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Pluto: A 'Planet' Or Not?

Pluto

Just so long as we don't forget Pluto's REAL name, "Yuggoth."
 
If the penpushers get their way then it will be downgraded. However, I still say, for sake of scientific discovery and quirks (and so forth), Pluto should remain a planet. BTW, I still say brontosaurus too. Nyah.
 
Planets plan boosts tally to 12
By Paul Rincon
Science reporter, BBC News

The number of planets around the Sun could rise from nine to 12 - with more on the way - if experts approve a radical new vision of our Solar System.

An endorsement by astronomers meeting in Prague would require school and university textbooks to be rewritten.

The proposal recognises eight classical planets, three planets belonging to a new category called "plutons" and the largest asteroid Ceres.

Pluto remains a planet, but becomes the basis for the new pluton category.

The plan has been drawn up by the International Astronomical Union (IAU) with the aim of settling the question of what does and does not count as a planet.

Some 2,500 astronomers gathered at the IAU General Assembly in Prague will vote on the plan next Thursday.

New era

"For the first time in more than 75 years, we will be able to discover new planets in our Solar System. This is a fascinating prospect," said Richard Binzel, a member of the IAU planet definition committee which put together the proposal.

Dr Andrew Coates of the Mullard Space Science Laboratory in Dorking said he thought the plan was "a good compromise".

He explained: "It keeps the idea of eight classical planets, while Pluto is allowed to retain its status. But other objects are allowed in, which I suppose makes life more interesting."

Experts have been divided over whether Pluto - further away and considerably smaller than the eight other planets in our Solar System - deserves the title.

Since the early 1990s, astronomers have found several other objects of comparable size to Pluto in an outer region of the Solar System called the Kuiper Belt.

Some astronomers believe Pluto belongs with this population of "icy dwarfs", not with the objects we call planets.

Allowances could once be made for Pluto on account of its size. At just 2,360km (1,467 miles) across, Pluto is significantly smaller than the other planets. But until recently, it was still the biggest known object in the Kuiper Belt.

That changed with the discovery of 2003 UB313 by Professor Mike Brown and colleagues at the California Institute of Technology (Caltech). After being measured with the Hubble Space Telescope, it was shown to be some 3,000km (1,864 miles) in diameter, making it larger than the ninth planet.

Kicked upstairs?

The IAU draft resolution recognises eight "classical" planets - Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune - three "plutons" - Pluto, Charon and UB313 - and the asteroid Ceres.

Charon is currently described as a moon of Pluto, but because of its size some experts consider it a twin planet.

Professor Owen Gingerich, who chairs the IAU planet definition committee, said: "In a sense we're demoting Pluto by taking it off the list of classical planets. But we're promoting it by making it the prototype of this new category of plutons."

Dr Coates commented: "Something had to be done about the definition. It does change the textbooks somewhat, but it also demonstrates that this is a vibrant area of research.

"The surprise is Ceres, because most people thought of it as an asteroid."

Ceres is the largest object in the asteroid belt between Mars and Jupiter, and like a planet is spherical in shape.

Seeking endorsement

The basis for this re-evaluation is a new scientific definition of a planet which uses gravity as the determining factor.

According to this definition, two conditions must be satisfied for an object to qualify as a planet:


The object must be in orbit around a star, but must not itself be a star
It must have enough mass for the body's own gravity to pull it into a nearly spherical shape
On whether he was confident the resolution would be passed, Professor Gingerich told the BBC News website: "It will be a very awkward situation if they don't.

"On Sunday afternoon, we proposed it out of the blue for the division chairmen and they voted unanimously that they would be prepared to back it. That's a good cross-section of astronomers.

"I'm sure it will be controversial to those with a stake in some other solution, but I hope we will get an overwhelming endorsement."

More objects are likely to be announced as planets in the future. The IAU has a "watchlist" of at least a dozen other potential candidates that could become planets once more is known about their sizes and orbits.

These include the distant objects Sedna, Orcus, Quaoar and 2003 EL61 and the asteroids Vesta, Pallas and Hygiea.

The IAU spent two years debating the matter among its membership. A seven-member committee was set up to consider the findings and produce a draft proposal.

