12 planets in the Solar System will be official count on 24th of August

[Stylesrj]

Ridiculous indeed.
Those should just be dumped into a new solar system, like I said, they should be Perfectionoids and be part of the Perf Solar System


Perfection, unless those robots we send are giant and cause death, then I don't see the point. What's the use of Space Pirates without the GDRs?

 

[Tee Kay]

Ridiculous indeed.
Those should just be dumped into a new solar system, like I said, they should be Perfectionoids and be part of the Perf Solar System

1) yes the new IAU definition is ridiculous. We agreed on that.
2) No we do not need another Solar System. You can't divide a star system in two just because there's too many objects to count. KBOs, asteriods, trojans, centaurs, comets and traditional planets all orbits the sun.

 

[ainwood]

Moderator Action: This looks suspiciously like spam.

Stop the user-specific discussions, and keep the discussion reasonable, and on-topic. FYI, breasts are not "on topic".

 

[Stylesrj]

Sorry about that, we were just joking around.

Too many objects to care about for our solar system! Why bother having them when they're going to cause problems later on. Those astronomers should be doing something useful besides wasting money on theories and looking at balls of rock in space and deciding if they are part of our solar system or not. Millions of dollars are going down the drain just so we know how many fricken planets we have orbiting our sun! Millions that could've been spent elsewhere, like to pay the huge cheques for the cancer-curing doctors or even in the government's coffers

 

[mdwh]

Before we go on, I would like to welcome these solar system bodies, soon to become planet #13-24 under the new IAU definition. (diagram to scale)

Yeah, I was wondering about Sedna and the others...

Compare the size of these rocks to Earth and you'll see how ridiculous the new IAU definition is. I mean, Vesta, for instance, is smaller than Texas.

The question is I think, should size be a factor?

A lot of people here have said that size can't be a factor as it's too arbitrary - but have then tried to come up with various other conditions, and it seems to me that these are nonetheless cunning ways to get rid of these new small bodies, without directly referencing their size. The problem with this is that even if it happens to work for now, it may not work for other systems - e.g., if we have a definition which references "the only body in its orbit" or talks about the angle of the plane - what if we find a bloody great body or even gas giant orbiting at an odd angle?

Also "the only body in its orbit" must surely ultimately include a reference to size - otherwise Earth would be discounted, as I believe there other bodies (3753 Cruithne) in the same orbit, but not orbiting the Earth. Presumably we would discount this by the tiny size of such bodies- but there you are, a reference to size.

I would say that if size is to be a factor, then we should just admit, and make an arbitrary limit (which means either getting rid of Pluto, or including Xena). Possible we could use another term for spherical objects smaller than that.

Alternatively, I'm happy with this new definition. Yes, they may be small, but my perception (and I think, people's in general) of an asteroid is a lumpy piece of rock, but that diagram shows just how spherical these objects are. If they weren't labelled, I think many people would say they look like planets (or moons, though obviously they can't be moons), not asteroids.

How small is small? And consider how small Earth is to the gas giants...

 

[Perfection]

I think my definition scheme works great it maintianing the 8 planets as well as providing guidelines for extrasolars without requiring an arbitrary size cutoff:
http://forums.civfanatics.com/showpost.php?p=4220429&postcount=24

 

[mdwh]

I think my definition scheme works great it maintianing the 8 planets as well as providing guidelines for extrasolars without requiring an arbitrary size cutoff:
http://forums.civfanatics.com/showpost.php?p=4220429&postcount=24

Yeah that's a good definition I think (though I'd say this is still an arbitrary limit on how much material forms the planet, but going by mass rather than volume/diameter).

I feel all this is only an issue because "How many planets are there" is such a part of popular culture, and something everyone knows. No one cares about the exact definition of a mountain, because no one cares how many mountains there are. Maybe when we have 200 planets, it'll be the same - people will know the names of the most well known ones, but there won't be some special category for the these ones.

 

[Perfection]

Yeah that's a good definition I think (though I'd say this is still an arbitrary limit on how much material forms the planet, but going by mass rather than volume/diameter).

