07 September 2006, 12:29 AM ET
A resolution in California calls the International Astronomical Union mean-spirited.
05 September 2006, 01:39 PM ET
Defenders of Pluto as a planet rallied at New Mexico State University last week, joined by the wife and son of Pluto's discoverer, Clyde Tombaugh.
01 September 2006, 05:34 PM ET
NASA's Pluto-bound New Horizons spacecraft has snapped its first high-resolution photo, an image of distant stars that shows the probe's high-resolution camera works.
31 August 2006, 02:38 PM ET
If you did not like Pluto's demotion, don't give up hope. Arguments over the newly approved definition for "planet" are likely to continue at least until 2009, and astronomers say there is much that remains to be clarified and refined.
25 August 2006, 08:12 AM ET
Text books aside, there are hundreds if not thousands of products that were or are now on the market that include Pluto as the ninth planet of the solar system.
24 August 2006, 04:41 PM ET
Not only does it leave NASA with a robotic mission en route to an "unplanet," astronomers are wondering what names will be given to all the little round objects in the outer solar system, decisions that will force changes in textbooks and curricula.
24 August 2006, 09:35 AM ET
The IAU proposed a new definition for planets would have brought the the tally to 12. It was defeated.
23 August 2006, 02:06 PM ET
A vote that could determine how Pluto is portrayed in future textbooks is set for Thursday at a meeting of the International Astronomical Union in Prague. Exactly what astronomers will be voting on is not known, however.
19 August 2006, 11:37 AM ET
Two competing proposals were put forth and no resolution reached. What's next?
18 August 2006, 10:57 AM ET
The effort to define the term "planet" took a fresh twist today as two competing proposals were put forth at a meeting of astronomers in Prague.
18 August 2006, 06:44 AM ET
New Yorkers are notoriously hard to impress, so it wasn't a surprise that many of them accepted with little fanfare the news that our solar system could soon be welcoming three new planetary members if a new proposal is accepted by astronomers.
16 August 2006, 02:00 AM ET
The tally of planets in our solar system would jump instantly to a dozen under a highly controversial new definition proposed by the International Astronomical Union (IAU).
14 August 2006, 12:54 PM ET
A new "scientific and simple" proposal to define the word "planet" will be released Wednesday and astronomers will vote on it next week. It is not clear whether the definition will settle a long-running debate on the status of Pluto, however.
21 June 2006, 05:06 PM ET
The International Astronomical Union has officially christened Pluto's two newest satellites Nix and Hydra.
08 June 2006, 12:35 PM ET
Historians and educators have joined astronomers in an effort to break a deadlock on contentious discussions. Astronomers may be allowed to vote on the proposed definition.
07 April 2006, 01:45 PM ET
NASA’s New Horizons probe has left the inner planets of the Solar System behind as it streaks toward a rendezvous with Pluto and its moons.
31 March 2006, 02:21 PM ET
NASA’s New Horizons probe hurtling towards the distant planet Pluto is in working order after a series of instrument checks, the mission’s top scientist said Thursday.
10 March 2006, 12:46 PM ET
The color of Pluto’s two recently discovered satellites are essentially the same neutral color as Pluto’s large moon, Charon. The finding supports the theory that all three of Pluto’s moons were formed from a single giant impact that took place about 4.6
28 February 2006, 06:46 AM ET
Alan Stern waited more than 17 years to see NASA launch a science mission to Pluto. He spoke about the development of the mission, his expectations and future plans via telephone and e-mail with Space News staff writer Brad Amburn.
22 February 2006, 01:03 PM ET
The two new moons discovered around Pluto last year were likely formed from the same giant impact that gave birth to the Planet’s much larger moon, Charon, scientists say.
03 February 2006, 02:04 PM ET
A spacecraft headed for the Solar System’s edge has aimed itself at the planet Jupiter in a long-distance slingshot on toward Pluto.
01 February 2006, 01:00 PM ET
The planet-sized object, catalogued as 2003 UB313, is by many accounts a planet. It is round and orbits the Sun. But because several other objects meet those criteria and also approach Pluto's size, astronomers have been wrangling over how to define the w
26 January 2006, 10:00 AM ET
NASA’s Pluto-bound New Horizons spacecraft now speeding through the Solar System is set to reach Jupiter on Feb. 28, 2007, but it will not be the first craft of its mission to reach the gas giant, mission officials said this week.
19 January 2006, 03:47 PM ET
NASA’s first probe bound for the planet Pluto and beyond rocketed toward the distant world Thursday after two days of delay due to weather.
18 January 2006, 02:49 PM ET
The planned launch of NASA’s first probe bound for Pluto has been delayed another day due to an early morning power outage at the spacecraft’s Maryland-based mission control center Wednesday.
17 January 2006, 04:28 PM ET
A NASA spacecraft destined for the planet Pluto must wait one more day after high winds prevented a Tuesday launch attempt from Florida’s Cape Canaveral Air Force Station.
17 January 2006, 06:43 AM ET
The first spacecraft ever aimed at the planet Pluto is hours away from launching into space on a nine-year mission to the distant, icy world.
15 January 2006, 05:02 PM ET
NASA’s first spacecraft aimed at the edge of our solar system is ready for its more than nine-year trek to the planet Pluto and beyond, mission managers said Sunday.
09 January 2006, 12:36 PM ET
CAPE CANAVERAL - About three dozen people assembled at the spaceport Saturday to protest this month's planned launch of a plutonium-powered space probe bound for Pluto.
06 January 2006, 03:42 PM ET
The Global Network Against Weapons & Nuclear Power in Space of Brunswick, Maine has called for a demonstration at Cape Canaveral Air Force Station in Florida on Jan. 7 to protest the launch of NASA's New Horizons Pluto mission.
04 January 2006, 01:00 PM ET
A new study provides the best estimate to date of the diameter and heft of Pluto’s moon Charon and suggests the satellite likely has no atmosphere.
03 January 2006, 06:29 AM ET
Earth-bound astronomers taking Pluto's temperature from nearly three billion miles away have confirmed suspicions that the planet is colder than it should be. It's thought that the planet’s lower temperature is the result of interactions between its icy s
30 December 2005, 06:47 AM ET
There is plenty to see, and SPACE.com provides an overview of the planets for the coming year.
23 December 2005, 08:45 AM ET
It is the first ever flight to Pluto and the first planetary flyby in decades, but for its lead scientist and one Englishwoman NASA’s New Horizon mission will mark a milestone for space exploration.
17 December 2005, 10:12 AM ET
The launch of NASA’s Pluto-bound New Horizons spacecraft is being delayed so engineers can perform precautionary boroscope inspections of the Atlas 5 rocket's first stage fuel tank.
12 December 2005, 06:41 AM ET
NASA's New Horizons spacecraft is being readied for a January liftoff to the outer reaches of the solar system. It will be humanity's first mission to Pluto and the Kuiper Belt—a vast and distant repository of the solar system's leftover building material