The body has been responsible for the naming of planets and moons since 1919.

http://news.bbc.co.uk/1/hi/sci/tech/4795755.stm
Plutons? Well, OK.
 
So Pluto has been effectively "put down" then? :( (poor Pluto)
 
Mr_Nemo said:
So Pluto has been effectively "put down" then?

No, not really - "Pluto remains a planet." So we now have an eight + four planet or a 12-planet solar system. Take yer cherce. A neat compromise.

p. s. It's just my guess, but I think there's still a Mars-sized thingamajig waiting out there somewhere.

(8 + 4 or 12 - almost sounds like a dance step.
 
Some background on the word Pluton (from World Wde Words):

Turns of Phrase: Pluton
-------------------------------------------------------------------
The same resolution at the International Astronomical Union (IAU)
would officially create this new word as a way of distinguishing
among several classes of bodies orbiting the Sun. The classical
planets are the most massive bodies: Mercury, Venus, Earth, Mars,
Jupiter, Saturn, Uranus and Neptune. There are also large numbers
of small rocky bodies called collectively the minor planets.

In between would be this new class. They are massive enough to have
been formed into a spherical shape by their own gravity, they orbit
the sun so far out that one revolution of the Sun takes at least
200 years, and they have elliptical orbits that are inclined to
those of the classical planets, the implication being that plutons
have a different origin.

The word has been created from the name of Pluto, the ninth planet,
which is from Greek mythology, in which it was a euphemism for the
god of the underworld, Hades. Literally, "pluto" meant "rich one",
in reference to the wealth that came from the Earth. The planet was
famously named as a result of a suggestion by the 11-year-old Miss
Venetia Burney, of Oxford. Walt Disney's dog, by the way, was named
after the planet, not the other way round; popular culture didn't
have the influence it does now, when names like Xena - the Greek
warrior princess of the US television series - can be seriously
considered.

This week's news reports often implied that the committee which put
forward the word had invented it. But there are earlier examples:
the astronomer Tom Burns used it in the same sense in an article in
the Columbus Dispatch in June 1997, as did Frederik Pohl in his SF
novel Mining the Oort of 1992; Robert Heinlein created an Earth
currency of that name in his novelettesGulf (1949) and Tunnel in
the Sky (1955), though that was based on plutonium. "Pluton" is
also an established geological term, for a large body of intrusive
igneous rock beneath the Earth's surface; that was created in the
1930s as a back-formation from the adjective "plutonic", itself
taken from the Greek name, that referred to the action of intense
heat at great depths upon rocks forming the Earth's crust.

* Daily Telegraph, 16 Aug. 2006: Little Pluto, which had been in
peril of losing its place among the planets, keeps its status, but
only in a new category of "plutons," distant oddballs wandering
outside Neptune in weirdly shaped orbits.

* The Seattle Times, 16 Aug. 2006: Dozens more plutons could be
added after the objects are more thoroughly reviewed by the IAU.
 
Astronomers lean towards eight planets

Finally, astronomers could be homing in on a definition of the word planet. After a day of public bickering in Prague, followed by negotiations behind closed doors, the latest draft resolution was greeted with a broadly friendly reception.

If accepted on Thursday, it would be bad news for Pluto, which would no longer be a full-fledged planet.

The crucial change in "draft c" is that a planet must be the dominant body in its orbital zone, clearing out any little neighbours. Pluto does not qualify because its orbit crosses that of the vastly larger Neptune.

The planet definition committee is also stepping back from trying to define all planets in the universe, and sticking to our solar system – a slightly easier task.

It is still a work in progress, however, and the wording will change by Thursday in part to simplify it and make the final result more palatable to the public.

Least unpopular
Terminology is still controversial. Objects that do not quite qualify as planets – because they are big enough to be round but not big enough to dominate their neighbourhoods – might become "dwarf-planets" or planetoids.

These would include Pluto and Ceres, the largest asteroid. And the small fry of the solar system, such as asteroids, might be called small solar system bodies, or retain their current designation as minor planets.

But a supplementary resolution would at least make Pluto the prototype of a class of icy outer worlds beyond Neptune. "The purpose of this is to give a nod to those people who are great Pluto fans," said Owen Gingerich of Harvard University in Massachusetts, US, who is chairman of the committee.

