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'Yes, Pluto Is a Planet' (sfgate.com)

schwit1 quotes a Washington Post perspective piece by the authors of a new book about Pluto: The process for redefining planet was deeply flawed and widely criticized even by those who accepted the outcome. At the 2006 IAU conference, which was held in Prague, the few scientists remaining at the very end of the week-long meeting (less than 4 percent of the world's astronomers and even a smaller percentage of the world's planetary scientists) ratified a hastily drawn definition that contains obvious flaws. For one thing, it defines a planet as an object orbiting around our sun -- thereby disqualifying the planets around other stars, ignoring the exoplanet revolution, and decreeing that essentially all the planets in the universe are not, in fact, planets.

Even within our solar system, the IAU scientists defined "planet" in a strange way, declaring that if an orbiting world has "cleared its zone," or thrown its weight around enough to eject all other nearby objects, it is a planet. Otherwise it is not. This criterion is imprecise and leaves many borderline cases, but what's worse is that they chose a definition that discounts the actual physical properties of a potential planet, electing instead to define "planet" in terms of the other objects that are -- or are not -- orbiting nearby. This leads to many bizarre and absurd conclusions. For example, it would mean that Earth was not a planet for its first 500 million years of history, because it orbited among a swarm of debris until that time, and also that if you took Earth today and moved it somewhere else, say out to the asteroid belt, it would cease being a planet.

To add insult to injury, they amended their convoluted definition with the vindictive and linguistically paradoxical statement that "a dwarf planet is not a planet." This seemingly served no purpose but to satisfy those motivated by a desire -- for whatever reason -- to ensure that Pluto was "demoted" by the new definition. By and large, astronomers ignore the new definition of "planet" every time they discuss all of the exciting discoveries of planets orbiting other stars.

201 of 301 comments (clear)

  1. So... by The+Good+Reverend · · Score: 5, Informative
    1. Re:So... by gman003 · · Score: 1

      Yes. At the very least, any reasonable definition that excludes the "cleared the neighborhood" requirement would mean that Ceres would go back to planet status (currently dwarf planet, previously asteroid), as would Eris, and possibly the other dwarf planets.

      Personally, I am of the opinion that "planet" is correctly defined, except for the "orbiting Sol" part, which should be revised to "orbiting a star" (with "star" defined as "non-singularity body capable of fusing hydrogen", which excludes deuterium-burning brown dwarfs but includes all other stars). "Planet" is primarily an orbit-based characteristic; it fits in a spectrum including "star", "moon", and "small fragmentary body" (dwarf planets, asteroids, comets, KBOs, etc.). I would gladly accept a second set of terms based on physical characteristics, such as "rocky body" (Earth, Luna, Ceres, Mercury), "gas giant" (Jupiter, Saturn), "dirtball" (small asteroids and comets, many moons), and so on.

    2. Re: So... by jd · · Score: 2

      No.

      Pluto has many properties (structure being one) that Ceres and most KBOs do not have.

      Second, should it matter? Once you have a scientific distinction between an asteroid and a planet, you destroy utterly the value of planetary science if you then contrive to select only that Sara which fits a preconceived notion of how many planets a solar system should have.

      Only the planetary science should matter. School kids can have a cutoff point and ignore everything byond, same as they do in all other sciences. They're not going to be burdened by this.

      Planetary scientists, if given data that is insensibly fitted to a theory, to use a Holmsian phrase, ARE going to be burdened. They, in all of this, are the ones who matter.

      --
      It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
    3. Re:So... by plopez · · Score: 1

      try the Greek god of the underworld.

      --
      putting the 'B' in LGBTQ+
    4. Re: So... by jd · · Score: 1

      That would mean a planet ejected be the star becomes a brown dwarf star (as per current definition) and turns back into a planet on recapture.

      Dunno about you, but I'm a little unhappy with this planet-star duality depending on where it is.

      Rule number one in science is that things should be space-invariant and time-invariant. This is clearly neither.

      --
      It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
    5. Re:So... by GrabbaTheButt · · Score: 2

      Hades is the Greek god of the underworld. Pluto is the Roman version.

