18 June 2008, 10:21 AM ET
Its existence would satisfy the long-held hopes and hypothesis for a "Planet X" envisioned by scientists and sci-fi buffs alike.
12 June 2008, 03:38 PM ET
Disgruntled scientists renewed their vows this week to call Pluto a planet despite an international governing body's latest ruling to reclassify the tiny world.
11 June 2008, 02:36 PM ET
The Pluto-bound New Horizons spacecraft crossed the orbit of Saturn on June 8.
11 June 2008, 10:30 AM ET
The IAU decides on a name for Pluto and other round objects way out there.
29 November 2007, 06:39 AM ET
Thoughtful astronomy books abound for the holiday gift-giving season.
26 November 2007, 06:44 AM ET
Colossal impacts may have bowled over remote, frozen moons
12 October 2007, 01:48 PM ET
New images bring Pluto and its moons into sharper view.
09 October 2007, 10:38 AM ET
Brief fly-by of New Horizons spacecraft captures an unusually calm Jupiter.
01 October 2007, 06:35 AM ET
Puffy debris disk around three nearby stars could harbor Pluto-sized planets-to-be.
17 July 2007, 04:20 PM ET
Slushy geysers on Plutoâ€™s moon Charon coat the tiny world in ice crystals and make it the outer solar system equivalent of an ice machine.
14 June 2007, 02:00 PM ET
The dwarf planet that forced astronomers to strip Pluto of its planethood is not only bigger than the former ninth planet, but also much more massive, a new study finds.
01 May 2007, 02:01 PM ET
NASA is presenting a series of stunning new images today of the Jupiter system snapped by its probe New Horizons earlier this year.
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.