The Solar System is a Mess

What a crock! By that standard of reasoning, we might as well stop classifying galaxies because, after all, who cares if a galaxy is a galaxy. You want to identify and name every object in the asteroid belt just because it orbits the sun too? Be my guest, and let my great-great-grandkids know when you're finished too. And while we're at it, let's stop classifying diseases with names like cancer, aids, etc...I mean if you're ill, you're ill, right? Geology? What a waste. A rock is a rock is a rock.

If the US media wants to keep "dumbing down" the information it broadcasts, thats a shame but its there thing - and thank God we still have BBC America. But science is about understanding, which also means questioning and redefining basic beliefs, like whether or not the earth revolves around the sun. And while our media establishments are doing everything possible to boost ratings by appealing its programming IQ to the lowest common denominator, its the chinese who are graduating from our universities with science, math, and engineering degrees, in record numbers, and taking that knowledge back to China with them.

Now THAT's something our grand-grand-kids will have to deal with in their time. People like this guy should be barred from working in broadcasting.

All these "scientific" definitions, if taken as precise descriptions would knock most of not all planets off the planet list.

If a planet must be perfectly round and smooth, then we have zero planets, since none of the planets are perfectly smooth or round. Earth for instance, has mountains and valleys, while all planets, due to rotation, have a longer equatorial diameter than a polar diameter.

If condition 3, clearing it's orbit, is used in the strictest sense, then we may have two planets, Mercury and Venus. Jupiter has objects at trojan points in it's orbit than haven't been cleared. Even Earth has objects at it's trojan points plus hundreds of near earth objects that cross or approach it's orbit. The same applies to planets further out too. Mercury and Venus, due to their proximity to the Sun are the only objects that may not have any other objects in their orbit, including moons. Also, any moons have not been cleared from their orbits, so any planet with one or more moons would also be disqualified. Do we really want to be this precise? In fact, there are several moons larger than one or more planets. Mercury is larger than Pluto but smaller than Triton (a moon of Saturn). If Triton is not a moon and Mercury is smaller than Triton, then wouldn't that mean that Mercury isn't a planet? Also, since Neptune and Pluto's orbits cross, they haven't cleared their orbits and knock each other off the list.

I suggest the only valid qualification to being a planet is that gravity conforms them to a roughly spherical shape and that they orbit a star. Ceres is the only asteroid that fits this qualification, while several objects in the Kuiper Cloud, including Pluto, Charon, and Eros fit this criteria. I am fine with double planet systems and suggest that Earth-Moon could even be considered one.

Having to memorize eight planets is hard enough for many children. The thirteen listed planets in this article is just the tip of the iceberg.

There are many plutoids in the solar system that have yet to be given a regular named or to be discovered. There are probably thousands of them beyond the orbit of Pluto.

I would hate to be a school kid in the future where you have to name all five thousand planets of the solar system. I like the current method of planet labeling much better.

Saturn and Jupiter, the two huge gas planets in the center of our solar system, have been described as "failed suns", because even though they are huge gas balls, they have failed to ignite.
If we are turning our noses up at a body in orbit because it is mostly ice, are Saturn and Jupiter truely planets?

Ned
I have another question on the Pluto-Charon system. Does anyone know if their ordits are stable, expanding or deteriorating?

Jock5908: Pluto is essentially a big lump of rock and ice.

That's debatable among scientists and the nons. Pluto has an atmosphere, a surface, seasonal variations, and an orbit around the sun. I think it also rotates on an axis, if I'm not mistaken. As Tom points out, only Mercury and Venus have no objects within their obits, which would make the majority of the planets not conform the IAU criteria of having a cleared orbital path. When Pluto is reduced to a lump of rock and ice, it may as well be classified as an asteroid. I'm not opposed to creating classification systems, but am if they're circumscribed and create confusion.

Note from Ned Potter--

Quietman, to the best of my knowledge, the Pluto-Charon system is relatively stable. Pluto and Charon appear to stabilize each other -- each with the same side facing the other, much as we always see the same side of our moon, give or take a little libration.

One last thought from me: This is not about the number of planets schoolchildren ought to have to memorize. This is about how science ought to work. How ought it to make sense of things -- some of which are a lot less benign than this question of categorizing celestial bodies?

Thanks Ned, interesting information, also interesting comment on how science should work, making sense of the things around us. My thoughts exactly.

kat
Paleontology suffers from similar problems. We have the older standards of Taxonomy and the newer concept of cladistics. I use both in my database and have to give sort priority to one or the other (I chose taxon). It is very confusing and there seems to be little agreement. This talk of dwarf planets is much like talking about gas giants, OK for a description but not for nomenclature.

Quietman, I prefer the geophysical descriptions of planets to the nomenclature because it's familiar. But that aside, Sykes likens the IAU classification system as "facts to be learned from authority." It seems arguable that a cleared orbiting space for planetary status can be applied consistently to this solar system, let alone another one. It could be that there's a sphere orbiting a very distant star with classical planetary attributes, with even H2O and green stuff, but without a cleared orbital space. Which brings to me this question: Are cleared orbital paths a necessity in planetary evolution? I would think there are plenty of uncleared orbital paths out there since I've been told it all began with a big bang.

kat
No argument.

Nature is perfect. Man is not. School science is not the final truth and never will be.

What about the T.V., the apple, and the book that orbited "Peter Griffen's" fat stomach wouldn't they be called planets too? From "Family Guy".