If a Planet is dropped, will anyone notice?

By taking Pluto off the planetary map, Neil Degrasse Tyson has put himself on the astronomer map. But it took a while.

Do you remember the mnemonic about the planets? My Very Educated Mother Just Served Us Nine Pizzas. Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto. Guess what, Mom turned out to be empty-handed.

Back around the year 2000, Tyson–director of Hayden Planetarium, part of the American Museum of Natural History–looked at the data and dropped Pluto from their new planetary exhibit. In effect, an obit from the planetary orbit. How could he not? At Caltech, someone had even discovered an iceball bigger than Pluto! Today Pluto is considered part of the icy worlds beyond Neptune.

Tyson–even though Mike Tyson has been referred to as ‘being from another planet‘, there is no relation–got a lot of negative feedback, not unlike this one from an elementary school child:

I think Pluto is a planet. Why do you think Pluto is no longer a planet? I do not like your answer!!! Pluto is my faveret planet!!! You are going to have to take all of the books away and change them. Pluto IS a planet!!!!!!!

Tyson’s problem was that the industry’s ruling society, the International Astronomical Union, would not get around to ruling on Pluto for a few more years. Actually, Tyson’s real problem was that no one noticed until an article by Kenneth Chang in 2001. Chang followed up recently to vindicate Tyson. Tyson has a new book about it all, The Pluto Files.

All articles referenced are copied in full at end of post.

How I (Ken Chang) Tormented Neil Degrasse Tyson
January 8, 2009, 4:02 pm

By Kenneth Chang

Neil deGrasse Tyson is director of the Hayden Planetarium at the American Museum of Natural History here in Manhattan. This month, he has a new book coming out called “The Pluto Files.”

It’s all my doing, hee hee.

It’s a cool ego stroke to find an index entry for oneself at the back of a book: “Chang, Kenneth, 80-83, 85-87.” Turning to those pages, I found Dr. Tyson telling how a Kenneth Chang article “would disrupt my life for years to come.” He gets bonus points for describing me as “eager, smart, young.”

It’s also notable how rare something that I write in The New York Times generates identifiable ripples in the world.

A bit of backstory: When the museum’s Rose Center for Earth and Space opened in February 2000, it quietly left out planethood for Pluto, placing it instead among the “icy worlds” beyond Neptune. This was years before the International Astronomical Union officially reclassified Pluto as a dwarf planet. Yet almost no one noticed the museum’s actions. Actually, the New York Post noticed in its preview of the new center, and no one noticed that.

Months passed. Then someone in the sports department noticed and told Cory Dean, then the science editor. She called me over and said, “I don’t know if there’s anything to this, but check it out.” I called the museum, which yielded a quizzical response that they hadn’t done anything since the Rose Center opened months earlier. I interviewed Dr. Tyson and other astronomers. I tromped up to the museum a couple of times to look at the incriminating exhibits and talk to confused visitors.

The result was this article, published Jan. 22, 2001, two days after George W. Bush was inaugurated: “Pluto’s Not a Planet? Only in New York.”

I knew I had written a good article. I thought it was one of those “fun reads” that people would enjoy, share with friends, and forget in a week.

Man was I wrong. I turned Dr. Tyson into Public Enemy Astronomer #1, for years.

Take this letter he received from an elementary school child:

I think Pluto is a planet. Why do you think Pluto is no longer a planet? I do not like your answer!!! Pluto is my faveret planet!!! You are going to have to take all of the books away and change them. Pluto IS a planet!!!!!!!

And then there was the response he got from other scientists like Robert L. Staehle of NASA’s Jet Propulsion Laboratory:

What gives? Did someone there have a memory lapse? What will take to get Pluto back up there where it belongs?

The museum quickly added a plaque explaining, “Where’s Pluto?” I consider that my personal plaque. Until Dr. Tyson’s book, this was the one thing I could point to and say, “I caused that.”

But I didn’t cause any of the larger events, and there was little that I, or any other newspaper reporter, could have written to alter them much. Certainly, the media could not have saved Pluto’s planetary status. Pluto would have become a dwarf planet regardless, because Michael Brown of Caltech discovered an iceball bigger than Pluto. (Not that I was trying to change anything. I didn’t consider myself a persecutor or defender of Pluto. I just thought it was a fun story.)

Now, a year and a half after the International Astronomical Union decision, it seems to me that most people have reached the acceptance stage that there are eight planets in the solar system. And for all the grief Dr. Tyson suffered, at least he will get royalties.
Pluto’s Not a Planet? Only in New York

January 22, 2001


As she walked past a display of photos of planets at the Rose Center for Earth and Space, Pamela Curtice of Atlanta scrunched her brow, perplexed. There didn’t seem to be enough planets.