No, becuase it's based on qualitative behavior. What do all the 9 Planets but Pluto have in common? They're all masters of thier orbital domain. They herd small bodies from one place to another, they force them into belts and fields where there are no planets or into thier lagrange points. KBOs don't do this, neither to Asteroids.

This I think is the key concept around which the definition should be based.

 

[JohnRM]

Jesus, its a bunch of rock, ice, and crap orbiting the Sun. Who cares what you call it?

 

[Perfection]

Jesus, its a bunch of rock, ice, and crap orbiting the Sun. Who cares what you call it?

Lots of people, apparently. It's a fun debate for science wonks, given its relative ease of understanding, common knowledge impact, and how one can put forth thier own pet definition.

 

[ThePhysicist]

Oh great. Here I am thinking they are finally going to be sensible and strip Pluto of it's undeserved title- and then while I'm not paying attention they change their minds and head the other direction.


I (also) agree with Perfection's scheme. It works, and does not rely on arbitrary numbers.

 

[Perfection]

Here's the general scheme of planets to come according to Brown if this doohicky passes

 

[{|}$~\]

This decision won't be carved in stone. If it gets too confusing, the IAU can change it again.

 

[Perfection]

This decision won't be carved in stone. If it gets too confusing, the IAU can change it again.

I'd rather not see it happen.

 

[zjl56]

I would hope that they put a size restriction on a planet. Such as a star orbiting annother star.

 

[Bozo Erectus]

Those jerks Now every fifty years a new generation of 'boffins' will take a vote on how many planets we have?

 

[Winner]

It is the most idiotic definition of a planet I've ever seen. Scientific? Maybe, but it completely ignore the historical dimension of the term "planet" and if it passes, it will confuse the public as never before.

Let's finally define planet as a body orbiting star, of roughly spherical shape and orbiting the star on not very eccentric orbit more or less on the ecliptic plane.

We Czechs are used to that only bad things come out from Prague, but I wouldn't have thought it will expand its sphere of idiocy beyond our borders...

EDIT:

This is what I mean - all solsys planets' orbits are rougly on the same plane. Of course with exception of Pluto, which is not a planet. Also in other solar systems, planet usually orbit their parent star on one plane. This is IMHO the best defining characteristic of a planet.

 

[Pontiuth Pilate]

The major features of our solar system are 8 planets and an asteroid belt.

I wonder how many of these KBOs could be spotted by an astronomer with a telescope planted on Alpha Centauri.

 

[Perfection]

Let's finally define planet as a body orbiting star, of roughly spherical shape and orbiting the star on not very eccentric orbit more or less on the ecliptic plane.

That's not a good definition. Ceres and probobly a couple other asteroids would get in, and Quaoar and some other KBOs might slip by too. Also eccentric extra-solar Jovians would be discounted. These are obviously unnacceptable If you look back a few posts you'll see my scheme which I contend is probobly the most true to common and historical perception as well as having scientific meaning.

The major features of our solar system are 8 planets and an asteroid belt.

The Kuiper Belt is much much larger then the asteroid belt. Also, you left out Mr. Sun!

I wonder how many of these KBOs could be spotted by an astronomer with a telescope planted on Alpha Centauri.

I'd be surprised if they could see Jupiter or Saturn. You'd need one crazy-ass telescope to even do that!

 

[Winner]

That's not a good definition. Ceres and probobly a couple other asteroids would get in, and Quaoar and some other KBOs might slip by too. Also eccentric extra-solar Jovians would be discounted. These are obviously unnacceptable If you look back a few posts you'll see my scheme which I contend is probobly the most true to common and historical perception as well as having scientific meaning.

I'll read this thread through ASAP, but on a side note: I don't think that the orbital eccentricity should be the most important criterion, but I'd keep it when talking about our own solar system. I mean that the term planet should have slightly different meaning when talking about our solar system, simply in order to appease the history, culture and finally, the astronomy.