    6. Re: So... by Opyros · · Score: 1

      Hm. Who is Sara, and what does she have to do with any of this?

    7. Re: So... by viperidaenz · · Score: 1

      Apparently Jupiter isn't big enough to fuse hydrogen
      It needs to be 75 times more massive to fuse hydrogen and 13 times to fuse deuterium like a brown dwarf

    8. Re:So... by viperidaenz · · Score: 1

      So the answer to the question "How many planets in our solar system?" is "What year are we talking about?"
      When I was at school, it was 9
      When my first child started school, it's 8
      Now by the time my second child is at school is could be different again.

      And we're all talking about the same set of objects orbiting the sun.

    9. Re:So... by K.+S.+Kyosuke · · Score: 1

      Just get used to the fact that there are 7 planets. Why does it bother that there are 11 planets anyway?

      --
      Ezekiel 23:20
    10. Re: So... by Antique+Geekmeister · · Score: 1

      Is there any supportable theory of planetary or stellar evolution in which a planet sized object could be "ejected by a star" ? Even stars such as neutron stars, struck by other neutron stars, would eject matter so unstable without the stellar mass of the neutron star that it would explode into gas during its departure from either host star. While larger atoms such as gold have been detected after neutron star collisions, It's unclear that anything like a planet could form from the ejecta.

    11. Re: So... by dryeo · · Score: 1

      I think you're misunderstanding ejected. 2 planets pass by close enough that their orbits are perturbed, one makes a close pass by its star and gets accelerated enough to leave the system.
      Some of the leading theories of our solar systems early days have an extra gas giant or two that get ejected from the solar system.

      --
      https://en.wikipedia.org/wiki/Inverted_totalitarianism
    12. Re:So... by Anonymous Coward · · Score: 1

      Earthman, your Mickey Mouse is one big stupid dope!

    13. Re: So... by dryeo · · Score: 1

      Pluto has many properties (structure being one) that Ceres and most KBOs do not have.

      How so? Being more icy? Being in a less circular orbit? Or just discovered by an American?

      --
      https://en.wikipedia.org/wiki/Inverted_totalitarianism
    14. Re: So... by Antique+Geekmeister · · Score: 1

      That could be what was meant. If so, I'd like to clarify the language. I'm not sure what phrase would be more clear. There were some older theories of planetary formation that included extrusions happening from stellar passby's, but those have been almost entirely discarded.

    15. Re: So... by dryeo · · Score: 1

      Well the over poster did continue to say recapture, which to me implies gravitational ejection.

      --
      https://en.wikipedia.org/wiki/Inverted_totalitarianism
    16. Re:So... by LynnwoodRooster · · Score: 1

      Because you can only count to 17 by using your fingers and toes. So when you have to add your nose to get to 21, you have too many planets.

      --
      Browsing at +1 - no ACs, I ignore their posts. So refreshing!
    17. Re: So... by mysticgoat · · Score: 1

      I personally find any "scientific" taxonomy that requires the pre-existence of a theory to be... absurd.

      The empirical method involves observations, then the development of a taxonomy based on repeatable observations, and only then the development of a theories. If you decide on your theory first, you do not get Darwin's origin of species, nor do you get the periodic table of the elements. What you get is what happens when the Church persecutes Galileo because his discoveries cast doubt on accepted theory as approved by an august body of authoritarian supporters of the status quo.

      I don't hold the IAU responsible for this fiasco. The responsibility resides in rogue elements of the IAU who took advantage of the general torpor that can set in at the end of a lengthy convention. I do expect the IAU to develop some rules regarding quorum when considering proposed statements made in its name.

    18. Re:So... by Aighearach · · Score: 1

      Definitely a dog philosopher. For every Voltaire there has to be a Kant.

      But surely a Dwarf Planet is a Planet, just as a Dwarf Poodle is a Dog, and a Dwarf Human is a Human.

      And yet, it is also still true that a random rock that was first distant rock somebody spotted isn't the same thing as a planet. Unless you love it so much that you're anthropomorphisizing it; then it is definitely still a Planet. So Dwarf Planets should feel like a real planet, even though they're not listed together with the other planets.

