The announcement, made today by Mike Brown of Caltech, came just hours after another newfound object, one slightly smaller than Pluto, was revealed in a very confusing day for astronomers and the media.
The new object, temporarily named 2003 UB313, is about three times as far from the Sun as is Pluto.
"It's definitely bigger than Pluto," said Brown, a professor of planetary astronomy. The object is round and could be up to twice as large as Pluto, Brown told reporters in a hastily called
NASA-run teleconference Friday evening.