It is not clear what they would be called, however – most early suggestions were rejected by an informal show of hands. Pluton, plutoid, plutonoid and plutid seem to be out of the running, as are "Tombaugh object" and "Tombaugh planet", which had been proposed in honour of Pluto's discoverer, Clyde Tombaugh. "Plutonian object" was the least unpopular choice.

Multiple drafts
The planet definition committee's first draft definition, released last Wednesday, had admitted Pluto, Ceres and probably dozens more objects to planethood by virtue of being round objects orbiting the Sun (see Planet debate: Proposed new definitions).

Then another group of astronomers, many of whom study the dynamics of the solar system, responded on Friday by insisting that a planet must dominate its neighbourhood, which would admit only the eight fully formed planets (see Pluto may yet lose planet status).

At a fractious lunchtime meeting on Tuesday, the committee's first attempt at a compromise met a hostile response. "They have presented practically the same resolution as before," said Julio Fernandez of the University of the Republic in Montevideo, Uruguay, lead author of Friday's proposal.

Secret negotiations
He was cut off when he tried to read his proposal aloud. When more questions were prevented, there was a cry of: "If there is democracy, listen to the questions. Let the people speak!"

Now, although all is not quite sweetness and light, the main sticking point may have been removed, and there is now hope for a positive result at Thursday's vote.

Andrea Milani of the University of Pisa in Italy had fiercely opposed the planet definition committee at the first meeting on Tuesday. But after participating in the private negotiations that afternoon, he told New Scientist: "I'm very satisfied."

http://www.newscientistspace.com/articl ... anets.html
 
Plutos fate is balanced on a knife edge

This afternoon, at around 1300 GMT, astronomers will finally vote on the definition of "planet".

The resolutions they will vote on have been hammered out during a series of often troubled meetings. More specifically, Pluto's status will depend on whether members of the International Astronomical Union vote for resolution 5A or 5B.

If the distinction is made between "planet" and "dwarf planet", Pluto will be effectively demoted. If instead the distinction is made between "classical planet" and "dwarf planet", Pluto's status remains open. This is because in the latter case there will still be no unequivocal definition of the word "planet" so Pluto and the other dwarfs might be considered planets too.

There could just possibly be a late change to the wording. At 0830 GMT, a large group of astronomers invaded the press room waving a piece of paper bearing the word "Planetino", which they propose as an alternative to dwarf planet. But the executive are unlikely to accept the change, as it would seal Pluto's fate – a planetino is clearly not a planet.

http://www.newscientistspace.com/articl ... -edge.html
 
rynner said:
An endorsement by astronomers meeting in Prague would require school and university textbooks to be rewritten.

http://news.bbc.co.uk/1/hi/sci/tech/4795755.stm

University textbooks being one of the biggest rip-off, outright theft type scams out there, I think I see the *real* motive here. Conspiracy by the textbook publishers, anyone? ;)

Though I'm sure today there's great wailing and gnashing of teeth in our local astronomy department. The campus observatory is named after (onetime) Kansas farmboy Clyde Tombaugh. And so Kansas' association with science takes yet another hit... :(
 
You know it makes sense...

Pluto loses status as a planet

Astronomers meeting in the Czech capital have voted to strip Pluto of its status as a planet.


About 2,500 experts were in Prague for the International Astronomical Union's (IAU) general assembly.

Astronomers rejected a proposal that would have retained Pluto as a planet and brought three other objects into the cosmic club.

Pluto has been considered a planet since its discovery in 1930 by the American Clyde Tombaugh.

The ninth planet will now effectively be airbrushed out of school and university textbooks.

The decision was made at a meeting of the International Astronomical Union (IAU) in Prague. The astronomers voted by raising their yellow ballot papers for a count.

"The eight planets are Mercury, Earth, Venus, Mars, Jupiter, Saturn, Uranus and Neptune," said the IAU resolution, which was passed following a week of stormy debate.

Robin Catchpole, of the Institute of Astronomy in Cambridge, told the BBC News website: "My own personal opinion was to leave things as they were; I met Clyde Tombaugh and thought how nice it was to shake hands with someone who had discovered a planet.

