Goodbye Pluto

[cob]

It's official guys, Pluto is now a "trans-Neptunian object" or "dwarf planet".

From the proceedings of the IAU:

RESOLUTIONS

Resolution 5A is the principal definition for the IAU usage of "planet" and related terms.

Resolution 6A creates for IAU usage a new class of objects, for which Pluto is the prototype. The IAU will set up a process to name these objects.

IAU Resolution: Definition of a "Planet" in the Solar System Contemporary observations are changing our understanding of planetary systems, and it is important that our nomenclature for objects reflect our current understanding. This applies, in particular, to the designation "planets". The word "planet" originally described "wanderers" that were known only as moving lights in the sky. Recent discoveries lead us to create a new definition, which we can make using currently available scientific information.

RESOLUTION 5A

The IAU therefore resolves that "planets" and other bodies in our Solar System be defined into three distinct categories in the following way:

(1) A "planet"1 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.

(2) A "dwarf 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) shape2 , (c) has not cleared the neighbourhood around its orbit, and (d) is not a satellite.

(3) All other objects3 except satellites orbiting the Sun shall be referred to collectively as "Small Solar-System Bodies".

IAU Resolution: Pluto

RESOLUTION 6A

The IAU further resolves:

Pluto is a "dwarf planet" by the above definition and is recognized as the prototype of a new category of trans-Neptunian objects.

[Evan G]

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[wendy]

wow i can't wait to have kids and grandkids one day and have to explain to them that I am soooo old that we had more planets when i was younger.

[Evan G]

wow i can't wait to have kids and grandkids one day and have to explain to them that I am soooo old that we had more planets when i was younger.

You gave me a chuckle, nice!

If people would stop debating we stop loosing planets!

[Realms]

To bad on the demotion. We just launched the New Horizions probe back in January to study Pluto and the Kuiper Belt objects. Man that was an amazing launch. The probe will pass Pluto in 2015. Its the fastest thing launched so far. It will pick up a gravity assist from Jupiter to increase its speed even more. If you would like more info or if your curious of where the probe currently is, visit this link

http://pluto.jhuapl.edu/index.php

[Teresa]

Now that's just Goofy.

[Evan G]

Now that's just Goofy.

Oh man , it is doggy dog world!

[Teresa]

I can see it now in every astronomy text: "The Pluto formerly known as planet."

[Evan G]

Teresa wrote:

I can see it now in every astronomy text: "The Pluto formerly known as planet."

I hope they don't just give it a Zodiac sign. The planet formerly known as:

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[hewhocaves]

wow i can't wait to have kids and grandkids one day and have to explain to them that I am soooo old that we had more planets when i was younger.

this isn't the first time this happened.

Ceres was initially called a planet, then demoted to asteroid status.

I'm not upset by the change, but the rationalle they gave left a lot to be desired.

John

[wendy]

we could just boycott it and keep it as a planet, just like some americans (most all i think) don't use metric when they tried to force it on me as a kid, and how like some states don't do daylight savings time

[graveleye]

why did Pluto have to walk on 4 legs, when Goofy walked on 2? They're both dogs arent they?

[hewhocaves]

we could just boycott it and keep it as a planet, just like some americans (most all i think) don't use metric when they tried to force it on me as a kid, and how like some states don't do daylight savings time

yes, or like how some americans want to boycott science in favor of creationism.

[hydrology_joe]

So what is the mnemonic to remember the nine...er I mean 8 planets?

Growing up it was "My Very Educated Mother Just Sent Us Nine Pizzas"
(Others are available from "Wikipedia" when there was still 9 planets...)

[Grandpa Caver]

why did Pluto have to walk on 4 legs, when Goofy walked on 2? They're both dogs arent they?

Goofy had sufficient mass for his self gravity to overcome rigid body forces so that he assumed a vertical equalibrium.