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Fraser
2004-Nov-10, 07:17 PM
SUMMARY: Is Pluto a planet or just a really large Kuiper Belt Object (KBO)? Those arguing that it doesn't deserve planetary status will have to reconsider because of new research from the Spitzer Space Telescope. It was previously believed that KBOs were fairly dark, with a similar reflectivity to comets. From the reflectivity, astronomers guessed that KBOs are quite large, some getting as big as 700 km (434 miles) across. But new observations from Spitzer show that they're probably more reflective than previously thought, and therefore much smaller. This means that Pluto is probably still significantly larger than other objects in the Kuiper Belt.

What do you think about this story? Post your comments below.

GOURDHEAD
2004-Nov-10, 08:37 PM
Whether Pluto or other transneptunian objects are called planets doesn't seem to be very important. Determination of their orbits and sizes is of great importance.

lswinford
2004-Nov-10, 09:22 PM
Because of the distortion common to the projection, on most earth maps Greenland looks larger than Australia, but it is not. The planetary label belongs to things behaving like planets, and Pluto does. Kuiper Belt asteroids or proto-cometary objects are minor accretions of the solar system's residual debris. Objects the size of Pluto, whether in fact an escaped moon or not (its orbit may two-dimensionally cross but supposedly does not intersect with Neptune because of its inclination), is the controlling mass to another moon and a substantial accretion body in its own right. Australia may be the smallest continent and Pluto the smallest planet. Pluto has an atmosphere with nitrogen, carbon monoxide, and methane detected. It has seasonal ice caps. All of this, however, keys on how it was made. Not merely its size. If the asteroid camps were the pumice-like ejecta from objects colliding with or otherwise crushed and fragmented by what are now planets or moons, then they are the cracker crumbs of the solar system. If they were the consolidating solar system sweepers that absorbed and incorporated the solids of our solar system's accretion disk in a comparative unified whole and are the primary center of gravity for the zone of space it swings through, then that sounds like a planet. Similarly, as the mooned planets demonstrate, smaller bodies that are captured and controlled by those planetary bodies are moons. So far, it seems that the Kuiper belt objects may, as with asteroids between Mars and Jupiter may congregate in relative vicinities, but they are not significant system-controlling bodies--at least as current pictures seem to indicate. So, for what its worth, is my opinion. B)

Janice
2004-Nov-10, 11:00 PM
Does it really matter if Pluto is a planet? :rolleyes: I mean what we call it doesn't adversely effect any research into it or, for that matter anything else really. :P So why are people taking this so seriously? :huh:

StarLab
2004-Nov-11, 01:47 AM
Because in the near future, children won&#39;t want to memorize the Fifteen Planets of the Solar System. ;) :rolleyes: <_< :lol: B) :ph34r: :unsure: :blink: :huh: :o :D :P

Janice
2004-Nov-11, 03:00 AM
:lol: Cute, StarLab, Very Cute. :D

om@umr.edu
2004-Nov-11, 03:13 AM
I agree with Janice and Gourdhead.

It really doesn&#39;t matter what label you give Pluto. The label does not determine its nature.

Far more important, IMHO, is how did it form and what is it made of?

Once we know that, we might be in a position to decide if "planet" is the appropriate label.

With kind regards,

Oliver
http://www.umr.edu/~om

lswinford
2004-Nov-11, 09:34 PM
Janice is right, and so is StarLab. If we are going to make distinctions it will need to be more functional than some arbitrary size or mass line in the sand. Besides ;) I&#39;m having a hard time figuring out some mnemonic crutch to include KZ2013 from the other things that orbit the sun :D .

spacepunk
2004-Nov-12, 03:43 AM
If they were the consolidating solar system sweepers that absorbed and incorporated the solids of our solar system&#39;s accretion disk in a comparative unified whole and are the primary center of gravity for the zone of space it swings through, then that sounds like a planet
Also, quote from the UT forum "retrograde Venus"
http://www.universetoday.com/forum/index.p...retrograde&st=0 (http://www.universetoday.com/forum/index.php?showtopic=1559&hl=venus%20retrograde&st=0)

