15 March 2007, 06:08 AM ET
Telescopes all over the southwest United States will turn toward Pluto as it meanders across the face of a star in the constellation Sagittarius on Sunday. The observations could help researchers better understand the diminutive world's atmosphere.
09 March 2007, 03:15 PM ET
The state of New Mexico State could effectively secede from the astronomical community if a resolution to call Pluto a planet is passed.
28 February 2007, 01:59 PM ET
We’ve been waiting for a long time and, finally, we’re on our way. But there are no “direct” flights to Pluto—the only way to get there is to first swing by Jupiter.
28 February 2007, 07:16 AM ET
Visions of a volcanic plume spewing out of Jupiter’s moon Io and a swirling storm were among the first images returned by a NASA probe as it approached an early-morning swing past the gas giant today.
18 January 2007, 04:57 PM ET
A NASA probe hurtling towards Pluto will hit the accelerator next month when it flies past the planetary giant Jupiter.
12 January 2007, 06:25 AM ET
NASA’s New Horizons probe bound for Pluto is headed for a Jupiter flyby, its camera eyes wide open, in preparation for its swing out towards the fringe of the solar system.
30 November 2006, 06:43 AM ET
BOULDER, Colorado -- Now heading outward on its lengthy trek to tiny Pluto, NASA’s New Horizons spacecraft is on course to zip by gigantic Jupiter early next year.
29 November 2006, 02:15 PM ET
A NASA spacecraft hurtling away from Earth has caught the first glimpse of its distant destination: the dwarf planet Pluto.
21 November 2006, 06:07 AM ET
The Great Pluto War in Prague failed to forge an accepted definition, but it succeeded in alienating astronomers and deepening rifts along theoretical and national lines.
15 November 2006, 05:43 PM ET
Space.com explains information about the planet Pluto.
23 October 2006, 09:43 AM ET
Pluto may be no more than a distant, icy rock in the minds of astronomers who stripped it of planethood, but its downgrade to a "dwarf planet'' has created a teachable moment in classrooms nationwide.
26 September 2006, 05:44 PM ET
NASA's New Horizons probe, bound for Pluto, snapped an image of Jupiter that astronomers said serves as a promise of what's to come early next year when the craft nears the gas giant planet.
11 September 2006, 05:38 PM ET
Pluto has been given a new name that reflects its new status as a dwarf planet.
11 September 2006, 12:55 AM ET
In an interview with SPACE.com, the new IAU president discusses the controversies surrounding the agency.
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