Neil deGrasse Tyson and Michael Brown - Is Pluto a planet?

[Kuren420]

Neil was great in this video but the video kind of sucked. Go Neil!

[rajuncajunqueen]

i love neil i love pluto an i really loved that last arrow lmao thanks

[williamcardno]

You say "let's not forget the word 'Theory'" at the end though, when "theory" has never had more than one use in any context:

A model or framework that makes sense of the evidence/ideas provided.

[ReadMyCommentBitch]

"everyone else just has to grow old and die"

[albinoman13bt]

Sorry, Tyson is right, Pluto isn't a planet. It's a big comet. It's over half ice, just like a comet. It has a highly elliptical, tilted orbit, just like a comet. It resides in the Oort Cloud, again just like a comet. There are bigger asteroids and moons in the solar system. It's so small, that because of it's "moon", Charon, the orbital axis is outside Pluto, unlike the planets. Remember, we did had 13 planets at one point.

[npdarren]

I'd say "Bah, just let people call it what they want to call it", but I know better. So long as there are some people who genuinely believe Pluto is a planet, and people who genuinely believe it is not, there will be conflict, even if we somehow segregate the definition into different categories.

My opinion; "planet"is a word, and the meanings of words are dictated by the opinions of people. The word "gay", for example, has several connotations...

[npdarren]

...but serves as a general term to describe something. We use "planet" to describe things in the same manner. Whether we call it a planet or a spaghetti monster, or whatever, Pluto will still be Pluto. All words are good for is allowing us to form a schema in which we can visualize something by its description.

[SuperMagnetizer]

Let's just call midgets "minor people" from now on. After all, their size disqualifies them from being real people.

Planet Pluto has 3 of its own moons.

[theinquisitor]

So do you want to call Sedna, Ceres and Eris planets too? As well as dozens or perhaps hundreds of others? If you include Pluto and not those, then it becomes an absurdly arbitrary category.

If we had known Pluto's size when it was first discovered, it would never have been called a planet.

[SuperMagnetizer]

Here is my recommendation. All bodies orbiting the Sun that are spheroidal in shape should be called planets. These should be further subdivided into three main categories: terrestrial planets, gas giant planets, and planetoids. Asteroids would not be spheroidally shaped.

Sedna, Ceres, Eris, and Pluto should be known as planetoids, as distinct from asteroids.

[theinquisitor]

The term planetoid is already in use as a broad category to describe anything from rocks a few tens of metres across to objects like Ceres. The term dwarf planet is used to describe bodies like Ceres, Sedna, Pluto, etc.

Also, objects of that kind that are trans-Neptunian are called Plutoids.

This difficultly arises because we're trying to put discrete barriers between objects that lie on a continuum. A planetoid by any other name would be just as interesting.

[SuperMagnetizer]

It's interesting you bring up the fact that these object all lie on a continuum. In fact the spectrum would extend from micro-meteoroids up through the most massive stars and even to black holes. The delineations would therefore be quite arbitrary. The problem is we lack the vocabulary to describe the bewildering array of objects the Universe has set before us. This brings to mind the Eskimos, who have dozens of different names for snow. But I personally loathe the term Plutoid.

[theinquisitor]

Indeed, it is mostly arbitrary. Although there are a few cases where there is a distinctive line between some objects.

Such as a neutron star. There's no object that falls between a neutron star and a normal star, unless you count the brief moments of transition between the two. And there's nothing between a neutron star and a black hole.

The tipping point where gravity overcomes the nuclear forces makes this limit very definite, giving us some discrete categories.

[SuperMagnetizer]

Good points, thanks! But that last arrow into Pluto hurt.

[puncheex]

@SuperMagnetizer: Ah, but some of the planetoids are. Pallas, Ceres, Juno and Vesta are all spherical. The actual current definition is:

"A 'planet' is a celestial body that: (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighbourhood around its orbit."

You were close, though.

[puncheex]

@SuperMagnetizer: Yeah, and it orbits in a highly inclined, highly elliptical orbit on the inner edge of the Kuiper belt.

You know, biology has this same problem with words. When I was a kid, we know what birds were, what dinosaurs and apes and monkeys and humans were. Now, birds are dinosaurs, dinosaurs are reptiles, humans are apes, apes are monkeys (and therefore we are monkeys, as well as primates, tetrapods, amniotes, chordates and bilateria). So what's in a name?

[fher004]

Pluto: MAKE ME A PLANET AGAIN YOU ASSHOLES

[theinquisitor]

Sedna: Me too! I'm almost as big.

Haumea: And me, I'm more than half the mass!

Ceres: Why not me? I used to be called a planet!