She started counting on her fingers, trying to remember the mnemonic her son had learned in school years ago.

My Very Educated Mother Just Served Us Nine Pizzas.

Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune.

”I had to go through the whole thing to figure out which one was missing,” she said.


Pluto was not there.

”Now I know my mother just served us nine,” Mrs. Curtice said. ”Nine nothings.”

Quietly, and apparently uniquely among major scientific institutions, the American Museum of Natural History cast Pluto out of the pantheon of planets when it opened the Rose Center last February. Nowhere does the center describe Pluto as a planet, but nowhere do its exhibits declare ”Pluto is not a planet,” either.

”We’re not that confrontational about it,” said Dr. Neil de Grasse Tyson, director of the museum’s Hayden Planetarium. ”You actually have to pay attention to make note of this.”

Still, the move is surprising, because the museum appears to have unilaterally demoted Pluto, reassigning it as one of more than 300 icy bodies orbiting beyond Neptune, in a region called the Kuiper Belt (pronounced KY-per).

”Pluto is noticeable by its difficulty to find,” Dr. Richard P. Binzel, a professor of planetary science at the Massachusetts Institute of Technology, said of the Rose exhibits. ”They went too far in demoting Pluto, way beyond what the mainstream astronomers think.”

Dr. S. Alan Stern, director of Southwest Research Institute’s space studies department in Boulder, Colo., also dislikes the change. ”They are a minority viewpoint,” he said. ”It’s absurd. The astronomical community has settled this issue. There is no issue.”

The International Astronomical Union, the pre-eminent society of astronomers, still calls Pluto a planet, one of nine of the solar system. Even a proposal in 1999 to list Pluto as both a planet and a member of the Kuiper Belt drew fierce protest from people who felt that the additional ”minor planet” designation would diminish Pluto’s stature.

The proposal was abandoned, and the astronomical union, which is based in Paris, released a statement reaffirming that Pluto was and is a planet. ”This process was explicitly designed to not change Pluto’s status as a planet,” the organization said.

But even some astronomers defending Pluto admit that were it discovered today, it might not be awarded planethood, because it is so small — only about 1,400 miles wide — and so different from the other planets.

While the international union’s debate stirred considerable astronomical passion, the Rose Center’s Plutoless planet display has not generated much controversy or consternation.

”I learned it one way for the first 50 years,” said Mrs. Curtice’s husband, William. ”I’ll learn it another way now, I guess.”

Jane Levenson, an ”explainer” at the center, says that perhaps one out of every 10 visitors asks her about the missing planet. She tells them about the debate over Pluto’s status and says ”a decision had to be made” as the museum was assembling the new exhibits.

”Children in particular ask,” she said. ”Children say, ‘Did they forget about Pluto?’ Some even say, ‘Did you forget my friend Pluto?’ ”

Ilisse Familia, a sixth grader from the Good Shepherd School in Manhattan, was surprised when she heard the museum no longer counted Pluto among the planets. ”No wonder I couldn’t find Pluto,” she said. ”It’s kind of weird.”

As a planet, Pluto has always been an oddball. Its composition is like a comet’s. Its elliptical orbit is tilted 17 degrees from the orbits of the other planets. Pluto was discovered on Feb. 18, 1930, by Clyde W. Tombaugh, and astronomers initially estimated it to be as large as Earth. They have since learned it is much smaller, smaller than Earth’s Moon.

But Pluto continued to be called a planet, because there was nothing else to call it. Then, in 1992, astronomers found the first Kuiper Belt object. Now they have found hundreds of additional chunks of rock and ice beyond Neptune, including about 70 that share orbits similar to Pluto’s, the so-called Plutinos.

”We’re much more subtle, but not deviously subtle,” Dr. Tyson, the planetarium director, said of the Hayden exhibits. ”We decided to organize the information for the visitor in such a way that Pluto’s classification would become self-evident.”

The exhibits refer to the inner four ”terrestrial planets” — Mercury, Venus, Earth, Mars — and the four gas giant planets — Jupiter, Saturn, Uranus and Neptune. Pluto, a small ball of rock and ice, does not fall into either group. ”Pluto does not have a family except for the icy bodies in the outer solar system,” Dr. Tyson said. ”So we simply group it with the Kuiper Belt. In a sense, we’re sidestepping the definitional problem altogether.”

