Something else that's on my mind

[dianeduane]

Comments

[alexander.livejournal.com]

On my dorm hall we've taken to shouting "PLUTO PREVAILS" at each other.

Pluto will always be a planet in my heart.

[mizkit.livejournal.com]

Oooh, I might have to get one. Snif! Poor Pluto!

[anamin.livejournal.com]

Yeah, I'm seriously wondering about this one. . .

[tyleet1047.livejournal.com]

Amen!

[angoel.livejournal.com]

Given the choice of calling pluto a 'dwarf planet', and having all the other rocks similar to pluto becoming planets, I'm all for the 'dwarf planet' theory.

Because otherwise, the term 'planet' becomes meaningless.

[batyatoon]

It doesn't become meaningless in the slightest. It just becomes broader. I've got no problem with that.

[angoel.livejournal.com]

That's your descision. I, on the other hand, am of the belief that by the time we get to the stage of having several dozen planets in the solar system, then we'll need a term which defines the ones that we care about.

And I think that the term 'planets' for the ones we care about works, and 'dwarf planets' for the ones we don't care about works also.

Your milage may, of course, vary.

[xipuloxx.livejournal.com]

I agree with you, angoel. At the end of the day, Pluto doesn't care how we define it. But since it's clearly one of the Kuiper Belt objects, like "Xena", calling it a planet would mean we'd have to call them all planets, or at least all the larger ones. It's only been called a planet historically because it was originally thought to be bigger than it is, and because we didn't know it wasn't unique.

I think this is a very sensible decision.

[artela.livejournal.com]

Yup - eminently sensible decision - we can't go calling all large Kuiper Belt objects planets! And Pluto isn't even a solo Kuiper Belt object, it's actually twinned, it doesn't follow a "proper" orbit in line with the major planets, and keeping Pluto as a planet would've had the absurdity of having to also count Ceres and a while load of other vaguely round stuff planets as well.... we'd've had hundreds of the darned things :-)

[batyatoon]

And I think that the term 'planets' for the ones we care about works, and 'dwarf planets' for the ones we don't care about works also.

This, of course, begs the question of who is doing the caring.

It's not a real scientific way to decide nomenclature.

[replica.livejournal.com]

haha. awesome. I need to get that shirt.

[dduane.livejournal.com]

Click on it to order. :)

[replica.livejournal.com]

oh, I didn't even notice that. eheh. It'll be up for awhile, hopefully? *can't afford it just quite yet*

[great-eye.livejournal.com]

Oh, yeah! I like that!

[sdorn.livejournal.com]

That shirt shouts Dairine at me.

[dduane.livejournal.com]

It does, doesn't it? :)

[sdorn.livejournal.com]

Probably too late in the publication cycle to insert it somewhere in A Wizard of Mars...

No, don't answer. If it's not too late, the appearance should be a surprise.

[batyatoon]

Amen.

(Which I say only because I'm not sure how you would take it if I shouted "TESTIFY, SISTA!" instead.)

[dduane.livejournal.com]

Wouldn't mind it a bit.

[batyatoon]

Oh. All right then.

*clears throat*

TESTIFY, SISTA!

[madfilkentist]

I really don't care whether someone calls Pluto a planet or not, but I hate bad science. Pluto's closest approach to Neptune is 30 times the distance from the Earth to the Sun, and yet Pluto is said not to have "cleared its orbit." By that measure, Earth hasn't cleared its orbit of (at least) the Sun, Mercury, Venus, or Mars.

[syberghost.livejournal.com]

It hasn't cleared Charon out of its orbit yet.

[dd-b.livejournal.com]

I've always been skeptical of Pluto. This thing of coming in inside the orbit of Neptune periodically is simply not correct planetudinous behavior. And that orbital inclination! I mean, really!

I could have lived with adding Ceres and friends as planets and leaving Pluto; what I couldn't stand was having Charon promoted to planetary status. It looks like that's not going to happen, anyway.

Of course, given how Pluto and Neptune overlap, seems like neither one of them has actually cleared out its orbit....

[starcat-jewel.livejournal.com]

Actually, if you look at the situation in 3D rather than 2D, they don't "overlap" at all. The section of Pluto's orbit that is inside Neptune's is also well away from the plane of the ecliptic, so there would be no way for Neptune's gravity to interfere with Pluto's orbit (which is what "clearing out its orbit" means).

Of course, Earth's Moon also fails the most basic test for a satellite: its orbit is never concave away from the Sun! Technically, we inhabit a double-planet system very much like Pluto/Charon.

