Demote The IAU!!!!

johns805 · Aug 24, 2006

Take up the cry!!! Demote The IAU!!!! I'm mad as hell and I'm not going to take it anymore!!! Give Me Nine Planets Or Give Me Death!!! Harumph!!!!

MeteorWayne · Aug 24, 2006

Ahh, shaddap and move to Pluto if ya like it so much. Harrumph!!! Harrumph!!! <img src="/images/icons/tongue.gif" /> <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

Saiph · Aug 24, 2006

and why are you so attached to having pluto as a planet? <div class="Discussion_UserSignature"> --------------------SaiphMOD@gmail.com -------------------"This is my Timey Wimey Detector. Goes "bing" when there's stuff. It also fries eggs at 30 paces, wether you want it to or not actually. I've learned to stay away from hens: It's not pretty when they blow" -- The Tenth Doctor, "Blink" </div>

Philotas · Aug 24, 2006

I would like to ask what people have against having Pluto as a planet. <img src="/images/icons/tongue.gif" /> <div class="Discussion_UserSignature"> </div>

Saiph · Aug 24, 2006

1) It's composition is quite unlike the other terrestrial planets. 2) It's density and differentiation are unlike other terrestrial planets. 3) It's orbit is very eccentric compared to all other planets. 4) It is not a "dominant" object in it's orbital region. <div class="Discussion_UserSignature"> --------------------SaiphMOD@gmail.com -------------------"This is my Timey Wimey Detector. Goes "bing" when there's stuff. It also fries eggs at 30 paces, wether you want it to or not actually. I've learned to stay away from hens: It's not pretty when they blow" -- The Tenth Doctor, "Blink" </div>

MeteorWayne · Aug 24, 2006

Thanx for summing it up. These have always been my arguments. Can't wait for the next public night at the observatory. Should be a doozy! <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

ittiz · Aug 24, 2006

I just did the calculations and relized Neptune isn't a planet. Since it's orbit crosses Pluto's and it's only 21 times its size. That means Netune must not be a planet. Boy they should have thought this through a little better.

MeteorWayne · Aug 24, 2006

Neptune only 21 times bigger than Pluto? OK, off to the books. <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

ittiz · Aug 24, 2006

Neptune's Diameter: 49,528km. Pluto's Diameter: 2306km. 49,528km/2306km= 21.477

rhm3 · Aug 24, 2006

1) It's composition is quite unlike the other terrestrial planets. So Jupiter, Saturn, Uranus, and Neptune are out? If a lone Earth-sized object made of ice was discovered, it wouldn't be a planet? 2) It's density and differentiation are unlike other terrestrial planets. See above. This really doesn't matter. 3) It's orbit is very eccentric compared to all other planets. So are several Jupiter-mass objects orbiting other stars. 4) It is not a "dominant" object in it's orbital region. Fair point, but define orbital region and orbital dominance. (not trying to put you on the spot here, the IAU failed to specify this too). And anyways I don't see why this should matter...what difference would it make if Earth in a region with other round objects?

MeteorWayne · Aug 24, 2006

You are correct, sir, However, I believe the difference is defined in mass. There the ratio is ~6890/1 <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

ittiz · Aug 24, 2006

Could be, but the definition doesn't seem to indicate that. We have to wait to see exactly what they mean by "size," which usually refers to external dimensions. It's also possible they mean volume as well. But by "size" I think they mean size and if that's the case Neptune isn't a planet.

MeteorWayne · Aug 24, 2006

You are right, the definition does not clearly state that at all. However, since most of the "clearing out" that a (here I go using that term again <img src="/images/icons/smile.gif" /> ) planet does is based on mass, I would think that is what will be used. Only my opinion. It is not explicitely stated in the passed resolution, which means we'll have MONTHS to speculate here! <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

rfoshaug · Aug 24, 2006

A very good post, RHM3! I agree totally. To have "orbital dominance" is increasingly more difficult the farther out you get in the solar system. What happens if we find an Earth-sized object at 100 AU from the Sun? If there are other round objects in that region, shouldn't it be called a planet? This definition certainly won't make anything any easier when it comes to planets orbiting other stars. <div class="Discussion_UserSignature"> ----------------------------------My minds have many opinions </div>

MeteorWayne · Aug 24, 2006

This definition certainly won't make anything any easier when it comes to planets orbiting other stars. It's not intended to, referring to the sun. I'm not sure it would be a good idea to try and define other star systems yet. />We're having enough trouble with ours. />We really don't have a good census of what's out there yet. We've only detected large "planets" in short orbits. Yeah, getting smaller, and longer orbits all the time, but we're really at the very beginning of this process. Give it a decade before we try defining other star systems <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

