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.
