Pluto and the Kuiper Belt

Objects beyond the orbit of Neptune, including Pluto and its moon.

Kuiper Belt objects (KBOs) orbit relatively near the plane of the orbits of the planets.

The definition of a "planet" and the controversy over the status of Pluto

Dec 4, 2010
"Here's part 2 of our conversation with astronomer Mike Brown. Yesterday, he talked about the latest findings on Eris, the Haumea controversy and more; today he talks about being known as the 'killer' of Pluto, his reflections on Brian Marsden and his hopes for the New Horizons mission to Pluto."
Nov 29, 2010
"Planetary scientist Alan Stern has been fighting for Pluto's planethood ever since the icy body was demoted to "dwarf planet" in 2006."
Nov 20, 2010
"Now that Pluto looks to have regained the title of largest object in the outer solar system, should astronomers consider calling it a full-fledged planet again?"
Nov 12, 2010
"On November 6, 2010, the dwarf planet Eris occulted a faint 16th magnitude star and this was the first time astronomers were able to witness an occultation by Eris"
Nov 8, 2010
New stellar occultation measurements indicate that the dwarf planet Eris is in fact slightly smaller than Pluto
Oct 29, 2010
"The reddish hue of objects in our solar system's outer reaches may be evidence of complex organic molecules, perhaps even the building blocks of life, researchers say."
Oct 28, 2010
"The dwarf planet Eris has been found to have a surface much like Pluto's and still harbors surprises five years after its discovery."
Oct 8, 2010
"Diversity of objects and frequency of those in pairs not easily generated by standard models of planet formation."
Oct 6, 2010
"Eris — that pesky big dwarf planet that caused all the brouhaha about planets, dwarf planets, plutoids and the like — has gotten a closer look by a team of astronomers from several different universities, and guess what? Eris and Pluto have a lot in common."
Jul 11, 2010
"It's possible that if we do eventually observe the hypothetical objects that make up the hypothetical Oort cloud, they will all be a deep red color."