Huge news for those interested in astronomy: today Pluto has lost its status as a planet.

From a CNET article:

The 2006 International Astronomical Union (IAU) General Assembly voted Thursday in Prague that Pluto, formerly known as a planet, will now be considered a “dwarf planet.”

The eight planets of Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune will be grouped as “classical planets.”

Update (Aug 27, 2006): Here’s some additional news that I’ve found across the net concerning Pluto’s demotion to dwarf planet:

From the CNET article “Textbook publishers grapple with Pluto demotion”:

Such fundamental changes to what kids are taught don’t happen very often. It’s like dropping Australia off the list of continents. Wikipedia got the change right away. So did other Internet resources. Now try correcting the millions of science textbooks, standardized tests, films and even solar system models that will be used in a classroom this fall.

From the ABC article “Pluto becomes one less planet to memorize”:

Pluto’s lost status disappointed some schoolchildren and had space museum curators scrambling but in the words of one teenager, “It’s one less planet to memorize.”

From the CNET article “Pluto: And then there were eight”:

Three other bodies had been contending for planetary status as well: Ceres, the largest-known asteroid; “Xena,” the nickname for 2003 UB313; and Charon, which has been considered Pluto’s moon.

Ceres and “Xena” will now share “dwarf planet” status with Pluto. Charon, it has been concluded, will be grouped with “small solar-system bodies.”

From an Los Angeles Times article titled “Pluto Learns Eight Is Enough for Planets”:

Members of the International Astronomical Union overwhelmingly voted to demote Pluto to a “dwarf planet.” Though still retaining the term planet, it was clear that Pluto had been exiled.

“Pluto’s out,” said Michael E. Brown, the Caltech astronomer whose discovery last year of a planet-like object called UB313 reignited the long-running debate over whether Pluto should be considered a planet. “People are going to be unhappy, but it’s the right thing to do. This is a great moment in science.”


“Poor little Pluto,” said Patricia Tombaugh, the 93-year-old widow of the man who discovered Pluto, Clyde Tombaugh. “Kids are going to be upset.”

From an Associated Press article on Yahoo News titled “Widow of Pluto’s discoverer ‘shook up'”:

The widow of the astronomer who discovered Pluto 76 years ago said Thursday she was frustrated by the decision to strip it of its planetary status, but she added that Clyde Tombaugh would have understood.

“I’m not heartbroken. I’m just shook up,” Patricia Tombaugh, 93, said in a telephone interview from her home in Las Cruces.


Tombaugh had fought off other attempts to relegate Pluto, but his widow said this time he probably would have endorsed the change, now that other planetary objects have been discovered in the Kuiper Belt, the belt of comets on the edge of the solar system where Pluto resides.


[Jim Murphy of the New Mexico State University] said the declaration won’t change Pluto’s importance to science.

“Pluto didn’t cease to exist,” Murphy said. “It didn’t lose or gain any atoms. Its physical characteristics haven’t changed a bit because of this.”