Eris: I'm even bigger than Pluto, make ME a planet!

You see the problem. A consistent classification would require the number of planets to go up potentially into the hundreds. Pluto is 0.002 earth masses. It's a tiny little rock that no-one would have classified as a planet if we'd known how small it was when it was discovered. Why call it a planet and not Eris?

[darfunkelidas]

I disagree, it only creates more confusion. People should start using the word hypothesis or hypothtetical instead of theory/theoretical. And I do think we should call it Luna. Think about all the problems the misuse of the word theory has caused on continues to cause to this day.

[theinquisitor]

The words hypothesis and theory have distinct meanings. A hypothesis is essentially an unverified theory. Replacing uses of the word theory with hypothesis will create the impression that we have lost confidence in such theories. I don't think misusing the word hypothesis will counter the effect of misuse of the word theory.

I think the solution is to educate people about what these words mean in a scientific context and make it clear that they are not the same as the colloquial context.

[darfunkelidas]

No, I meant it the other way around, tell people to colloquialy replace their use of the word theory by the word hypothesis, which is what they really mean.

[darfunkelidas]

And yes, the real theories should still be called theories (example the theory of evolution) I mean that they should use hypothesis when they say something like "I have a theory" which is not the right use of the word theory.

[theinquisitor]

Ah I misunderstood. Yeah that does seem like a more appropriate use of language. I do get annoyed at the constant misuse of the word theory in science fiction for example.

But I have my doubts about whether it's realistic to expect people to change their casual use of that word. I think the best we can hope for is to explain that scientists mean something different when they say theory than they do. I would like to see scientists in popular fiction at least use the terminology correctly.

[theinquisitor]

Also, I'm not entirely sure that the scientific definition of the word should take precedence in non-scientific arenas.

I had a brief look at the etymology of the word and it seems that it did arise before the modern scientific conception of a theory as we understand it. So it doesn't seem right for scientists to claim "ownership" of the word and dictate how others use it.

When the subject isn't science, I don't have a problem with the non-science definition of the word.

[DrakhIM]

neal should go down in history as- "THE JERK THAT KILLED PLUTO!!!"

[theinquisitor]

It's still there. In fact, it's gone from being defined as the smallest planet, to the first known object in a whole new class of objects, the plutoids. It's the king of the plutoids. It's got a whole category of objects named after it. Isn't that better than being the smallest planet?

[johnsmdm]

kids throughout the world are wailing and crying because of Neil..Pluto we'll save you..we are organizing a protest of thousands and march against the provost..

[theinquisitor]

If you want to call Pluto a planet, then you have to call a lot of other objects that are of similar characteristics planets too. That would raise the planet could into the hundreds.

The purpose of a category is to efficiently communicate information. If the category of planet is so broad that it can include objects that would be comets if they were close to the sun, and gas giants, then the category is pointless because it doesn't provide you with much more than the word "object" does.

[paperplanessss]

omg that lamp cracks me up. gotta love that neil !

[bodenga]

i say they prove australia is really an island next

[theinquisitor]

Depends on your definition. They're all just labels that we use for conveninece of not having to describe the object again. The problem is that when pluto was first found it was thought to be much larger. If it had been known how small it was when it was found, it wouldn't have been called a planet at all. If Pluto is a planet, then why not Ceres, a spherical body in the asteroid belt.

[BlueberryhillCB]

our favorite planet is Mars and Pluto

[ChimeraMouse]

"FUCKING PLANET!"-excellent. Isn't Saturn everybody's favorite?

[theinquisitor]

Yeah you've got to love Saturn. It's almost a mini solar system with it's numerous moons and rings. Pluto whatever it is, is rather uninteresting by comparison, and far enough out to be not worth that much attention. The moons of Saturn are more interesting.

[RobRock07]

good vid

[near2earth]

Neil deGrasse Tyson took wood shop? And got an "A" (on at least one project)! I'm swooning.

[Elaina43]

nah - Tyson's proposal ain't gonna never fly... ;‹D

[nonadherent]

LOL, "too sciencey."

[kurtilein3]

thats incredibly funny ^^

well, some words should be protected, like the word science. people like to claim that something is science while in reality it has nothing to do with science, and i oppose that, no matter who does it and why.

in my oppinion pluto is not a planet, its a rock.

[RobAlone]

I hear ya. Vernacular.

A friend and I were discussing Pluto's demotion a couple of weeks back. We came up with this:

Planet=wanderer. Therefore any thing larger and with greater mean radial velocity relative to the Earth, than Pluto; might be a decent enough description of a 'planet'. It would rule out Xena (or whatever it's called).