03 August 2011, 05:47 PM ET
The three worlds are likely dwarf planets, like Pluto and Eris.
22 July 2011, 03:44 PM ET
No more shuttles, Pluto has a new moon, Mars rover gets a landing site and more. Vote for the top space story of the week.
21 July 2011, 02:51 PM ET
Pluto's history is long and convoluted, packed full of drama and surprises.
20 July 2011, 04:45 PM ET
The New Horizons probe is slated to make a close flyby of Pluto in July 2015.
20 July 2011, 09:35 AM ET
The Hubble Space Telescope has discovered a tiny new moon around Pluto.
20 June 2011, 07:58 PM ET
It has been five years since Nix and Hydra, Pluto's tiny moons, were named. Mysteries still abound with the pair.
19 April 2011, 03:35 PM ET
Poisonous gas has been discovered in the atmosphere of the dwarf planet Pluto.
18 March 2011, 04:45 PM ET
NASA's New Horizons probe has reached the orbit of Uranus on its way to Pluto.
16 December 2010, 01:53 PM ET
A NASA Pluto probe may be slumbering at the moment, but it's still tearing through space at a blistering pace, closing in on the orbit of Uranus.
29 November 2010, 07:13 AM ET
Planetary scientist Alan Stern has been fighting for Pluto's planethood ever since the icy body was demoted to "dwarf planet" in 2006. He lays out the case for Pluto at SPACE.com.
19 November 2010, 03:20 PM ET
The astronomical community lost two longtime, eminent members this week when Brian Marsden and Allan Sandage passed away.
19 November 2010, 07:19 AM ET
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?
19 November 2010, 07:19 AM ET
Mike Brown is best known as the man who killed Pluto. The Caltech astronomer led the team that discovered Eris, leading to Pluto's demotion to "dwarf planet."
15 November 2010, 05:01 PM ET
Pluto was originally considered the ninth planet in Earth’s solar system, but was recently classified as a dwarf planet. Pluto’s orbit takes it through the Kuiper Belt.
09 November 2010, 01:15 PM ET
The dwarf planet Eris, once thought to be the largest body in the outer solar system, may actually be smaller than Pluto, observations suggest.
27 October 2010, 11:20 PM ET
The dwarf planet Eris has been found to have a surface much like Pluto's and still harbors surprises five years after its discovery.
07 October 2010, 07:51 AM ET
The frozen surface of the dwarf planet Eris looks a lot like that of its smaller neighbor Pluto, new research has found.
16 June 2010, 07:04 AM ET
Stargazers can see the two brightest dwarf planets, formerly the asteroid Ceres and the planet Pluto, in June.
29 April 2010, 12:33 PM ET
Mysterious bright and dark spots mottling the surface of Pluto could be tar and frost, scientists say.
18 April 2010, 04:16 AM ET
Rocket-launch industry executives, engineers and related enthusiasts at the 17th annual meeting of the Space Access Society appear ready to depend on commercial services.
27 February 2010, 06:08 AM ET
Jupiter, the largest planet in the solar system, is about to welcome a robotic visitor in the form of NASA’s New Horizons probe on Wednesday.
18 February 2010, 08:30 AM ET
Pluto was discovered 80 years ago today, and astronomers are still arguing over what it is.
16 February 2010, 10:22 AM ET
SDO on it's way, Falcon launch countdown, the colors of Pluto, head-on asteriod collision and cool images of craters on mars and the Orion Nebula.
04 February 2010, 01:49 PM ET
The Hubble Space Telescope has returned the most detailed images of Pluto ever taken.
04 February 2010, 11:12 AM ET
See the dwarf planet Pluto turn in this video based on images taken by the Hubble Space Telescope. They are most-detailed yet views of Pluto to date.
30 December 2009, 05:31 PM ET
New Horizons is closer to Pluto than it is to Earth.
23 December 2009, 12:22 AM ET
From snowfalls on Mars, to the polar craters of the moon, take a tour of the solar system’s chilliest spots.
28 September 2009, 08:55 AM ET
Water is all over the solar system and the rest of the galaxy. What's it mean to the search for life?
18 September 2009, 11:32 AM ET
What Hubble and its handlers will be observing over the coming year.
19 March 2009, 08:09 AM ET
Thousands of new exoplanets may need a new naming system.
16 March 2009, 10:06 AM ET
Pluto's status nowadays as a so-called plutoid and former planet may be official in the latest textbooks, but someone forgot to tell the astronomers.
04 March 2009, 05:05 PM ET
An in-depth study of Pluto’s atmosphere reveals it is warmer, and contains more methane, than previously thought.
29 October 2008, 04:24 PM ET
Nine mementos are riding to Pluto aboard NASA's New Horizons spacecraft.
17 October 2008, 06:58 AM ET
The next three weeks will present an excellent opportunity to view Mercury.
10 October 2008, 06:28 AM ET
Neptune is much too faint to be perceived without any optical aid.
19 September 2008, 04:18 PM ET
The International Astronomical Union (IAU) announced the name of the solar system's fifth dwarf planet.