A surprising chemical difference between Pluto and Sedna, another dwarf planet in the distant Kuiper Belt, is helping scientists nail down their respective masses, a new study reports. "Kuiper Belt ...

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 ...

The discovery of a nearly Pluto-sized object way out beyond the known worlds could jeopardize the status of Pluto as a planet, adding fresh fuel to an argument among astronomers that is likely to last ...

Our corner of the galaxy got a little stranger this week with the discovery of Sedna, the most distant object ever spotted in the solar system. Now astronomers are puzzling over how it got there. The ...

While for most people Pluto is the most distant planet in the Solar System, things get a lot more fuzzy once you pass Neptune and enter the realm of trans-Neptunian objects (TNOs). Pluto is probably ...

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 ...

Astronomers have glimpsed an icy red-tinged planetoid three times as far from the sun as the planet Pluto, making it the most distant orbiting object discovered in the solar system. "The morning I ...

“The Sun appears so small from that distance that you could completely block it out with the head of a pin,” said Dr. Mike Brown, California Institute of Technology, Pasadena, Calif., associate ...

Recent spectroscopic studies of infrared light reflected from the surface of Sedna reveal that it is probably unlike Pluto and Charon since Sedna’s surface does not display evidence for a large amount ...

January 5, 2005, is an astronomical anniversary that is not really marked but should be. It saw the discovery of dwarf planet ...

Space is infinite and so are its wonders, as shown by the announcement of the discovery of icy-cold Sedna, a planetoid three times farther away from the sun than even lonesome Pluto. Sedna, named for ...

In the frozen outskirts of the solar system, a reddish dwarf planet orbits in silence. Known as Sedna, it is so distant that one trip around the Sun takes more than 11,000 years. For much of that time ...