"But since the IAU brought out the proposal for new planets I had been against it - it was going to be very confusing. The best of the alternatives was to leave the major planets as they are and then demote Pluto. So I think this is a far superior situation."

Louis Friedman, executive director of the Planetary Society in California commented: "The classification doesn't matter. Pluto - and all Solar System objects - are mysterious and exciting new worlds that need to be explored and better understood."

Pluto's status has been contested for many years as it is further away and considerably smaller than the eight other planets in our Solar System.

Since the early 1990s, astronomers have found several other objects of comparable size to Pluto in an outer region of the Solar System called the Kuiper Belt.

Some astronomers have long argued that Pluto belongs with this population of small, icy "dwarf planets", not with the objects we call planets.

Allowances were once made for Pluto on account of its size. At just 2,360km (1,467 miles) across, Pluto is significantly smaller than the other planets. But until recently, it was still the biggest known object in the Kuiper Belt.

That changed with the discovery of 2003 UB313 by Professor Mike Brown and colleagues at the California Institute of Technology (Caltech). After being measured with the Hubble Space Telescope, it was shown to be some 3,000km (1,864 miles) in diameter, making it larger than the ninth planet.

Named after the god of the underworld in Roman mythology, it orbits the Sun at an average distance of 5.9 billion kilometres (3.7 billion miles) taking 247.9 Earth years to complete a single circuit of the Sun.

An unmanned US spacecraft, New Horizons, is due to fly by Pluto and the Kuiper Belt in 2015.

Story from BBC NEWS:

Published: 2006/08/24 13:34:45 GMT

© BBC MMVI
 
I find this news strangely depressing. Should one feel sorry for a planet?
 
In my opinion, these are the planets of our solar system:

Mercury
Venus
Earth
Mars
Jupiter
Saturn
Uranus
Neptune
Pluto
Telos
Quaor
Sedna

According to a poll I saw, 60% oppose the decision, 13%, support it and 27% don't care.

“What song the Syrens sang, or what name Achilles assumed when he hid himself among women, although puzzling questions are not beyond all conjecture.”
 
theyithian said:
I find this news strangely depressing. Should one feel sorry for a planet?

I imagine some astrologers will be a bit confused now ;)
 
I've no doubt the numerologists are bummed as well, as I believe 9 was/is considered a *mystical* number in various mythologies/cosmologies. Let's find that Planet X and get the number back up to nine! :D
 
I think its for the best really because in the long run Pluto is only one of millions of small icy bodies on the edge of the solar system. Astronomers have already found objects larger than it and its only a matter of time before hundreds if not tens of thousands are found. Does that mean that all of these should be upgraded to planets just to keep Pluto as a planet. Even Ganymede (Jupiters largest moon) is considerably bigger than Pluto. Pluto doesn't even behave like a planet either. In fact the only reason it was considered a planet in the first place is because it was found in 1930. I dare say that if it was discovered any later than 1960 or 70 it never even would have been considered as a planet.
 
Pluto vote 'hijacked' in revolt

A fierce backlash has begun against the decision by astronomers to strip Pluto of its status as a planet.
On Thursday, experts approved a definition of a planet that demoted Pluto to a lesser category of object.

But the lead scientist on Nasa's robotic mission to Pluto has lambasted the ruling, calling it "embarrassing".

And the chair of the committee set up to oversee agreement on a definition implied that the vote had effectively been "hijacked".

The vote took place at the International Astronomical Union's (IAU) 10-day General Assembly in Prague. The IAU has been the official naming body for astronomy since 1919.

Only 424 astronomers who remained in Prague for the last day of the meeting took part.

An initial proposal by the IAU to add three new planets to the Solar System - the asteroid Ceres, Pluto's moon Charon and the distant world known as 2003 UB313 - met with considerable opposition at the meeting. Days of heated debate followed during which four separate proposals were tabled.

Eventually, the scientists adopted historic guidelines that see Pluto relegated to a secondary category of "dwarf planets".