    19. Re: So... by MakerDusk · · Score: 1

      They're calles rogue planets and they outnumber star orbiting planets.

    20. Re: So... by Sique · · Score: 1

      I personally find any "scientific" taxonomy that requires the pre-existence of a theory to be... absurd.

      To the contrary: Every taxonomy needs a founding theory. Terms and words only have a meaning within a theory. That's why for instance "ring" has completely different meanings in Mathematics, in Telephony and in Wedding ceremony.

      It doesn't make sense to discuss the meaning of words without first agreeing on a common theory the words are part of.

      To go back into Astronomy: In the Inka terminology, there are also constellations, but they are completely different from the Mediterran ones we use. Even the word 'constellation' does not make much sense for the Inka, as they don't look at individual stars which might have some position related to others and thus form pictures in the night sky. Quite different, their "star pictures" consist of the dark between the stars, especially along the Milky Way. To us, their constellations look like a shadow play in the sky. As you can see, to even name something in the sky, at first you have to have a theory of it.

      --
      .sig: Sique *sigh*
    21. Re:So... by viperidaenz · · Score: 1

      It wouldn't be so bad if the number kept getting higher as more planets are discovered

    22. Re: So... by dcw3 · · Score: 1

      Rule number one in science is that things should be space-invariant and time-invariant. This is clearly neither.

      Huh? There are plenty of things that change and are called something else. Off the top of my head...

      Water->Ice->Steam
      Meteor->Meteorite
      Lava->Igneous rock
      Star->Black Hole

      --
      Just another day in Paradise
    23. Re:So... by gtall · · Score: 2

      Reminds me of a comment as reported in No Laughing Matter by Joseph Heller. They had a group of men who would go out and eat dinner together periodically. Someone asked how come some other person wasn't invited seeing as he was short like the rest of them. The response was, he was too short.

      Speaking of their dinner club, they had a rule about wives: it was okay for you to bring your wife, it is not okay for me to bring mine.

      Related in that book is the Guillain-Barre syndrome that Joseph Heller contracted (now they have much better treatments). It robs you of motor function. Heller is seated in his wheel chair in his apartment and his buddies are over so they can all go to dinner together. Mel Brooks is one of his buddies. When the time comes to leave, Brooks gets up, walks over to Heller, and in a loud voice says (paraphrase) "Walk, in the name of Jesus". Of course nothing happens. Brooks shrugs his shoulders says to the effect, "Hell, I thought I'd give it try". (Heller and Brooks are Jewish).

    24. Re: So... by jd · · Score: 1, Interesting

      Pluto is layered, for a start. Ceres is much more homogeneous.

      Pluto has liquid water and a liquid core. Ceres has no liquid water and has no core at all.

      Pluto is stable, Ceres is slowly evaporating in the solar winds.

      Pluto has an active geology, Ceres does not.

      Will this suffice or should I add more?

      --
      It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
    25. Re:So... by plopez · · Score: 1

      I stand corrected. But why this obsession with the god of death and the underworld? Should we name a planet "Satan"?

      --
      putting the 'B' in LGBTQ+
    26. Re:So... by Megol · · Score: 1

      You mean the electron flow being in the reverse direction of the current? Because the current is defined as positive and electrons are negative. In most cases it doesn't make any difference at all and there are no need to change it as the definition is still valid.

      The Pluto thing is different. Calling something X when it obviously isn't similar to other objects called X isn't good science.
      It's one thing to say that we have a number of planets all orbiting the sun and having some other similarities with one exceptional object, it could be acceptable with perhaps two exceptions that people agree are borderline planets. But then we add a lot of other objects and it all breaks down - the definition suddenly stops being relevant and new definitions called something other have to be used to separate the planets into relevant categories.

      But the most important thing here is that people remember that Pluto didn't change after being demoted. It's still there and will still be long after the last human have died. It doesn't care if we call it a planet or a fruit.

    27. Re:So... by Dragonslicer · · Score: 1

      All of the other planets are named for Roman gods. Pluto was the most significant god left without a planet named for him.

