The discoverers of the tenth planet are Michael E. Brown (Caltech), Chad Trujillo (Gemini Observatory), and David Rabinowitz (Yale University). They first imaged the object on October 21, 2003, but didn’t see it move in the sky until reimaging the same area 15 months later on January 8, 2005. They announced the discovery on July 29, 2005.

1. Christa Says:
   September 12th, 2005 at 9:51 am

   Are you really Sure that there is a tenth planet???

   Christa Daniels