Astronomers studying 35 NASA Hubble Space Telescope (HST) images of the solar system's farthest known object, unofficially named Sedna, are surprised the object does not appear to have a companion ...

The astronomers who discovered Sedna were so certain that a satellite accompanied the object that when they announced its existence, they released an artist’s rendition of the supposed moon. It ...

Planetary scientists continue to debate what Sedna’s presence says about the history of our solar system. Now, S. Alan Stern of the Southwest Research Institute in Boulder, Colorado, says large bodies ...

Scientists say they have found the first example of a new breed in the solar system's menagerie: a planetoid that spends all its time far beyond Pluto, in a chilly region that was once thought to be ...

Object 90377 Sedna — a distant trans-Neptunian object known best for its highly elliptical, 11,390-year-long orbit — is currently on its way towards perihelion (its closest approach to the Sun) in ...

Caltech astronomers have discovered the most distant known object in the solar system, a frigid, near-planet-sized body of rock and ice that is now three times as far from the sun as Pluto. The ...

Astronomers have detected what could be the Solar System's 10th planet. It was first seen by astronomers using California's Palomar Observatory, and has been given the name "Sedna" after the Inuit ...

Pictures of the newly discovered planetoid Sedna show it moonless, spinning alone some 8 billion miles from Earth. Sedna, though, still might have a moon that was hiding somewhere or too dark to be ...

The distant planetoid Sedna appears to be covered in a tar-like sludge that gives it a distinctly red hue, a new study reveals. The findings suggests the dark crust was baked-on by the Sun and has ...

One of Pluto's distant neighbors just got downsized: According to new observations, the remote object known as Sedna is even smaller than previously believed. When astronomers discovered Sedna in 2003 ...

A probe will be sent to investigate Pluto - a planet or not Astronomers are to rethink the system for classifying planets following the discovery of what some claim is the 10th in the Solar System. A ...