    28. Re: So... by Dragonslicer · · Score: 1

      Rule number one in science is that things should be space-invariant and time-invariant. This is clearly neither.

      Huh? There are plenty of things that change and are called something else. Off the top of my head...

      Water->Ice->Steam Meteor->Meteorite Lava->Igneous rock Star->Black Hole

      Most of those things don't change names only because they move to a different location or because X seconds have elapsed. Meteor/meteorite is a better example, as would be lava/magma. The rest of your examples involve changes in atomic-level structure due to things like change in temperature.

    29. Re: So... by Argos · · Score: 1

      Exactly! A very rich American.

    30. Re: So... by dryeo · · Score: 1

      The AC posted what I would have.

      --
      https://en.wikipedia.org/wiki/Inverted_totalitarianism
    31. Re:So... by squiggleslash · · Score: 1

      Yes, and why is that a problem? Why does it scare you, rather than blow your mind and fire your imagination, that there might be 100s of planets in our solar system?

      --
      You are not alone. This is not normal. None of this is normal.
    32. Re: So... by jd · · Score: 1

      We count the atmosphere of Earth and Jupiter. Include the atmosphere on Pluto and it's bigger than Earth.

      The AC got everything wrong, New Horizons established a lot of things.

      --
      It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
    33. Re:So... by Green+Mountain+Bot · · Score: 1

      Yes. So?

    34. Re:So... by Green+Mountain+Bot · · Score: 2

      If we want to be pedantic (and this being /., we do), Uranus and Earth aren't named after Roman gods. Uranus named after the Greek god of the sky Ouranos (the Roman equivalent was Caelus), and Earth is named after dirt.

    35. Re: So... by Green+Mountain+Bot · · Score: 1

      That is essentially always what is meant when someone says a planet was ejected by a star. It is a common phrase that comes up most frequently when discussing rogue planets (which are not planets by the IAU definition).

    36. Re: So... by Green+Mountain+Bot · · Score: 1

      Given that a meteor is a meteorite when it burns up in the atmosphere (thus is altered into something else entirely), it is also a bad example. You may as well include "Wood->Fire".

    37. Re:So... by Dragonslicer · · Score: 1

      Uranus named after the Greek god of the sky Ouranos (the Roman equivalent was Caelus)

      Good call, I had forgotten that. Thanks.

      and Earth is named after dirt.

      That could start a pedantic discussion of godlike proportions. You could argue about when, if ever, "Earth" was named, especially since the word "earth" predates the idea that Earth is a planet. It's similar to when the sun was named Sol, since that's just the Latin word for sun.

      And then there's always the ultra-pedantic argument that Earth can't be a planet because the original definition of "planet" was (what people thought was) a star that changed position in the sky as seen from Earth.

    38. Re: So... by Dragonslicer · · Score: 1

      "Meteor" is the name used when it enters the atmosphere, and "meteorite" is the name used when it reaches the surface (assuming it doesn't completely burn up before then). I don't think burning is strictly part of the definition of either word, it's just a natural consequence of moving through the atmosphere.

      It's not a perfect example of something that changes name just because it changes position, since, as you pointed out, there are other changes that typically go along with it, but it's definitely better than examples like water/ice/steam or star/black hole.

    39. Re:So... by Green+Mountain+Bot · · Score: 1

      Calling something X when it obviously isn't similar to other objects called X isn't good science.

      I assume, then, that you will be calling for the demotion of Earth, given how dissimilar it is from Jupiter, Saturn, Uranus, and Neptune - you know, the "real" planets.

    40. Re: So... by david_thornley · · Score: 1

      We have to count the atmosphere of Jupiter (or I'm way out of date on my planetary science) because there's no actual surface. Counting the atmosphere of the more solid planets seems a bit pointless.

      --
      "When you have eliminated the unacceptable, whatever is left, however improbable, must be the truthiness" - Holmes
    41. Re:So... by angel'o'sphere · · Score: 1

      It is nevertheless the same god, and all planets are named after the roman names anyway (in our society).