[batyatoon]

Of course, Earth's Moon also fails the most basic test for a satellite: its orbit is never concave away from the Sun!

I've heard that before and never quite understood it. Anyone know offhand if there's a page online that explains it? Preferably with diagrams?

[bellinghman.livejournal.com]

http://en.wikipedia.org/wiki/Double_planet

(What its orbit is never concave away from the Sun! means, I dunno.)

[duskwuff.livejournal.com]

If you held a piece of paper over the solar system and traced out the path of the Moon, it'd trace out a path that was always convex. Specifically, it'd be a sort of blobby shape, not the spirally thing you might expect.

[starcat-jewel.livejournal.com]

The Moon never "falls" away from the sun as it travels around the Earth. A true satellite would, at some point in its orbit, be moving in a path that was convex toward the Sun and concave toward the Earth.

[bellinghman.livejournal.com]

Not having traced out the cyclic, I can't actually tell. But I think I understand what you meant now.

However, I don't see why a 1 kg satellite of the Earth that happened to have the same period as the Moon does wouldn't follow pretty much the same path. Couldn't it have the same orbit?

[kengr]

There's another factor. As Asimov pointed out in one of his science essays decades back, if you work out the relative forces exerted on the moon by the earh and the sun, you discover that the sun is pulling 4 times harder than the earth is!

Sure, the same would apply to your 1 kg satellite. But its orbit would be *extremely* unstable due to the presence of the moon and the sun.

For that matter, it's next to impossibnle to have a stable long term orbit around the moon. At low altitudes, you've got all the mascons in the moon tugging in various directions. At higher altitudes, you've got the Earth and the sun pulling things out of shape.

[jeeperstseepers.livejournal.com]

I think it would be kind of awesome if it were somehow decided that Earth is not a planet. Oh, the identity crisis! Oh, the fun!

[batyatoon]

That's easy!

We just have to go with the Jovians' definition of "planet." By which definition our system has three-maybe-four planets, and a bunch of titchy little moonlike objects between us and the sun.

[jeeperstseepers.livejournal.com]

Sure, sounds good to me. I know practically nothing about all this--wrong area of science--so I'll just go with the flow. By the way, from your name and profile, looks like you and I may have a couple of things in common, and I'm currently finishing up my PhD at your alma mater where I was also an adjunct lecturer for three years.

[batyatoon]

Eh, I don't really know all that much about it either -- two undergraduate courses in astronomy plus reading hard SF and being generally curious.

And do tell. Which alma mater? I started my degree in one place and finished it in another, and ... come to think of it, I don't think I listed either of them in my userinfo.

[jeeperstseepers.livejournal.com]

I cheated. The stuff in your profile made me want to follow the link you have to your website, where you mentioned QC.

[batyatoon]

Ahhh. Well then!

Looking at your profile, I do believe you might be right.

[bellinghman.livejournal.com]

I thought it was obvious that Earth isn't a planet. A planet is one of those stars in the sky that wanders against the celestial bowl. The Earth is patently not up in the sky.

[posicat.livejournal.com]

Poor pluto, now it's going to get non-stop enlargement spam mail.

[badger.livejournal.com]

I liked this response I saw over the weekend:

http://photos1.blogger.com/blogger/6851/680/1600/261299lRTQ_w.jpg

[kengr]

"Access denied"

[trdsf.livejournal.com]

*lol!* I love it, and I've been in the 'demote Pluto' camp for years!

Speaking as an amateur astronomer: the only thing I was interested in was a good, solid definition. It made less difference to me whether Pluto was cut in or cut out than that they actually drew a line that gave a clear-cut way to call something a planet or not. I expect this definition will be modified as we discover more exoplanets that stretch our definition. They're going to need to add something on the top end to divide between the largest gas giants and the smallest brown dwarfs. There should be a definition for a double planet (two worlds that would individually make the cut, mutually orbiting a barycenter that lies between the worlds, not within either one, say).

[starkruzr.livejournal.com]

It astonishes me that there are actually people who REALLY CARE whether or not astronomers deem it a planet. And I love space, astronomy and space exploration!

[trdsf.livejournal.com]

It pleases me that people care--that means there's hope for science among the greater populace, that scientists and science do matter, and that's the sort of mindset we need to get more money sent to NASA.

It astonishes me that there are people who care more about the outcome (that Pluto is/isn't a planet) in the process (that we have a good, scientific definition that gives unambiguous results).

Ceres

[psycho-machia.livejournal.com]

what about poor Ceres it was a planet then in the 19th century was downgraded, then recently upgraded along with Xena and now down graded again.

Not to mention Chiron!