A display describing the solar system includes this carefully worded sentence: ”Beyond the outer planets is the Kuiper Belt of comets, a disk of small, icy worlds including Pluto.”

A diagram of the planets shows eight, not nine, rings around the Sun.

Other planetariums have not followed the Rose Center’s lead. The entryway to the Adler Planetarium in Chicago includes bronze plaques of only eight planets, but that is because it opened just before Pluto was officially named. Inside, the exhibits include Pluto among the planets.

The Denver Museum of Nature and Science is building a $45 million, 30,000-square-foot space science center, scheduled to open in 2003. Those exhibits will also still count nine planets in the solar system. ”We’re sticking with Pluto,” said Dr. Laura Danly, curator of space sciences at the Denver museum. ”We like Pluto as a planet.”

But, she also said, ”I think there is no right or wrong on this issue. It’s a moving target right now, no pun intended, what is and is not a planet.”

Planet, in the original Greek word, meant ”wanderer,” referring to the dots of light that moved across the night sky. When the 16th-century astronomer Nicolaus Copernicus realized that the universe did not revolve around the Earth, Earth became another planet circling the Sun.

For Dr. Tyson, the redefining of Pluto has historical precedent. In 1801, astronomers combing the large gap between Mars and Jupiter discovered Ceres, and for a short while, Ceres was a planet. Then another large rock was found in the same region. And another. Soon it became apparent there was a ring of rocky bodies between Mars and Jupiter. Since astronomers did not want to call all of them planets, they renamed them asteroids.

Just as Ceres, which turned out to be about 580 miles wide, was reassigned from planet to asteroid, Pluto should join the Kuiper Belt objects, Dr. Tyson said. ”It’s entirely analogous to the asteroid belt,” he said, ”except there’s a 60-year delay between the discovery of the first and second objects.”

The new view of Pluto would recast it ”from puniest planet to king of the Kuiper Belt,” Dr. Tyson said. ”And I think it’s happier that way. I’m convinced our approach will prevail. It makes too much scientific sense and too much pedagogical sense.”

About Jorge Costales

- Cuban Exile [veni] - Raised in Miami [vidi] - American Citizen [vici]
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1 Response to If a Planet is dropped, will anyone notice?

  1. Pluto IS a planet because unlike most objects in the Kuiper Belt, it has attained hydrostatic equilibrium, meaning it has enough self-gravity to have pulled itself into a round shape. When an object is large enough for this to happen, it becomes differentiated with core, mantle, and crust, just like Earth and the larger planets, and develops the same geological processes as the larger planets, processes that inert asteroids and most KBOs do not have.Not distinguishing between shapeless asteroids and objects whose composition clearly makes them planets is a disservice and is sloppy science. As of now, there are three other KBOs that meet this criterion and therefore should be classified as planets—Haumea, Makemake, and Eris. Only one KBO has been found to be larger than Pluto, and that is Eris.The IAU definition makes no linguistic sense, as it states that dwarf planets are not planets at all. That’s like saying a grizzly bear is not a bear. Second, it defines objects solely by where they are while ignoring what they are. If Earth were placed in Pluto’s orbit, by the IAU definition, it would not be a planet. That is because the further away an object is from its parent star, the more difficulty it will have in clearing its orbit.Significantly, this definition was adopted by only four percent of the IAU, most of whom are not planetary scientists. No absentee voting was allowed. It was done so in a highly controversial process that violated the IAU’s own bylaws, and it was immediately opposed by a petition of 300 professional astronomers saying they will not use the new definition, which they described accurately as “sloppy.” Also significant is the fact that many planetary scientists are not IAU members and therefore had no say in this matter at all.Many believe we should keep the term planet broad to encompass any non-self-luminous spheroidal object orbiting a star. We can distinguish different types of planets with subcategories such as terrestrial planets, gas giants, ice giants, dwarf planets, super Earths, hot Jupiters, etc.We should be broadening, not narrowing our concept of planet as more objects are being discovered in this and other solar systems.In a 2000 paper, Dr. Alan Stern and Dr. Hal Levison distinguish two types of planets—the gravitationally dominant ones and the smaller ones that are not gravitationally dominant. However, they never say that objects in the latter category are not planets.I attended the Great Planet Debate, which actually took place in August 2008, and there was a strong consensus there that a broader, more encompassing planet definition is needed. I encourage anyone interested to listen to and view the conference proceedings at http://gpd.jhuapl.edu/ You can also read more about this issue on my blog at http://laurele.livejournal.comYou can find the petition of astronomers who rejected the demotion of Pluto here: http://www.ipetitions.com/petition/planetprotest/

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