Drawing the line

Dr Alan Stern, who leads the US space agency's New Horizons mission to Pluto and did not vote in Prague, told BBC News: "It's an awful definition; it's sloppy science and it would never pass peer review - for two reasons.

"Firstly, it is impossible and contrived to put a dividing line between dwarf planets and planets. It's as if we declared people not people for some arbitrary reason, like 'they tend to live in groups'.

"Secondly, the actual definition is even worse, because it's inconsistent."

One of the three criteria for planethood states that a planet must have "cleared the neighbourhood around its orbit". The largest objects in the Solar System will either aggregate material in their path or fling it out of the way with a gravitational swipe.

Pluto was disqualified because its highly elliptical orbit overlaps with that of Neptune.

But Dr Stern pointed out that Earth, Mars, Jupiter and Neptune have also not fully cleared their orbital zones. Earth orbits with 10,000 near-Earth asteroids. Jupiter, meanwhile, is accompanied by 100,000 Trojan asteroids on its orbital path.

These rocks are all essentially chunks of rubble left over from the formation of the Solar System more than four billion years ago.

"If Neptune had cleared its zone, Pluto wouldn't be there," he added.

Stern said like-minded astronomers had begun a petition to get Pluto reinstated. Car bumper stickers compelling motorists to "Honk if Pluto is still a planet" have gone on sale over the internet and e-mails circulating about the decision have been describing the IAU as the "Irrelevant Astronomical Union".

'Inconvenient arrangements'

Owen Gingerich chaired the IAU's planet definition committee and helped draft an initial proposal raising the number of planets from nine to 12.

The Harvard professor emeritus blamed the outcome in large part on a "revolt" by dynamicists - astronomers who study the motion and gravitational effects of celestial objects.

"In our initial proposal we took the definition of a planet that the planetary geologists would like. The dynamicists felt terribly insulted that we had not consulted with them to get their views. Somehow, there were enough of them to raise a big hue and cry," Professor Gingerich said.

"Their revolt raised enough of a fuss to destroy the scientific integrity and subtlety of the [earlier] resolution."

He added: "There were 2,700 astronomers in Prague during that 10-day period. But only 10% of them voted this afternoon. Those who disagreed and were determined to block the other resolution showed up in larger numbers than those who felt 'oh well, this is just one of those things the IAU is working on'."

E-voting

Professor Gingerich, who had to return home to the US and therefore could not vote himself, said he would like to see electronic ballots introduced in future.

Alan Stern agreed: "I was not allowed to vote because I was not in a room in Prague on Thursday 24th. Of 10,000 astronomers, 4% were in that room - you can't even claim consensus.

"If everyone had to travel to Washington DC every time we wanted to vote for President, we would have very different results because no one would vote. In today's world that is idiotic. I have nothing but ridicule for this decision."

He added that he could not see the resolution standing for very long and did not plan to change any of the astronomy textbook he was currently writing.

But other astronomers were happy to see Pluto cast from the official roster of planets. Professor Iwan Williams, the IAU's president of planetary systems science, commented: "Pluto has lots and lots of friends; we're not so keen to have Pluto and all his friends in the club because it gets crowded.

"By the end of the decade, we would have had 100 planets, and I think people would have said 'my goodness, what a mess they made back in 2006'."

Shaking hands

Robin Catchpole, of the Institute of Astronomy in Cambridge, UK, said: "My own personal opinion was to leave things as they were. I met Clyde Tombaugh, who discovered Pluto, and thought, it's nice to shake hands with someone who discovered a planet.

"But since the IAU brought out the first draft resolution, I was rather against that because I thought it was going to be very confusing. So the best of the alternatives was to keep the eight planets as they are, and then demote Pluto. I think this is a far superior solution."

The need for a strict definition was deemed necessary after new telescope technologies began to reveal far-off objects that rivalled Pluto in size.

The critical blow for Pluto came with the discovery three years ago of an object currently designated 2003 UB313. Discovered by Mike Brown and colleagues at the California Institute of Technology, 2003 UB313 has been lauded by some as the "10th Planet".

Measurements by the Hubble Space Telescope show it to have a diameter of 3,000km (1,864 miles), a few hundred km more than Pluto. 2003 UB313 will now join Pluto in the dwarf planet category.

