Discover the cosmos! Each day a different image or photograph of
our fascinating universe is featured, along with a brief
explanation written by a professional astronomer. 2005 July 31
Explanation: Is that a tenth planet? A faint, slowly moving dot
discovered by computer shows clear signs of being a deep Solar
System object at least as large as Pluto. The object, designated
2003 UB313, is currently situated nearly 100 times the Earth-Sun
distance -- over twice the average Pluto-Sun distance. That far
out, the only way a single round object could be as bright as
2003 UB313 would be if it is at least as large as Pluto and
completely reflective. Since 2003 UB313 is surely not completely
reflective, it could be substantially larger. One of the
discovery frames is shown above digitally expanded and
artificially brightened. 2003 UB313 was identified initially on
frames taken by the automated 1.2-meter Samuel Oschin Telescope
at Palomar Observatory> in California, USA. Authors & editors:
NASA Web Site Statements, Wa