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Pluto's status in IAU Rio meeting?

The subject may never come up.

"Pluto's planetary plea not in scientists' scope"

Formerly known as a planet, heavenly body's demotion is likely to stick at new meeting

by

Eric Berger

August 2nd, 2009

Houston Chronicle

When they convene Monday in Rio de Janeiro, the grand pooh-bahs of astronomy appear unlikely to revisit their decision from three years ago to demote Pluto, the heavenly body formerly known as the solar system's ninth planet.

The ostracism of Pluto comes despite a slow boil among many U.S. astronomers seething ever since the International Astronomical Union's declassification, as it was the only planet ever found by an American astronomer, Clyde Tombaugh.

"My guess is that the officers of the IAU are going to do their level best to keep Pluto's head from rising at this meeting," said astronomer Stephen Maran , co-author of a new book called Pluto Confidential.

"I think they were very embarrassed about what happened at the last general assembly."

When the IAU general assembly last met three years ago, the world watched as a majority of just 424 total votes were cast to put Pluto in what astronomers felt was its rightful place.

Not only did the scientists at the Prague-based meeting vote to classify Pluto as a "dwarf planet," Maran said, but with perhaps a tinge of anti-Americanism amid the Iraq War they also took the punitive step of ruling that dwarf planets themselves were not planets.

Within weeks of its demotion, Pluto was given the numerical designation 134340 by the IAU's Minor Planet Center, which largely catalogs asteroids. Pluto was now just a number.

The swift and unexpected demotion of Pluto startled the American public, which protested through state legislature resolutions, petitions signed by astronomers to restore Pluto to planethood, and even a song by the band SubPlot A dubbed Pluto Rocks.

Despite all of this, with the first opportunity to finally change Pluto's official status, it's nowhere to be found on the IAU agenda.

"No resolution was submitted in the past months, so it is unlikely that the Pluto issue, or any other solar system naming matters, will come before the General Assembly," said Robert Williams , a Baltimore-based astronomer who is the IAU's president-elect.

So with no revision to Pluto's status is the former planet's demotion officially a fait accompli?

Not likely, said Mark Sykes, director of the Planetary Science Institute in Tuscon, Ariz.

"The IAU executive committee does not want to address it," Sykes said. "They put out their encyclical, and they're basically done with it. But does the IAU dictate thought? No, they're not the holy mother church. There are a lot of scientists who will simply ignore what they have done and continue to refer to and write about Pluto as a planet."

Celestial evidence

Sykes said he believes evidence will come out within the next decade that will force the IAU to reverse its decision on Pluto.

Two separate probes, the Dawn mission to the large asteroid Ceres and the New Horizons probe to Pluto, should reach their respective targets in the year 2015.

The IAU definition essentially treats dwarf planets such as Ceres and Pluto as innate hunks of rock, Sykes said. But both of these bodies have atmospheres, and Sykes believes the probes will also find evidence of geological activity. Ceres might even have a sub-surface ocean.

"I think we're going to find that these planets are much more like the Earth than Earth is like Jupiter," he said.

Not all American astronomers agree. Foremost among Pluto's detractors is Neil deGrasse Tyson , who as director of the Hayden Planetarium at the American Museum of Natural History in New York City in 2000 omitted Pluto from an exhibit of the planets.

At the Houston Museum of Natural Science, Pluto remains entrenched in an outdoor diagram of the planets, with a plaque that still lists it as a planet.

"We have no plans to remove the object since it's still there in the real solar system," said Carolyn Sumners , the museum's director of astronomy. "Since changing plaques is expensive and Pluto's status is still in flux, we decided to leave the plaque as it is and see if the astronomical community can reach a more permanent consensus."

Type Pluto in the search engine for more material.

February skys yield five naked eye planets

What a treat...five planets that will be visible to the naked eye.

"Doorstep Astronomy: Spot 5 Planets"

by

Joe Rao

February 13th, 2009

SPACE.com

This month you'll have an opportunity to see all five naked-eye planets – but not all at once. Two of them are evening objects, while the other three are clustered together low in the east-southeast sky deep in the dawn twilight.

The planets move around in our sky and become brighter and dimmer over time depending on where they are in their orbits around the sun. Uranus, Neptune and Pluto are never visible to the naked eye.

Here's what you can look for:

The Evening Lantern

If you ever wanted to see a planet so bright it will take your breath away, this is your week and Venus is the planet. It hangs lantern-like, high in the west as darkness falls. It's so bright now that you should have little trouble finding it even before sunset in a clean, deep blue sky – which is also a good time to look at its dramatic crescent shape in a telescope.

As dusk starts to fade, this unrivaled heavenly lamp can scarcely be missed â€" you won't need a map. Venus sets more than 3 hours after the sun.

Venus is now at the pinnacle of brilliancy for this current evening apparition. Viewed through a telescope in the coming weeks, its crescent grows larger but thinner as the planet approaches the Earth in the celestial scheme of things and shows us more of its night side. By month's end Venus is similar in apparent size to Jupiter – but less than one-quarter of it is lit.

Gray markings in the planet's cloud cover remain quite subtle. Look around sunset, when the sky is brighter and Venus's crescent is less dazzling than it becomes after dark. Also, watch for signs of the mysterious ashen light – a still unexplained illumination that some observers have occasionally noticed in parts of Venus's night side.