Mike Brown seemed happy with Pluto's demotion. "Eight is enough," he told the Associated Press, jokingly adding: "I may go down in history as the guy who killed Pluto."

http://news.bbc.co.uk/1/hi/sci/tech/5283956.stm
 
rynner said:
What a great bun-fight! :D :D :D


My planet's bigger than your planet!

Yeah? well my research grant is bigger than yours!

Well. my dad's bigger than yours!

-

Next on the agenda: Is there inteliigent life on Earth?.

-
 
Don't forget the lawyers (wait, they are the undead...) :lol:
 
Astronomers plot to overturn planet definition

Pluto's status could shift yet again, as astronomers are mounting a grassroots campaign to readdress the definition of a planet.

More than 300 researchers have signed a statement denouncing the recently adopted definition that relegates Pluto to "dwarf planet" status, and some are planning a conference in 2007 to hash out an alternative definition.

Last week, scientists at a meeting of the International Astronomical Union (IAU) in Prague, Czech Republic, voted to approve a new planet definition that recognises only eight planets.

But many astronomers find fault with the new definition's criteria – which state a planet must have cleared out the neighbourhood around its orbit. There have also been complaints about the small number of scientists allowed to vote on the issue (see New planet definition sparks furore).

Categorical imperative
Now, disgruntled astronomers are planning a conference to fix what they see as a flawed definition. One of the conference organisers is Alan Stern, who heads NASA's New Horizons mission to Pluto.

He says there will be about 20 planetary scientists organising the meeting, which could be attended by 1000 astronomers. It would probably occur in mid-2007, although there could be smaller working meetings ahead of the conference itself.

Stern says the definition is important because categorising things is a key part of science. "As scientists, part of our job is to reduce the mass of facts to a smaller number of concepts," he told New Scientist.

Official designation
The IAU is responsible for naming solar system objects like planets and their moons, so its definition of a planet is the official one.

It is possible that the definition could be revised at the next IAU general assembly meeting in 2009, but in the meantime teachers and textbook writers are wondering how to explain the concept and which objects to include in descriptions of the solar system.

"Teachers are writing me saying, 'We don't know how to teach this,'" Stern says. "We've got to help them out of this jam that the IAU has put them in."

Conference co-organiser Owen Gingerich of Harvard University in Cambridge, Massachusetts, US, says a definition other than the one decided by the IAU could win out in practice if more textbook authors choose to use it.

De facto definition
Gingerich chaired the IAU committee that recommended a definition that would have included 12 planets – a proposal that was rejected at last week's meeting.

"If the conference is broadly enough representative with the key players, then it may well be that it establishes a different nomenclature than what has been officially voted on by the IAU," he told New Scientist. "It might achieve a more satisfactory consensus."

The IAU so far does not have any plans to revisit the definition before the 2009 meeting, says incoming IAU vice president Martha Haynes of Cornell University in Ithaca, New York, US.

"I don't think there's been any discussion of that in any official sense," she says, noting that the issue could also potentially be discussed at an upcoming meeting of the American Astronomical Society's Division of Planetary Sciences (DPS) in October 2006.

Email voting
But she says the IAU may change its voting policy to allow more members to have their say in official decisions, including the contentious issue of what constitutes a planet.

Only scientists who were physically present in the IAU meeting room in Prague last Thursday were allowed to vote, a restriction that some astronomers say is unfair. She says allowing votes by email might be considered for future IAU decisions.

"I'm sure there will be discussion of whether we could do things better," Haynes told New Scientist. “I'm a strong supporter of processes which are transparent and inclusive, and I am sure the executive committee will give the IAU process a careful review.”

Meanwhile, the DPS issued a statement on Thursday saying it recognises the IAU's authority to decide on a planet definition. But it added that "future refinements of this definition will almost certainly be desired. Ultimately, the definition of a planet will come through common usage and scientific utility."

http://www.newscientistspace.com/articl ... ition.html
 
Anyone got any mnemonics since I had to throw all my planet ones out...
 
Um, so what do we have now...

Mercury, Venus, Earth, Mars, Ceres, Jupiter, Saturn, Uranus and Neptune, Pluto, Charon and UB313...

