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I am not going to argue with anyone about it, but Pluto is still a planet in my opinion.
Just ask the New Horizons folks, like Alan Stern. https://en.wikipedia.org/wiki/Alan_SternMistrBadgr wrote: ↑Fri Aug 27, 2021 1:41 amI am not going to argue with anyone about it, but Pluto is still a planet in my opinion.
Stern has become particularly involved in the debate surrounding the 2006 definition of planet by the IAU. After the IAU's decision was made he was quoted as saying "It's an awful definition; it's sloppy science and it would never pass peer review" and claimed that Earth, Mars, Jupiter and Neptune have not fully cleared their orbital zones and has stated in his capacity as PI of the New Horizons project that "The New Horizons project [...] will not recognize the IAU's planet definition resolution of August 24, 2006."[43][44]
A 2000 paper by Stern and Levison proposed a system of planet classification that included both the concepts of hydrostatic equilibrium and clearing the neighbourhood used in the new definition,[45] with a proposed classification scheme labeling all sub-stellar objects in hydrostatic equilibrium as "planets" and subclassifying them into "überplanets" and "unterplanets" based on a mathematical analysis of the planet's ability to scatter other objects out of its orbit over a long period of time. Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune were classified as neighborhood-clearing "überplanets" and Pluto was classified as an "unterplanet". One could take this classification system as planet and dwarf planet respectively, with the major difference of the IAU definition classifying the two as distinct categories of celestial bodies instead of two subsets of planets.
Second actually, I stated above there are 9 planets and 4 minors
Correct. I should have said "before me" rather than "first". I've grown tired of often being the first to chime in on that.Lady Fraktor wrote: ↑Fri Aug 27, 2021 3:56 amSecond actually, I stated above there are 9 planets and 4 minors
Clyde Tombaugh deserves more credit!
notFritzArgelander wrote: ↑Fri Aug 27, 2021 3:59 am Tombaugh indeed deserves more credit since by any sane definition of planet Pluto is one. For my money so is Ceres.
As long as its shape is determined by hydrostatic equilibrium between gravity and pressure and it assumes a spheroidal form and NOTHING nuclear is going on, it's a planet, dad gum it! :flame:Graeme1858 wrote: ↑Fri Aug 27, 2021 5:42 amnotFritzArgelander wrote: ↑Fri Aug 27, 2021 3:59 am Tombaugh indeed deserves more credit since by any sane definition of planet Pluto is one. For my money so is Ceres.
And Eris and other TNOs and KBOs that don't behave like planets.
Regards
Graeme
notFritzArgelander wrote: ↑Fri Aug 27, 2021 5:54 am As long as its shape is determined by hydrostatic equilibrium between gravity and pressure and it assumes a spheroidal form and NOTHING nuclear is going on, it's a planet, dad gum it! :flame:
Certainly yes! Orbits are chaotic and meaningless in determining what is or is not a planet. That should depend ONLY on the properties of the object itself. Resonances in perturbations drive the high eccentricity of Mercury. There's a small chance of ejecting Mercury from the Solar System. Does that accident make Mercury no longer a planet? There should be many "rogue" planets unattached to any star. That (to me) conclusively demonstrates the shoddy science of making the definition dependent on orbital properties.Graeme1858 wrote: ↑Fri Aug 27, 2021 6:17 amnotFritzArgelander wrote: ↑Fri Aug 27, 2021 5:54 am As long as its shape is determined by hydrostatic equilibrium between gravity and pressure and it assumes a spheroidal form and NOTHING nuclear is going on, it's a planet, dad gum it! :flame:
And irrespective of eccentricity or obliquity?
Wrong. You misunderstand. Counting only spheroids in hydrostatic equilibrium we have the consensus eight plus Ceres, Pluto, Eris, and Sedna. So Beelzebrown & Co. are only looking for #13.With those criteria surely it's not planet 9 or 10 we're searching for but planet 700 and something?
Irrelevant since the TNOs are NOT in hydrostatic equilibrium NOT spheroidal and are shaped by solid state physics forces, not gravity.
Earth is clearly different from the other planets. Pluto was always suspected to be unusual. Each of Mercury, Venus, Mars are also unique. Now that we've been past Pluto we know it is much more active than non planetary TNOs! Much more like a planet! ThePluto is clearly different from the other 8 planets. We didn't know that when it was discovered but we do know now. Not much point hanging onto sentimental labels when we progress in science. We know Pluto is a fascinating thing of beauty, we've been there. But it's not a planet.
Not a hornet's nest (I hope). Just civilized discussion among friends.KingNothing13 wrote: ↑Fri Aug 27, 2021 12:08 pm
I didn't mean to stir up a hornet's nest......just wanted to post an interesting article from a scientist that I've seen speak a couple of times, and have both of his books, signed.
Since no one asked - I don't care what we call Pluto - it's there, it exists, it doesn't matter what in our cosmic transient-ness call it. It was there before humans evolved, it will be there when we disappear.