WKSU News: No apologies for Pluto's demotion

Tuesday, March 03, 2009 No apologies for Pluto's demotion Astronomer tells Kent State Stark audience Pluto is just part of a swarm by WKSU's TIM RUDELL	Reporter Tim Rudell

Mike Brown says he still gets hate e-mails from school kids and NASA scientists over the determination that Pluto is a dwarf planet, not a full planet.

Michael Brown helped demote Pluto " and says the pseudo planet deserved it. The astronomer defended the downgrade at Kent State's Stark campus last night (Tuesday).

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The solar system has gone from nine planets to eight in large part because of Mike Brown's discovery of a dwarf planet.

The number of dwarf planets now numbers five, including Pluto

With Pluto in the mix, Mike Brown's drawing shows a tidy version of the universe

Four new dwarf planets, and the demotion of Pluto to a dwarf plant, changes a tidy solar system

Before the demotion: On February 18, 1930, American astronomer Clyde Tombaugh came across a new planet after months of combing the sky in search of an elusive, undiscovered celestial body. The new planet, Pluto, was about 30 times less massive than Mercury, the smallest known planet. It also was characterized by its unique orbit pattern, which crossed with the path of Neptune. What makes a planet a planet? On August 24, 2006, just 76 years after the small, frozen planet's discovery, the International Astronomical Union's General Assembly in Prague adopted its official definition of the word "planet," which took Pluto out of the starting rotation and sent it back to the minors " a group of celestial bodies known as dwarf planets. Dwarf planets are any object in space, other than the eight planets, that meet certain size and roundness requirements because of gravitational attraction. Gravitational attraction affects an object's shape over time. If a small rock mass is placed in space, it will retain its irregular shape. Add enough rock to the pile and it will slowly begin to pull itself in until it becomes round. The shape is important to a planet's possible classification because it partly discloses how much gravitational attraction it has. Its mass and gravitational pull must also clear the neighborhood of larger bodies around its orbit. Current dwarf planets: At first, the International Astronomical Union listed three bodies that fit its criteria for dwarf planets: the former planet Pluto, Ceres, the largest and only known round asteroid, and Eris, which is believed to be somewhat larger than Pluto. Dwarf planets Makemake and Haumea were later observed and added to the list. Some astronomers speculate that while these five are the only official sanctioned dwarf planets, more could exist in the Kuiper belt, an asteroid belt-like region that extends outward from Neptune's orbit.

More on Eris

Mike Brown talks about drawf planets and other universe wonders

Listener Comments:

Pluto doesn't clear its neighborhood though. It also doesn't have enough mass that it's a majority of the kuiper belt

so I have to disagree with you,Laurel

Pluto is one of many kuiper belt objects

Posted by: Raymond Andrews (Sacramento,California) on August 12, 2009 10:47PM

It's true, Michael Brown had genuinely wanted his own discovery of bodies farther away than Pluto to be added to the list of planets, particularly his inappropriately named "Xena"; when his claim was rejected, then he decided to pursue the claim that Pluto shouldn't be a planet either.

It's all a matter of man's childish insecurities being realised.

Posted by: MEKR (T) on March 7, 2009 12:56PM

Pluto is NOT a "pseudo-planet," and while Brown does not need to apologize for his opinions, neither can he force those opinions down the throats of other scientists or the world at large. Pluto is NOT just one of a swarm of objects. Saying this ignores the crucial factor that separates Pluto from those neighbors, namely that Pluto, like the larger planets, is spherical due to being in a state of hydrostatic equilibrium. This means it is large enough to be pulled into a round shape by its own gravity rather than to be shaped by chemical bonds, as the other objects in the neighboring "swarm" are. The fact that NASA scientists--and many planetary scientists worldwide--continue to reject the demotion of Pluto and the nonsense that dwarf planets are not planets at all should be a red flag right there, making it obvious that this is not a done deal, that the debate is still very much ongoing, even if Brown wishes it were not. As many scientists and lay people are working to overturn the demotion or are ignoring it altogether, there is a good chance it will not stand in the long run.

And it is interesting to note that Brown himself was for Pluto and Eris being considered planets before he was against it. Makes one wonder...

Posted by: Laurel Kornfeld (Highland Park, NJ) on March 4, 2009 3:22PM

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