoplanet detection and confirmation.

Regardless, both tallies have been growing quickly lately. And both will add hundreds, or perhaps thousands, of new alien planets in the near future. More >