      --
      Cost free eBook I read (by iBook/Kobo/Amazon/ObookO/Gutenberg etc.): "The Green Odyssey" by Philip Jose Farmer.
    42. Re: So... by angel'o'sphere · · Score: 1

      A brown dwarf star is a "star" that is a bit bigger than Jupiter, but not big enough to ignite fusion.
      Of course you could have a "brown dwarf" as a planet or companion of a main star ...

      Obviously the definition is fussy, as you can not really define things that are fussy by nature.

      When is a girl fat? Obviously when she is overweight enough that you don't find her sexy anymore. On the other hand in a different culture that might be different. Or when is a girl sexy? When it is not to fat? Again that could be completely different defined in an other culture.

      --
      Cost free eBook I read (by iBook/Kobo/Amazon/ObookO/Gutenberg etc.): "The Green Odyssey" by Philip Jose Farmer.
    43. Re:So... by angel'o'sphere · · Score: 1

      We could count like the ancients did:
      You count the planets you can see with the naked eye: Mercury (extremely rarely visible), Venus, Mars, Jupiter, Saturn (also extremely rarely visible).
      Obviously we skipped earth.
      However the reason why ancient arenas had 5 lanes for running / horse racing is: because there are 5 visible planets for the naked eye. But most people will never see Saturn during their live time. In ancient times because they statistically died to early in our times because of light pollution (and Saturn is statistically only twice during your live close enough to be seen with the naked eye)

      --
      Cost free eBook I read (by iBook/Kobo/Amazon/ObookO/Gutenberg etc.): "The Green Odyssey" by Philip Jose Farmer.
    44. Re: So... by jd · · Score: 1

      Of course there's a surface. For a start, you can't have gasses near the interior.

      Secondly, the largest super-Earths known should be gas giants. All solar system formation models show these would have been planets similar to Saturn or Jupiter. Imagining Jupiter is a special case is... stupid.

      Atmospheres are counted because they are physically part of the planet. Same reason the corona is part of the comet.

      Sorry, this is established stuff.

      --
      It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
    45. Re: So... by gman003 · · Score: 1

      *Things* should be invariant. But labels for those things can change over varying place, if the label is inherently locational. What separates an asteroid from a meteorite, but whether it's on the ground or not?

      The term "planet" is already somewhat orbit-based, because otherwise many of the moons, such as Titan, would be classified as planets, but I've never heard anyone argue it should be. That is to say, the intuitive understanding of the word "planet" seems to contain "directly orbits a star" as one of its criteria.

      I would much rather resolve the ejected planet issue you found by classifying such things as "rogue planets" - things that would be planets except for that one criterion of a stellar orbit.

    46. Re: So... by Anonymous Coward · · Score: 1

      Loved that movie!

    47. Re:So... by LynnwoodRooster · · Score: 1

      Does that work for non-binary star systems, though?

      --
      Browsing at +1 - no ACs, I ignore their posts. So refreshing!
    48. Re: So... by dryeo · · Score: 1

      We don't count the atmosphere of the Earth otherwise we'd be arguing where the atmosphere ends and therefore what the radius of the Earth is and Jupiter is mostly atmosphere with an unknown core. Same with Saturn.

      Ceres may have an underground ocean, not that that means anything. Ceres shows signs of volcano-ism and has few craters which shows the surface has been reworked. And where do you get the idea that Ceres is evaporating any more then any planet that is close enough to the Sun for solar affects?

      Most of your arguments would say that Mercury is not a planet.

      --
      https://en.wikipedia.org/wiki/Inverted_totalitarianism
    49. Re:So... by KingBenny · · Score: 1

      semantics in science, please don't let fact get in the way of zbelling

      --
      Free speech was meant to be free for all... how can anyone grow up in a nanny state ?
    50. Re: So... by RockDoctor · · Score: 1

      A brown dwarf star is a "star" that is a bit bigger than Jupiter, but not big enough to ignite fusion.

