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[Chicago Astronomer - Astro Joe]

9th rock from sun, Pluto, under cosmic debate: Is it planet?

WASHINGTON -- Ask most schoolchildren how many planets there are in our solar system, and they'll tell you nine.

It has been that way since 1930, when a Kansas farm boy with a passion for astronomy detected Pluto, the ninth planet.

But soon, there could be only eight. Pluto faces demotion.

At a conference in Prague, Czech Republic, this month, the International Astronomical Union, which oversees such matters, is scheduled to consider a resolution that defines a planet.

Driven largely by controversy over the status of Pluto, which doesn't share several key attributes of the eight other planets, the resolution could mean Pluto's dismissal from that group.

Instead, it could be defined as simply one of thousands of small, icy objects in the less glamorous Kuiper Belt, just beyond Neptune.

An alternative would be to maintain Pluto's planetary credentials, but that potentially opens the door to dozens more planets.

"This is such a hot issue," said Stephen Maran, author of "Astronomy for Dummies."

The committee writing the resolution has worked in secret. Few people know what it will recommend. Those who know aren't talking. Egos are involved. Some say U.S. pride has emerged; Pluto is the only one of the nine discovered by an American. And there's no guarantee that the conference will accept the recommended resolution, whatever it is.

From a purely scientific perspective, downgrading Pluto is no big deal, said Daniel Green of the Smithsonian Astrophysical Observatory.

"All through history, we have changed the number of planets," Green said. "There used to be only seven planets. People thought the sun and the moon were planets and the Earth wasn't. Things change."

Virtually since its discovery, questions dogged Pluto. It wasn't like the other planets. Too small. Erratic orbit. Not enough of a rocky center.

Many scholars questioned Pluto's inclusion as a planet.

In 2000, the Hayden Planetarium at the American Museum of Natural History in New York City opened a solar system exhibit. Conspicuously missing as a planet was Pluto. The argument that had long engulfed scientific circles exploded into public view.

"My files are overfilled with hate mail from elementary students," said Neil deGrasse Tyson, the planetarium's director, who called Pluto "a vagabond of the solar system."

The arguments for keeping Pluto as a planet: It's a large, round object that orbits the sun. It has an atmosphere. It has moons.

"It just fits into the bag of being a planet better," said Mark Sykes, director of the Planetary Science Institute in Arizona. "We know enough to know it's not just an inert ball of ice."

Source: www.chicagotribune.com/news/nationworld/chi-0608130332aug13,1,4804765.story?coll=chi-newsnationworld-hed

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I say, if Mercury is a planet, so stays Pluto.

[Maddad]

They're adding a third class of planets. After Terrestrial and Jovians, they'll have Plutons.

[Chicago Astronomer - Astro Joe]

Is Pluto a Planet? Astronomers Vote, JHU Takes Straw Poll

Baltimore MD (SPX) Aug 21, 2006
Generations of schoolchildren have memorized "My Very Energetic Mother Just Served Us Nine Pizzas" (or a variation thereof) in order to remember the order of the nine planets in our solar system. For 70 years - ever since it was discovered - the "p" in that oft-repeated mnemonic device has stood for Pluto, the ninth and smallest planet.

But is Pluto actually a planet? Or is it something else? Astronomers have been debating this issue - often, hotly -- since Pluto's discovery seven decades ago.

An informal poll of astronomers at the Henry A. Rowland Department of Physics and Astronomy at the Johns Hopkins University's Krieger School of Arts and Sciences and the Johns Hopkins University's Applied Physics Laboratory reveals that though _most_ favor Pluto's continued existence as a planet and establishing a new definition of the word, the notion of a "pluton" is less well-received. Here is a sampling:

• But if I were in charge, I would insist on a diameter of greater than 1,000 kilometers to define a 'planet' in order to remove Ceres from the list.
  
• Allowing Charon to itself be called a planet, with Pluto and Charon being a 'double planet' system. This goes too far and seems inconsistent to me."
  
• 'Down with Pluto' is what I say!"
  
• "Yes, keeping Pluto as a planet is the correct decision.
  

Read the entire poll results here:
www.spacedaily.com/reports/Is_Pluto_a_Planet_Astronomers_Vote_JHU_Takes_Straw_Poll_999.html

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I say yes on Pluto, yes on Ceres, yes on Xena...but a resounding NO for Charon.

[Chicago Astronomer - Astro Joe]

Pluto an Underdog Once Again

Aug. 27--Before astronomers gave it the bum's rush last week, Pluto was the first American planet.

It was the first planet discovered here, spotted in 1930 by Clyde Tombaugh, who was born and raised on the farms of Illinois and Kansas.

Pluto also was the first democratically named planet; the name that stuck was suggested not by a professional astronomer but by an 11-year-old English schoolgirl named Venetia Burney.

Puny it may be. But Pluto stood out. It was the people's planet.

That's one reason it rankles that a few hundred astronomers in Prague, Czech Republic, have up and voted Pluto off the local cosmic island.

Forget all the science books you read as a kid, or even what most planetariums told you before Thursday. Only trained members of the International Astronomical Union get to set rules for the heavens, and they know better than you.

Well, nuts to that.

What the crowd in Prague forgot is that Pluto doesn't belong to them. It belongs just as much to the 4-year-old kid in Chicago who showed up at the Adler Planetarium last week with the woebegone planet's name taped to his shirt, scrawled on a piece of paper.

Surveys suggest that more than 60 percent of people want to keep Pluto a planet. It's part of our culture, our common language. Since when does a PhD in astronomy get a veto over that?

My job as a science writer often calls for patient reflection, and the careful weighing of intricate theories that only a few researchers truly understand. Sometimes unpleasant scientific facts trump popular sentiment.

This is not one of those times. This is a time to go to the mat for the little guy. The decision to banish Pluto is as subjective as the general public's inclination to keep it around.

Although astronomers have known for decades that Pluto is smaller than Earth's moon, only now is that knowledge presented as proof positive the tyke can't be a planet. Supporters of the Pluto demotion seem to think that if they keep stressing its dinky size, the planet's silly boosters will realize their error.

Problem is, we know it's small. We like that it's small.

Granted, it's frustrating for some astronomers. Every day, scientists engage in smackdown fights over how to classify some new space rock or rain-forest bug, and the wider world takes no notice. Shouldn't scientists be able to settle on a new definition of what counts as a planet without taking flak from the hoi polloi?

Sorry, but no.

Maybe it was different in the 1800s, when for a few decades astronomers listed newly discovered Ceres as a planet, before realizing that it was really just the largest asteroid among thousands. Astronomers quietly demoted tiny Ceres, and no one seemed to care.

But Pluto is a creature of the 20th Century, when radio and TV spread the world's romance with space travel. People got to like that little planet.

More here: www.redorbit.com/news/space/633530/pluto_an_underdog_once_again/index.html?source=r_space

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Sentiments aside, (which often cloud logical judgements), Pluto should remain a planet because it meets many of the critieria set for planet status.