Pluto and the IAU - What do you think?

Chrissyo (Chris) · #1 15-04-2007, 02:58 AM

Hi everyone. (To mods, is this in the right section? Move if desired

).

During my usual scoot through the Internet, I have run into quite a lot of people who are against the IAU's decision to change Pluto's status. I just spent a bit of time on YouTube watching a few of the videos there. Now I'm completely in favour of the IAU's decision, and I believe it was a practical and sensible move. However, it seems that the majority of the public would disagree with me. So I got to thinking that it might be fun to create my own YouTube (or similar) video discussing my view on the matter. Hopefully I'll get myself thinking, learn some new stuff and maybe get others thinking/learning as well.

Anyway, I thought I would start by having a look at what people think. What does the IceInSpace community think of the IAU's decision? More specifically, do you agree with the IAU's decision on removing Pluto and what are your reasons?

The IAU's resolution for planetary status can be found here: http://www.iau.org/Resolutions_5-6.398.0.html.

I will add polling options to this thread (if I can work out how

) and follow the progress of this thread. There's nothing quite like a good discussion

Astroman (Andrew Wall) · #2 15-04-2007, 08:05 AM

I am 100% with the IAU's decision. Reason being I have never thought of Pluto as the 9th planet and never will. It's inclination to the "orbital plane" is more like an Astreroids than a planets. Although there are quite a few Asteroids that do have a similar inclination to that of the other planets, I believe these to be unformed planets (unable to clump together gravitationally) or a planet who met its end in a catastrophic event. Hard to say without historical evidence from them.

I can see this thread stirring up some pretty interesting debate, but we must remember that it is of the opinion of the poster for their decision and isn't meant to be a sling match between who thinks they are right or wrong.

[1ponders] (Paul) · #3 15-04-2007, 10:30 AM

I agree that scientifically it should not be a planet, though I do see cause to give it a special designation as a planet for purely historical reasons.

rogerg (Roger) · #4 15-04-2007, 05:13 PM

I voted No because...

While it may end up being a correct vote, I don't believe we have a large enough sample space of known planets, let alone the ones between the sizes of Earth & Pluto to accurately decide what we should deem a planet.

In the mean time, we may as well leave Pluto as a planet for historical reasons and not being sure of a better alternative.

iceman (Mike) · #5 16-04-2007, 06:24 AM

I agree with Paul, never considered it a planet but think that it probably should remain named one for posterity.

AJames · #6 16-04-2007, 08:07 AM

This is my view...

The initial discovery of Eris was from very start embroiled in much controversy, mainly because it was soon realised that this latest trans-Neptunian body seemed even larger than Pluto’s diameter. Some astronomers immediately and boldly considered and declared Eris as the long-antisipated new 10th planet of our Solar System. Yet others seem to have some real doubts about this proposal.

For a short while, most remained unsure about the real planetary nature of Eris, mainly because of its considerable faintness and its very slow movement against the background stars. At first Eris was to be considered the 10th planet of our solar system, but probably with some justification, this was soon was diminished, by the new definition of dwarf planet or Scattered Disk Object (SDO).

The unfortunate problem with the newly discovered Eris was that it immediately got caught in a real pre-existing debate on what the actual definitions of what either the term planets or asteroids meant. This particular question had slowly been simmering for the previous decade or so, with many putting their case on either side of the argument. The debate when up a notch or two after about 1993, when significant new discoveries were made of several small to medium-sized planetary bodies found beyond the orbit of Neptune. Some did suggest this region was an unknown second asteroid belt - within the area of the solar system known as the Kuiper Belt. As others soon quickly suspected, Pluto and 2003 UB313 might just the largest examples of a region of hundreds, if not thousands of similar sized bodies. If this were true, then Pluto’s punitive size would made it necessary to denounce its planetary status.

A sometimes torrid and passionate debate ensued for several more years among the planetary astronomers, which wasn’t resolved until the late-August 2006 at the 26th (XXVII) I.A.U. General Assembly Meeting in Prague. On the very last day of this conference it was surprisingly decided, amid much dissension and complaint, to downgraded Eris, Pluto and the minor planet Ceres into a new class of bodies known as dwarf planets. This decision effectively make Eris to be among the numbered planetary bodies. Ie. (136199) Eris, joined by both (134340) Pluto and Ceres.

It was also announced that other dwarf planets will likely be added to this list, especially after the newly discovered trans-Neptunian bodies are discovered.

If Pluto was to be considered a real planet, then surely the new body 2003 UB 313 was also large enough to be classed as a small planet?

Clearly it is not. This is really a necessary evil to divide the asteroids from the planets - and eliminate those that happen to "falling between the cracks." So from 24th August 2006, the official number of planets - Mercury to Neptune - is now reduced to only eight planets - removing Pluto after 76 years as a unique planetary body. It won't be changed again - unless of course another solar system body is found larger than, say, Mercury.

Seven planets anyone?

