WASHINGTON (March 15) - A newly discovered dark and frigid world, a bit smaller than Pluto and three times farther away, has emerged as the most distant object in the solar system, astronomers said on Monday.  The new "planetoid," named Sedna after an Inuit goddess who created the sea creatures of the Arctic, is by far the coldest and most distant object known to orbit the sun, a team of researchers announced.

At more than 8 billion miles from the sun, the temperature on Sedna never gets above minus 400 degrees Fahrenheit.

"The sun appears so small from that distance that you could completely block it out with the head of a pin," said Mike Brown, an astronomer at California Institute of Technology, who led the research team.