On the evening of Feb. 27 the Americas will be greeted with one of the most spectacular Venus-crescent moon conjunctions possible. The pairing will persist from before sunset into the depths of darkness. Venus will sit about 1.5-degrees above and to the right of the three-day old crescent. Be sure not to miss this!

Lord of the Rings

The next planet to look for is Saturn. This week it comes up above the eastern horizon about 90 minutes after sunset, but by the time of its opposition to the sun on March 8 it will be visible all night from dusk to dawn. Two nights later, on March 10, Saturn will ride high above the full moon.

Brightening slightly from magnitude +0.7 to +0.5, Saturn appears twice as bright as the bluish star, Regulus, the brightest star of Leo, the Lion. Shining sedately with a yellow-white hue, Saturn appears far to the lower left of that first magnitude star during the evening.

If you have a telescope magnifying at least 30-power, you'll be able to glimpse the famous ring system, which now looks like a bright line that bisects Saturn's disk. The rings open slightly to 2.3-degrees from edgewise by the end of February, but the rings will start closing again later this spring, ultimately disappearing even in big telescopes by midsummer.

A planetary trio

The other three planets visible are morning objects. Two of these are visible toward month's end but with some difficulty: Jupiter and Mercury.

Solar conjunction for Jupiter was on Jan. 24; by the final week of February it'll be on its way back into view, appearing a little higher each day. Off to its upper right will be fainter Mercury. Bring binoculars for this challenging sighting; the two planets will be very low above the east-southeastern horizon about 30-35 minutes before sunrise.

Just before sunrise on the 22nd, seek out the slender sliver of an old crescent moon, just 2-½ days before new phase, low near the east-southeast horizon. If you find it, use it as your guide to locate Mercury and Jupiter, located about 5 or 6-degrees to the moon's lower left. Binoculars will help.

Jupiter and Mercury engage in a close conjunction early on the morning of Feb. 24, with Jupiter appearing to stand almost directly above Mercury; they're separated by 0.7-degree. For comparison, the moon's apparent width is 0.5-degree. The place to look is very low in the east-southeast. Mercury shines at a respectable magnitude -0.1, but still appears only about one-sixth as bright as Jupiter's -2.0.

The only planet seemingly out of the loop in terms of visibility is Mars. Shining at magnitude +1.3 and rising deep in the glow of dawn less than an hour before sunup, it's not yet a naked-eye object for mid-northerners. Nonetheless, on the mornings of Feb. 16, 17 and 18, Mars and Jupiter will be separated by less than 1-degree. On the 17th, in fact, Jupiter will appear just 0.6-degree to the upper left of Mars. So if you can locate Jupiter, you should be able to find Mars with binoculars or a small telescope.

And with Mercury close by this makes for a planetary trio. For those Space.com readers living south of the equator, these three planets will appear a bit higher and against a somewhat darker sky; hence making them easier to see.

Tyson, Weintraub, Tombaugh & Pluto

Clyde Tombaugh

Alan Boyle, MSNBC's science reporter, discusses Neil deGrasse Tyson's book The Pluto Files and David Weintraub's book Is Pluto a Planet? There is also an interview with Clyde Tombaugh [including video clips].

MSNBC


Tyson's interview with "Time" on Pluto and planets

Pluto="Plutoid"

Pluto

Does this satisfy everyone now?

""Plutoids": the new name for Pluto-like dwarf planets"

by

Jon Cartwright

June 12th, 2008

physicsworld.com

Pluto sub-classification

The International Astronomical Union (IAU) has decided that Pluto — and other dwarf planets in the Solar System that share similar characteristics — should now be sub-classified as "plutoids".

The revised classification comes almost two years after Pluto was demoted from "planet" to "dwarf planet" in order to dispel inconsistencies in Solar System nomenclature that have arisen as more orbiting bodies have been discovered.

A dwarf planet is a body orbiting the Sun that has enough gravity to assume a near-spherical shape, but that is not the sole occupant of its orbit. To be a "plutoid", according to the IAU, the dwarf planet must also be orbiting at a greater distance than Neptune. Aside from Pluto, the only other known dwarf planet fitting this specification is Eris, although more are expected to be found in the future.

The IAU, which has been responsible for the classifying planetary bodies and satellites since the early 1900s, had always planned to create sub-classes within the class of "dwarf planet". The name "plutoid" was proposed by the IAU Committee on Small Body Nomenclature, and then accepted by the IAU Working Group for Planetary System Nomenclature and the board of IAU’s Division III, which concerns planetary systems. It was finally approved by IAU executives at a recent meeting in Oslo, Norway.

Still criticized

When Pluto was first reclassified, some astronomers criticized the definition for not being robust enough, in particular because the orbits of certain planets — including Earth — also overlapped with other bodies. On top of that, they complained that there were not enough astronomers consulted when decision was made.

Catherine Cesarsky, president of the IAU, dismisses such past protests. "They form a very small part of the astronomy community," she told physicsworld.com. She added that "practically nobody" is now trying to get Pluto reclassified as a planet.

However, Alan Stern, principal investigator for NASA’s New Horizons mission to Pluto, has already mocked the new plutoid definition. "Plutoids or haemorrhoids, whatever they call it. This is irrelevant," he has been reported as saying.

Cesarsky admits that she has not yet heard the response from the astronomy committee for the rebranding. "I don’t think there will be a big [reaction]," she says. "A few people make a lot of noise."


What's in a name?--Pluto