(2) The more commonly accepted hypothesis is that Venus suffered a glancing blow by a Mars Ė Venus size object during its formation. We know that all of the planets suffered these large collisions in the first 100 million years of their formation. In fact, thatís how the Moon was formed. These early giant impacts also explain why Uranus is tipped 98 degrees on its axis. Large planet-planet encounters would have been the final stage of major accretion, reducing the solar system from two dozen or so planet-size objects on crossing orbits to the 8 slightly larger planets we have today. Planet-planet collisions appear to be the only events dynamically capable of producing such dramatic tilts of Venus, Earth, Saturn, and Uranus. The object that hit Venus could also have stolen a lot of Venusí angular momentum in the same way we steal angular momentum from planets for spacecraft gravity assists. The large mass of the intruding object could account for the slow spin of Venus. If it slowed Venusí rotation rate to near zero, then the tidal effects mentioned in hypothesis #1 might be able to finish the job and change the rotation from prograde to retrograde; or the encounter itself might have tipped Venus more than 90 degrees on its axis and solar torques eventually pulled the axis to its current 177 degree (nearly vertical) orientation.Dr. Wood
and a discussion of what altered Venus&#39; orbit became absorbed by that planet rather than continuing on to Earth to cause the Moon&#39;s formation http://adsbit.harvard.edu/cgi-bin/nph-iart...p;filetype=.pdf (http://adsbit.harvard.edu/cgi-bin/nph-iarticle_query?1987JBAA...98...23D&data_type=PDF_HIGH&type=PRINTER&filetype=.pdf)



Also with reference to other forums ("What is a planet") It would seem that KBO&#39;s are residual protoplanets from the chaotic pinball formation of the solar system, with an exception being Pluto having actualy attained the status of planet. Anything smaller than a protoplanet would be a comet or unconsolidated material remaining in the much farther Oort cloud. Where does this leave the distinction of the Moon, if at one time it was a Mars-like object but now reduced in size?

Planetwatcher
2004-Nov-13, 08:08 PM
Does it really matter if Pluto is a planet?* I mean what we call it doesn&#39;t adversely effect any research into it or, for that matter anything else really.* So why are people taking this so seriously?*
The reason is that a body which is considered a planet is more likely to receive the scientific study it deserves. Which in order to do that the funding has to be justified. People who fund such missions fall into three catagories.
1, Investers
2, Taxpayers
3, Congress or Parlament (depending on what country you are from)

All three groups want the most bang for their buck, and all three are very difficult to impress, Although IMH Congress is the hardest to get to open the billfolds.

So it is really more a marketing stragigy then anything else. Think about it. How likely are you to okay a hundred gazillion dollars, or pounds, or marks, or whatever your currency is called to send a probe out to explore a hardly significant KBO called 2002 LM60?
Now on the other hand, what if we want to spend the same amount of money to explore a newly discovered planet called Quaoar?

Doesn&#39;t exploring a planet called Quaoar sound more intriquing then a KBO known as 2002 LM60?

It shouldn&#39;t because 2002 LM60 is the official designation for Quaoar. In other words the two are one and the same. But one sounds more intriquing, more explorible, more personal then the other. Why?
Because we made it a planet and gave it a name. This is one of the most successful marketing ploys ever developed. Change what your product is called when compared to the other simular products, and make it bigger, prettier, farther, more interesting, and better then the other products which are simular.

The only marketing tool which comes close to this one is the new and improved ploy. I will demonstate.

Announcing, the newest and most improved innovation in Kupier Belt Objects,
The planet SEDNA . Now bigger, farther, redder, and more interesting then Quaoar, or even the well known KBO Varuna. Get it now&#33;&#33; at your friendly neighborhood local NASA Space Center. Just send a check or money order for ONLY two hundred gazillion dollars to National Space and Aironotics Administration Florida, USA.
Good only while supplies of new KBOs last.

See what I mean. Almost makes you grab an envolope and start looking for your check book.


We currently have terrestrial planets, and gas giant planets. And this is why I propose we should have a third class of planets.

Call them outer planetoids, Kupier planets, whatever you want. Set a lower limit on size 800 to 900 Km for example, and whatever is found as big or bigger is added to this new class of planets.

Janice
2004-Nov-15, 12:42 AM
:o Uh, Thanks Planetwatcher, that&#39;s a really good point from one of the people who obviously takes this at least a little seriously. :)
:lol: P.S. You sure showed me&#33; :D