MVEMCJSUNPCU

Mother Violet Eats Mulberry Crean Just So...Ullyses Never Pinches Coloured Underpants...

that's not quite there yet is it :(
 
At present there are only 8 planets

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

Ceres, Pluto & Charon, UB313 have been downgraded although technically speaking Ceres and UB313 were never considered planets in the first place, they were going to be upgraded in order to keep Pluto as a planet but this idea was not passed instead pluto was downgraded.

It would be interesting to see what percentage of the people trying to keep Pluto as a planet are American because i remember reading an article before (i can't remember where) that American Astronomers really wanted to keep Pluto as it was the only planet discovered by an American. From what i've read about Clyde Tombaugh himself it seems like he would not really care if Pluto was downgraded.
 
Planet Eris

The late Eris Andys would be proud...

http://news.bbc.co.uk/1/hi/sci/tech/5344892.stm

Last Updated: Thursday, 14 September 2006, 10:51 GMT 11:51 UK

Astronomers name 'world of chaos'

Eris gave rise to discord within the astronomical community
The distant world whose discovery prompted leading astronomers to demote Pluto from the rank of "planet" has now been given its own official name.
Having caused so much consternation in the International Astronomical Union (IAU), the object has been called Eris, after the Greek goddess of discord.

Eris is larger than Pluto, which put scientists in the fix of having to call them both planets - or neither.

Both bodies have now been put in the new classification of "dwarf planets".

Eris' discoverer, Michael Brown of the California Institute of Technology, told the Associated Press that the name was an obvious choice, calling it "too perfect to resist".

In mythology, Eris caused a quarrel among goddesses that sparked the Trojan War. In real life, Eris also caused strife, forcing scientists to produce a strict definition of the term planet - and that eventually led to Pluto losing the status it had held since its discovery in 1930.

The need for a strict definition was deemed necessary after new telescope technologies began to reveal far-off objects that rivalled Pluto in size.


ERIS - WORLD OF DISCORD

First seen in 2003 but finally recognised in 2005
Highly elongated orbit around Sun lasting 560 years
Currently positioned some 14.5 billion km from Earth
Has extremely frigid surface temperature of -250C
May have thin atmosphere when closest to Sun
Is accompanied by a satellite now given the name Dysnomia
Without a new nomenclature, these discoveries raised the prospect that textbooks could soon be talking about 50 or more planets in the Solar System.

That prospect proved too much for IAU members who took the historic decision last month to redefine the Solar System.

Eris - initially given the codename "Xena" after a TV character - was discovered on 8 January, 2005, at the Palomar Observatory in California.

Its exact size is difficult to measure, being small and faint; Brown's team, using the Hubble telescope, found the object's diameter to be just 70km bigger than Pluto's. Another team, using a radio telescope in Spain, has measured Eris to be some 700km larger than Pluto.

Eris has a moon, and this too now has an official name: Dysnomia, the daughter of Eris known as the spirit of lawlessness.

The "new" Solar System agreed at the IAU's General Assembly has eight planets - Mercury to Neptune - and at least three dwarf planets: Pluto, Eris and the largest asteroid in the Solar System, Ceres.

Astronomers opposed to Pluto's demotion have launched a petition to try to get it reinstated.
 
Re: Planet Eris

owenwhiteoak said:
Astronomers opposed to Pluto's demotion have launched a petition to try to get it reinstated.
After 76 years of sterling service to the solar system, the very least we should do is make Pluto an "honorary planet". Let Ceres, Eris, Sedna, Nesbitt, Uncle Tom Cobley and the rest fight it out for supremacy in the dwarf planet stakes, but not poor old Pluto.

Anyway, should they not be "planets of restricted growth"? Or "midget planets"?

Actually, and don't tell them I said so, but I was never very happy that the gas giants were considered proper planets. They might be big, but substantial they ain't. Bloody gaseous upstarts! We should go back to calling them "wandering stars", if you ask me.

So that leaves four planets - Mercury, Venus, Earth and Mars - one honorary planet, four wandering stars and any number of plidgets.

Don't thank me - I'm just glad to have finally sorted out the solar System's latest identity crisis.
 
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