It doesn't mean all are potentially habitable, but the sheer number of Earth-size planets is a welcome starting point in the search for worlds like our own.
Scientists have yet to find a twin Earth -- one that's not only the right size but also located in the so-called Goldilocks zone, a place that's not too hot and not too cold where water might exist in liquid form.
Two independent groups came up with the new estimate after a fresh analysis of data gathered by NASA's Kepler spacecraft, which was launched in 2009. One team was from the Harvard-Smithsonian Center for Astrophysics; the other from the University of California, Berkeley and University of Hawaii.
More Nation & World Headlines
Arby’s disciplines workers who refused to serve cop Falling SAT scores prompt alarm over high schools Stephen Colbert, Jeb Bush are in social media feud over tickets Kentucky clerks to license marriages as their boss is jailed Saudis seek to reload arsenal with Boeing bombs French confirm wing part is from missing Malaysia 777 Donald Trump vow to GOP: No third-party bid S. Carolina church shooting suspect to face death penalty
Our new comment system is not supported in IE 7. Please upgrade your browser here.