Saiph · Aug 24, 2006

first, pluto is solid, and thus cannot be compared directly to the jovian planets. Second, composition does matter when we are trying to classify objects. While one may be able to classify it as a planet, you cannot classify it as a terrestrial planet when the only trait it shares is the fact that it's solid, and not gaseous. 2) Density and differentiation do matter, if these major traits are not shared by a candidate planet. 4) If there were lots o similar sized objects, I'd say it was a member of a belt...but not a planet of it's own. The thing is, earth is big enough that any other objects in it's orbital region would be swept up (or away). The presence of similar objects would be a temporary factor. This will hold regardless of distance from the center. Earth will have a clear band of material in it's orbital area even at pluto's distance. Especially since it'd have 4.5 billion years to clear it out. Now, I Ignored 3, because of hte point I have here: None of these criteria are an all or nothing deal. But because pluto fails all of them, let alone most, it really isn't a terrestrial planet. Now, as for the comment that Neptune is only 21x larger than Pluto...okay, sure. But it's also far larger than Earth too. And it's much more massive. <div class="Discussion_UserSignature"> --------------------SaiphMOD@gmail.com -------------------"This is my Timey Wimey Detector. Goes "bing" when there's stuff. It also fries eggs at 30 paces, wether you want it to or not actually. I've learned to stay away from hens: It's not pretty when they blow" -- The Tenth Doctor, "Blink" </div>

rhm3 · Aug 24, 2006

first, pluto is solid, and thus cannot be compared directly to the jovian planets. Right, but then neither can the terrestrial planets. My point is there are some huge differences between terrestrial and giant planets, but I don't see fuss over separating them. Second, composition does matter when we are trying to classify objects. While one may be able to classify it as a planet, you cannot classify it as a terrestrial planet when the only trait it shares is the fact that it's solid, and not gaseous. That depends on what you consider terrestrial. I personally consider terrestrial planets to be midway in size between giant and dwarf, regardless of composition. (upper and lower limits both based essentially on atmospheric capabilities) 4) If there were lots o similar sized objects, I'd say it was a member of a belt...but not a planet of it's own. The thing is, earth is big enough that any other objects in it's orbital region would be swept up (or away). The presence of similar objects would be a temporary factor. That may be a premature assumption. I read recently (from someone here?) that the presence of Jupiter and the other giant planets made it easier for the smaller terrestrial planets to clear their regions. This is because Jupiter crammed the planetessimals/protoplanets in a limited area...so although there were probably dozens of protoplanets to begin with, their close proximity ensured that only a few would survive the chaos. Now, it is said the KBOs were forced outward from the changing orbits of the giant planets. Since there are no more giant planets that formed in this stage out there, they had a TON of wiggle room...look how vast the distance is from Neptune to the Oort Cloud. With no giants to limit the KBOs, they were able to grow a bit bigger than the asteroid belt and I suspect there are several that rival the inner terrestrial planets. My point is, in other st

Saiph · Aug 24, 2006

the fact that a large jovian (i.e. jupiter) makes it easier for smaller terrestrial planets to clear their region only shortens the time scale required. I'm sure earth would have cleared the area even if jupiter wasn't there. the problem with calling pluto terrestrial is that of all the terrestrial planets, it differs in almost every major trait from all the other terrestrial planets. So it's really only distantly related at best. <div class="Discussion_UserSignature"> --------------------SaiphMOD@gmail.com -------------------"This is my Timey Wimey Detector. Goes "bing" when there's stuff. It also fries eggs at 30 paces, wether you want it to or not actually. I've learned to stay away from hens: It's not pretty when they blow" -- The Tenth Doctor, "Blink" </div>

cuddlyrocket · Aug 24, 2006

The IAU definition states that a planet has 'cleared the neighbourhood around its orbit' and that Mercury, Venus, Earth, Jupiter, Saturn, Uranus and Neptune are the eight planets in our Solar System (note the definition does not say the 'eight known planets' - it's an exhaustive list, there are no other planets in the Solar System). Therefore even though the precise meaning of 'cleared the neighbourhood around its orbit' is unclear, of all the possible definitions, only those that mean that Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune have cleared the neighbourhood around their orbits, and that no other object that is in orbit around the Sun and has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape has cleared the neighbourhood around its orbit, are valid. It might be that there is no definition of 'cleared the neighbourhood around its orbit' that is valid, in which case the definition of planet is internally self-contradictory and the IAU will have to go back to the drawing board!

Philotas · Aug 25, 2006

Terra means Earth. That measn that terrestrial planets simply are Earth-like planets. Alllow me to cite wikipedia: A terrestrial planet or telluric planet is a planet that is primarily composed of silicate rocks. The term is derived from the Latin word for Earth, "Terra", so an alternate definition would be that these are planets which are, in some notable fashion, "Earth-like". http://en.wikipedia.org/wiki/Terrestrial_planet Pluto is icy, thus it has never ment to be classified as a terrestrial planet. <div class="Discussion_UserSignature"> </div>

Philotas · Aug 25, 2006

If they meant volume, it would say mass. Size is mainly referred to as diameter. <div class="Discussion_UserSignature"> </div>

torino10 · Aug 25, 2006

Has it occured to anybody that by raising the bar so high for planetary classification that they have reduced the number of people who will be interested in looking for Planets? Not only has the IAU shot itself in the foot by reducing intersest and consequently budgets, but with the inclusion of the 'sweeps objects out of its path' pretty much makes it useless to look for planets were possible Earth Impactors may be found.

alokmohan · Aug 25, 2006

http://www.int.iol.co.za/index.php?set_id=1&click_id=31&art_id=qw1156488301752S122&newslett=1&em=52618a6a20060825ah

MeteorWayne · Aug 25, 2006

I'll have to check my Animaniacs tapes for how they handles Pluto <img src="/images/icons/smile.gif" /> <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

alokmohan · Aug 25, 2006

Hope you succeed.

Demote The IAU!!!!

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