Pluto relegated to the underworld

[mcgillianaire]

The International Astronomical Union has redefined our solar system by declaring Pluto to be a dwarf planet. As a result, there are now only 8 true planets & 3 newly-created dwarf planets.

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Comments

[3neonangels.livejournal.com]

aww i know... kinda made me sad. btw, you know how i have the bbc ticker? so it keeps scrolling across saying "inzaman to get hearing date from the icc" which to me means international criminal court! i know it's the international cricket something or other but i feel they need a new acronym.

[mcgillianaire.livejournal.com]

the international criminal court should change their name. the international cricket council has existed with that acronym for 97 years vs the 4 years for the criminal court. :)

[pappubahry.livejournal.com]

Sort of, as I'm sure you're aware. Ninety-seven years ago, it was the Imperial Cricket Conference, then in 1965 it became the International Cricket Conference, and only became the International Cricket Council in 1989, still 13 years before the birth of the criminal ICC.

[caffeinefables.livejournal.com]

Random note; your user picture really reminds me about the cover of The Alchemist. At least the cover on my copy. Ever read it?

[mcgillianaire.livejournal.com]

Interesting! I have actually read that book... this summer infact. The userpic however is of an Omani bedouin :)

[caffeinefables.livejournal.com]

Someone native in Saudia-Arabia, right?

[elodie21.livejournal.com]

It really feels strange that Pluto no longer qualifies as a planet...so many books will have to be re-written and models of our solar system changed.

[swimanubis.livejournal.com]

its a ploy to get people to buy 'new and improved' textbooks

[elodie21.livejournal.com]

Hahaha thats one way of looking at it!

[pappubahry.livejournal.com]

About time.

Though one of the astro PhD students thinks that Pluto should have stayed a planet, since you need it to explain perturbations in Neptune's orbit.

[mcgillianaire.livejournal.com]

Perturbations?

[pappubahry.livejournal.com]

Imagine the universe is just the sun and Neptune. Essentially, Neptune orbits the sun in a slightly elliptical orbit. Now put the other planets in there. The gravity of the other planets perturb Neptune's orbit.

[gpaciga.livejournal.com]

The fact that something perturb's a planet's orbit does not mean that that something should also be a planet. Everything in space perturbs everything else.

[pappubahry.livejournal.com]

I agree that Pluto shouldn't be a planet, but I'll trust my astro friend when he says how influential various objects are in planetary orbits.

[gpaciga.livejournal.com]

I'm not saying it's not influential, I'm just saying that that's not good criteria for being a planet. I'm in physics as well, by the way.

[thangkas.livejournal.com]

There should actually be more "dwarf planets", or they just need to unclassify that and call them planetoids/TNOs as they were before, otherwise the discussion turns to distance from the sun and size/shape. I mean, Ceres? Really? And Charon!?!? That's a satellite of Pluto! So does that mean Pluto is a binary dwarf planet?!

[pappubahry.livejournal.com]

And Charon!?!? That's a satellite of Pluto! So does that mean Pluto is a binary dwarf planet?!
I'm not sure what the current status is, but I think it quite likely that Pluto-Charon will be considered a binary dwarf-planet system. The reason for this is that their common centre of mass is outside both planets (which is because Charon has roughly half the mass of its 'parent planet', unlike all the other moons).

[thangkas.livejournal.com]

Which also points even more so to the impression that it should not be called a planet. Mind you the current definition of planet as it stands now discounts Charon on this basis (as well as many others) as well.

[mcgillianaire.livejournal.com]

What does TNO stand for?

[pappubahry.livejournal.com]

Trans-Neptunian object.

[thangkas.livejournal.com]

Trans Neptunian Object. Another name for KBO (Kuiper Belt Object)

[gpaciga.livejournal.com]

There certaintly will be many more dwarf planets -- there are at least twelve more on a waiting list already. That's why they wanted to make the distinction between the classical planets and the more common dwarfs.