      No. A planet is a body large enough to be doing the throwing-around amongst it's regions orbiting bodies (rather than being one of the "thrown around") AND which is too small to ignite ANY form of fusion ; a brown dwarf is an orbiting body which (temporarily) achieves deuterium fusion (which is hard to tell, but does leave a noticeable depletion of lithium compared to primordial matter - observationally tricky, but do-able) ; and a star is something that achieves fusion of 1-hydrogen into helium.

      The orbiting criterion is tricky to define, since half of all hydrogen-fusing stars are in binary or higher-order multiples.

      Of course you could have a "brown dwarf" as a planet or companion of a main star ...

      Until some time last year, all the brown-dwarf candidates were in binaries (or higher) - because then it's much easier to measure the masses. But A free-floating brown dwarf was reported last year. Which makes it hard to get the spectroscopic data to prove that the lithium has been depleted.

      No, it's not the world's most wonderful taxonomy.

      --
      Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"
    51. Re:So... by RockDoctor · · Score: 1

      But most people will never see Saturn during their live time. In ancient times because they statistically died to early in our times because of light pollution (and Saturn is statistically only twice during your live close enough to be seen with the naked eye)

      Where the fsck did you get that? I don't have particularly good vision - my limiting magnitude is about 5.6 to 5.7 - but I see Saturn tens of times most years.

      Actually ... you could be thinking about Uranus - which does occasionally get to the point of being naked-eye visible (up to magnitude 5.5) and was recorded in at least one pre-instrumental star catalogue in the right place and magnitude - but not identified as moving. Or possibly Ceres, which can just pull the same trick, allegedly.

      --
      Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"
    52. Re: So... by RockDoctor · · Score: 1

      The AC got everything wrong, New Horizons established a lot of things.

      So, you haven't been paying attention to the data being returned from the Dawn mission over the last year and a bit?

      --
      Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"
    53. Re: So... by david_thornley · · Score: 1

      Exactly what is the surface like, and where is it? Is it something a sufficiently strong being could walk on? Clearly there has to be a rock-atmosphere boundary somewhere, but what's it like?

      Counting the atmosphere as part of a planet is a little iffy. You can tell where the rock leaves off, but the boundary of the atmosphere is arbitrary. For most planets, it doesn't really matter. For gas giants, the atmosphere is a significant part of the mass of the planet, and leaving it off would be inappropriate. Moreover, the atmosphere is what we see when looking at gas giants.

      --
      "When you have eliminated the unacceptable, whatever is left, however improbable, must be the truthiness" - Holmes
    54. Re:So... by angel'o'sphere · · Score: 1

      You are correct,
      I mixed up Saturn with Uranus.

      --
      Cost free eBook I read (by iBook/Kobo/Amazon/ObookO/Gutenberg etc.): "The Green Odyssey" by Philip Jose Farmer.
    55. Re: So... by angel'o'sphere · · Score: 1

      Most brown dwarfs we know about don't orbit anything ... except you want to count systems with multiple stars.
      Brown dwarfs are considered (failed) suns, not planets.

      --
      Cost free eBook I read (by iBook/Kobo/Amazon/ObookO/Gutenberg etc.): "The Green Odyssey" by Philip Jose Farmer.
    56. Re: So... by RockDoctor · · Score: 1

      Most brown dwarfs we know about don't orbit anything ... except you want to count systems with multiple stars.

      Approximately HALF of all stars are in multiple systems - which if you think about it means that about 2/3 of star systems are singletons like the Sun, one third are double stars (approximately matching the number of singleton stars), and then there are a small proportion of triples, quadruples and upwards also bumping the numbers to approximate parity. That is a result that has ben known about for ... well back into the early days of photographic astronomy, and is nothing to do with exoplanets, brown dwarfs or anything. It is a hard number to get a good census on, because it requires observations over a large time span (for distantly-spaced multiples), and often the brightness ratio is large leaving the minor component(s) obscured by the glare of the primary.

      In line with this, and because of the relative ease of (1) spotting stars which are not brown dwarfs and (2) showing the the mass of a putative brown dwarf is in the right range, it is only relatively recently - a few years ago - that the first brown dwarf was found which was not in a binary or higher system. There may have been more discoveries now - but given the observational biases above, they're likely to remain relative rarities. And getting an accurate count is going to be even harder than for (e.g.) small red dwarfs.