Dujon · #7 16-04-2007, 10:41 AM

It is quite evident that our forefathers thought with wise and meaningful forethought and got it wrong. The solar system should, surely, begin and end with 'S, U and N'.

Pluto for all those years has been a pimple on the face of our planetary system. Now it has been lanced and reduced to the dwarf that it really is. Perhaps, if we massage it with sun cream for long enough, it will just disappear and we can settle down to ignoring everything else that might intrude upon our understanding of our local environment.

ving (David) · #8 16-04-2007, 10:58 AM

we just do not know enough about our own system and other systems to be able to properly say yes it is or no it isnt. it was called a planet and so it should remain till we can more properly discover what else there is out there to compare it to.
thousands or even millions of textbooks are now wrong and the IAU could be found to be wrong due to thier lack of knowledge.
is a ball of gas really a planet?

higginsdj · #9 16-04-2007, 02:24 PM

Given that we have discovered more than 350,000 objects in our solar system I say that we do know enough (at this stage) about the objects in our solar system to catagorise the objects for scientific purposes.

My guess is that once we (human kind) study it up close and personal, we are likely to recatagorise it again but as something new!

Cheers

higginsdj · #10 16-04-2007, 02:32 PM

Quote:

Originally Posted by ving

we just do not know enough about our own system and other systems to be able to properly say yes it is or no it isnt. it was called a planet and so it should remain till we can more properly discover what else there is out there to compare it to.
thousands or even millions of textbooks are now wrong and the IAU could be found to be wrong due to thier lack of knowledge.
is a ball of gas really a planet?

I think thats the point of the re-catagorisaton..... We already have:

Terrestial Planets
Gas Giant Planets
Ice Giant Planets
Dwarf Planets
and the Old Minor Planets

Cheers

ving (David) · #11 16-04-2007, 02:33 PM

350,000... how many objects are there and what do we really know about them.
tis just the human ego that is stopping us from saying "we really just dont know!". we as a race are far too pround of the infantisimally small amount we know... or think we know about the universe around us.

higginsdj · #12 16-04-2007, 03:56 PM

Well for starters we know at least a rough orbit and size. For many we know their actual orbit, surface Taxonomy, actual size, albedo, rotation rate, shape and other characteristics such as moons etc. I guess it depends on what you think we need to know :-)

cahullian · #13 17-04-2007, 03:37 AM

I voted yes because I don't like to rock the boat.

Gazz

duncan · #14 17-04-2007, 10:30 AM

Hi all,
I voted no because it's been a part of what we termed our solar system for so long. It also has a proper orbit and moons of its own. I guess it comes down to a personal view,having said that where or when does it end?
Cheers

shredder · #15 17-04-2007, 02:42 PM

Hi All,

I voted with the no camp. Mostly for historical reasons, it was named as a planet, and accepted as a planet for many years. Now it gets demoted because someone picks up a blip much further out and says "what about me". We can hardly resolve Pluto, how much faith do we realy have in resolving the more distant bodies, and what are we going to do if we find oops they were more reflective and just looked bigger (or similar) ....

I mean what exactly is a dwarf planet... its just a crappy compromise... what will they do if they find a realy large body out there, call it an "outer planet" or a "slow planet" (due to the rotation period) or similar...

But that said I wont loose any sleep over it either way.

ving (David) · #16 17-04-2007, 04:18 PM

Quote:

Originally Posted by higginsdj

Well for starters we know at least a rough orbit and size...

rough being the operative word me thinks... so much of what we know falls under this word.

Dr Nick (Nick) · #17 17-04-2007, 05:45 PM

Simply, I think that if scientists had known what they were doing in the time of it's discovery, it would not have been a planet in the first place, but, since it was a planet for so long, I think many (non-astronomical) people are still going to consider it a planet.

higginsdj · #18 18-04-2007, 11:17 AM

Quote:

Originally Posted by ving

rough being the operative word me thinks... so much of what we know falls under this word.

'Rough' is a relative term. You'll need to look at the uncertainty parameter on each target. U is based on 'runoff' per decade from the predicted position. All numbered objects have a U <= 2. The following table from the MPC is in ArcSeconds per decade.

U - RUNOFF "

0 < 1.0
1 < 4.4
2 < 19.6
3 < 86.5
4 < 382
5 < 1692
6 < 7488
7 < 33121
8 < 146502
9 > 146502

There are some 'Lost' targets and many that are so new they are in need of follow-up to improve their orbits but on the whole you'll find U values are pretty low. MPC talks in terms of RMS for each position of under 1" being precise!

Cheers

ving (David) · #19 18-04-2007, 11:33 AM

eh?
i'll take your word for it... as the general public do when experts talk. right or wrong we take thier word for it.

leon · #20 18-04-2007, 01:09 PM

I don't agree with the decision.

Anyway how come this small group of people can just say, oh, I think we'll change that, or na, we don't like that idea, this would be better, It's a bit like, If it ain't broke, don't fix it.

Now that's scientific, isn't it....

Leon