8 planets it is then

[mojo (Terry)]

"Astronomers meeting in the Czech capital have voted to strip Pluto of its status as a planet.... Astronomers rejected a proposal that would have retained Pluto as a planet and brought three other objects into the cosmic club."
http://news.bbc.co.uk/2/hi/science/nature/5282440.stm

Which will need a rider added to the phrase I learnt in primary school... My Very Energetic Mother Jumped Somewhere Up Near except Pluto.

[ballaratdragons (Ken)]

Thanks Terry,

Not good news mate!

Just in case some say "that's only what the BBC News says" here is the link to the actual Resolution results on the actual IAU site (International Astronomical Union). Scroll to the bottom for resolution 5a & 6a.

http://www.iau2006.org/mirror/www.ia...603/index.html

[Sonia]

Pluto was automatically disqualified because its oblong orbit overlaps with Neptune's. It will now join a new category of "dwarf planets".

What does it matter? It still orbits the sun!

So what happened to this?
http://news.bbc.co.uk/1/hi/sci/tech/4795755.stm

[Sonia]

http://www.space.com/scienceastronom...efinition.html

[glenc (Glen)]

It will be much easier to see all the planets now.
I have seen Pluto a few times and it was hard to find.
No need to tick it off now there are only 8.

[spacezebra (Petra)]

Hi Sonia

I agree, it still orbits the sun! (the more the merrier)

Cheers Petra

Originally Posted by Sonia

Pluto was automatically disqualified because its oblong orbit overlaps with Neptune's. It will now join a new category of "dwarf planets".

What does it matter? It still orbits the sun!

So what happened to this?
http://news.bbc.co.uk/1/hi/sci/tech/4795755.stm

[cometcatcher (Kevin)]

It's the end of the worlds as we know it!

I can hear Clyde Tombaugh turning in his grave. They never had the guts to do it when he was alive.

I never did see it when it was a planet. Oh well too late now.

[Rodstar (Rod)]

This whole debate leaves me a little cold. We are only talking about labels and pigeon holes.

[[1ponders] (Paul)]

Thank heavens the IAU has finally come to it's senses, or rather those voting have. What a ridiculous set of naming proposals, determining a planet simply on it's shape. Bah.

[acropolite (Phil)]

I don't agree, after all pluto IMO is more a planet than say Jupiter or Saturn. We could stand on earth and the other rocky planets but not on the gas giants?? Really pluto has more charactersitics in common with earth as a planet than any of the jovian planets; to simply characterise a planet by size is short sighted.

[spacezebra (Petra)]

Totally agree, with your analysis of the situation.

What are they going to do with the "New Horizons" mission - turn around and come home now that Pluto is no longer a "major" planet.

Cheers Petra

Originally Posted by acropolite

I don't agree, after all pluto IMO is more a planet than say Jupiter or Saturn. We could stand on earth and the other rocky planets but not on the gas giants?? Really pluto has more charactersitics in common with earth as a planet than any of the jovian planets; to simply characterise a planet by size is short sighted.

[iceman (Mike)]

heh, good point Petra.

[hogly52 (Graeme)]

I can handle the decision of the IAU, it at least has established a standard and definition for future discoveries. But I find it annoying that the ABC online news had to include the views of an astrologer into its reporting of a science activity.

Cheers,

Graeme

[iceman (Mike)]

oh gawd I can imagine the astrologers are up in arms!

I agree though, that's very bad reporting by ABC.

[xelasnave]

Has anyone considered the impact on astrology?
alex

[anthony2302749]

I hear the new this morning, I suppose we now have to change the way we discuss Pluto. We will have to develop a completely new vocab to describe this object; words such as Minute, Tiny, Diminutive, Miniature, Petite, Undersize, Planetesimal and Dwarf all which are very apt. My favourite at the moment is “Diametrically challenged” it avoids the problem of being political incorrect.

[ThunderChild (Chris)]

History shows that every time we think we understand our universe or even our solar system, some new discovery comes up which makes us completely rethink everything, because we were previously being a little simplistic or narrow. I think there are shades of that here - we've looked for a definition to include the classical 8 planets and leaves the others out. Pluto was always controversial.

Several problem appear here ;
(1) "Clear the neighbourhood around it's orbit". How vague is that? How far is one's neighbourhood? And how large do surrouding objects need to be before that neighbourhood is deemed "unclear"? Asteroids? Boulders? Pebbles? A few specks of dust?
I'm also assuming that things in orbit of the planet itself (eg moons, rings) are being excluded from being cleared since they are trapped by the planet itself.

Does this mean that if some event happened which brought some clutter into Earth's path of orbit that Earth would be demoted from planet status?

(2) "has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape" - I read this to mean that a round rock the size of my fist will be a planet if it's orbit is all alone.

Different materials require different pressures to bring them into a round shape. A small blob of water will very quickly form into a sphere. If it's "neighbourhood is clear", then it's a planet.

I think I'm missing some key pieces of knowledge about what these rules mean. Because it's all too easy to think up dozens of scenarios which would appear to break the definition.

I'm left a little unsatisfied by all this. While I completely bow to the superior astromonical knowledge of those concerned, on the surface this appears to be an extremely vague definition which has the hallmarks of needing to be updated in the future when something new forces us to confront the narrowness of our definition. Perhaps not in our solar system, but sometime we are going to start getting more and detail about other solar systems. I am convinced that our understanding is going to be completely blown apart as we learn more and more.

[Omaroo (Chris Malikoff)]

http://www.news.com.au/story/0,23599,20246532-2,00.html

The Australian, today.

What's going to happen to the good old "Pluto Pup"?

[Gargoyle_Steve (Steve)]

I find it incredible that the IAU sets up a comittee specifically to make a recommendation as to what should, and what should not, be considered a planet, the comittee drafts a set of guidelines, the IAU votes, and rejects the recommendations and actually goes in the opposite direction.

These guys act like politicians, not astronomers. Whether you agree or disagree with the final decision (I disagree, for what it's worth) the new rules still seem rather non-specific, and I'm sure the debate over this will rage for years to come.

When at school I learned the order of the planets by the mnemonic
"Most Volcanoes Erupt Mulberry Jam Sandwiches Under Normal Pressure"

I posted this back in March on these forums, but I'll post it here again.

With the official removal of Pluto as a planet I now propose this new one:
"Many Vulgar Earthlings Make Junior Satellites Unilaterally Nonexistent"

copyright Steve 2006

[h0ughy (David)]

Originally Posted by anthony2302749

I hear the new this morning, I suppose we now have to change the way we discuss Pluto. We will have to develop a completely new vocab to describe this object; words such as Minute, Tiny, Diminutive, Miniature, Petite, Undersize, Planetesimal and Dwarf all which are very apt. My favourite at the moment is “Diametrically challenged” it avoids the problem of being political incorrect.

I agree, profound but true, when you have a moon almost as big as you why would you be a planet?