      Because brown dwarfs are considered to have formed by direct gas-cloud collapse like other stars, you'd expect their mass distribution function to follow that for higher-mass stars, and so be strongly biased to lower-mass stars. Similarly you'd expect the multiplicity distribution to also reflect that of larger stars, with around a half of them being singletons and the rest in larger systems. But the observability bias would remain.

      --
      Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"
  2. How is fitness a planet? by Anonymous Coward · · Score: 1

    I drove by a gym and a restaurant claiming to be planets!! It seems like the definition must still be pretty broad.

    1. Re:How is fitness a planet? by Narcocide · · Score: 1

      Planet Hollywood sees your attempt to bring prejudice into the discussion (How dare you claim that corporations can't be planets!?!) and raises you one discrimination lawsuit.

    2. Re:How is fitness a planet? by cyberchondriac · · Score: 1

      Sometimes I think Hollywood is definitely it's own planet. Or from a different one.

      But when I hear 'Planet Hollywood', I think, "Yippee-ki-yay, Adrian, I'll be baaack.".

      --

      Look back up at my post, now look back down, you're on the Internet. Now look back up. I'm a signature.
  3. What about Neptune by meerling · · Score: 4, Insightful

    Pluto and it's moons are a pretty significant set of objects, and they cross Neptunes orbit, so does that mean Neptune is no longer a planet since it sure as heck hasn't "cleared it's zone" ?

    1. Re:What about Neptune by techno-vampire · · Score: 4, Informative

      No. Pluto's orbit only seems to cross Neptune's in a 2-D representation. If you look at a 3-D version, you'll see that Pluto's is highly inclined to the Ecliptic, and the closest the two planets get to each other is about 8 AU, or 744,000,000 miles.

      --
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    2. Re:What about Neptune by ShanghaiBill · · Score: 2

      Pluto and it's moons are a pretty significant set of objects, and they cross Neptunes orbit

      Pluto does not cross Neptune's orbit. Pluto's orbital perigee is within the radius of Neptune's orbit, but it is inclined by 17 degrees, so they are nowhere near each other. The minimum distance is 17 AU or about 1.6 Billion miles.

      Pluto is in a 2:3 resonance with Neptune, so in that sense Neptune has "cleared" it.

      Pluto actually gets closer to Uranus (11 AU) than it gets to Neptune.

      so does that mean Neptune is no longer a planet since it sure as heck hasn't "cleared it's zone" ?

      Then there are no planets, since comets pass through all of their orbits. Zone clearing means non-transients.

    3. Re:What about Neptune by TrancePhreak · · Score: 5, Informative

      I looked this up to see what it was like and wow it is way off from all the others. https://theskylive.com/3dsolar...

      --

      -]Phreak Out[-
    4. Re: What about Neptune by jd · · Score: 1

      According to QI, Earth has tens of thousands of non-transient objects in its path.

      --
      It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
    5. Re: What about Neptune by jd · · Score: 2

      You can either have a valid definition and see what that gets you, or you can have a contrived definition arranged to fit a preconceived fact.

      I do not encourage being insensibly drawn to fitting facts to theories.

      Should we define a particle specifically to exclude electrons? Would that be useful or useless?

      Who cares how large things are? Where is that a useful property to measure?

      The only properties that matter are the properties that are invariant in a category and linearly separate themselves from another category.

      Think dichotomous key that holds true for all exoplanets and rogue planets, that is based on fundamental properties that can be used in planetary science.

      If that means there are only 3 planets, 33 or 333, who the hell cares? Reality is what it is, it is not a democracy and it doesn't give a shit whether you like it or not.

      --
      It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
    6. Re: What about Neptune by rmdingler · · Score: 1

      Reality is what it is, it is not a democracy and it doesn't give a shit whether you like it or not.

      Nothing to add... munches popcorn... just thought it should be repeated.

      --
      Happiness in intelligent people is the rarest thing I know.

      Ernest Hemingway

    7. Re: What about Neptune by ShanghaiBill · · Score: 1

      According to QI, Earth has tens of thousands of non-transient objects in its path.

      What is "QI"?

    8. Re:What about Neptune by kiminator · · Score: 1

      "Cleared" doesn't mean no objects cross their orbit. It means there aren't any other objects of comparable size. Pluto is not close to comparable in size to Neptune.

    9. Re: What about Neptune by Plus1Entropy · · Score: 1

      I think we should pick the definition that is the most useful. The definitions are for our benefit after all.

      So if including Pluto in the planet category makes the planet category too broad (less descriptive), then it might be better to place it in the planetoid category instead. There will always be things at the margins that don't fit into either or fit into both. Maybe there are enough of these that another category becomes useful to define, maybe not.

      To take an example from Math: is 1 a prime number? It fits the definition of a prime, but if you include it with the rest of the prime numbers, then pretty much every meaningful statement involving prime numbers has to say "except for 1" (e.g. the Fundamental Theorem of Arithmetic). So even though 1 is technically prime according to the definition, it shares none of the useful properties that prime numbers share, and hence excluding it is more useful. So Mathematicians did exactly that.

      So if we want to say "dwarf planets are planets", that's fine. But if we keep having to clarify "planets that aren't dwarfs", then maybe it is more useful to say that dwarf planets and planets are separate categories (rather than one being a subset of the other). For this reason I prefer planetoid (or even better, Plutoid) to "dwarf planet" as it sidesteps the "linguistic paradox" mentioned in TFA.

      --
      Only crack the nuts that crack. You don't put the ones that don't crack in the sack.
    10. Re:What about Neptune by jouassou · · Score: 1

      Neptune has definitely cleared its zone. The mathematical definition is a planetary discriminant, and Pluto's is 4 orders of magnitude below Neptune's.

    11. Re: What about Neptune by dcw3 · · Score: 1

      Who cares how large things are? Where is that a useful property to measure?

      I take it that you're single.

      --
      Just another day in Paradise
    12. Re: What about Neptune by nine-times · · Score: 1

      You can either have a valid definition and see what that gets you, or you can have a contrived definition arranged to fit a preconceived fact.

      To some extent, it depends on what you're doing and in what way the definition is useful. Is the definition of "planet" a scientific one because "planets" are meaningfully different from the astroids and need to be distinguished for the purpose of scientific study? Or is it just a historical and cultural definition, of the astronomical bodies local to our solar system that we've decided are the "important" ones.

      Because if the definition is historical and cultural, then it's not a contrived definition to identify 9 planets based on the historical significance of their discovery, even if there's not anything to distinguish them scientifically from other objects.

    13. Re: What about Neptune by jd · · Score: 1

      I would agree, if it made it too broad. That's why I've been talking about plotting out the different objects and letting them self-group.

      However, can we come up with a strict definition that is useful and predictive (a key requirement in science)?

      What do we know?

      We know that all asteroids are fairly homogeneous and divide into two groups - rubble piles and cohesive undifferentiated structures. In either case, they are not stratified. They have no atmosphere. They are evaporating under the solar winds. They have no cores. They're incapable of supporting any liquid. None of them have an atmosphere. They have never been geologically active. No magnetic field, past or present.

      We know that all comets have multiple small asteroids in them, encased in a mix of ice and organics. We can regard each of these asteroids as a core, as clearly the ice condensed around a cluster of objects that remained in close proximity through gravity. They evaporate when in close proximity to the sun. They are capable of supporting liquid when evaporating. They cannot retain an atmosphere, but the corona could be classed as a temporary atmosphere. It's very basic, though, and unstructured. The photographs from the lander (the rock piles) and data from Galileo indicate they have some geological activity, but that's kind of obvious. No magnetic field, past or present.

      Mercury has a single liquid core and a magnetic field. Current evidence is that there has been geological activity and it may still be active. It is highly stratified. It doesn't seem to lose much material, but it's hard to say how much it gains. Since it has a liquid core, obviously there are liquids.

      Venus has a single liquid core and a magnetic field. It's intensely active. Most of the planet is liquid. It replaces the crust completely every few decades. The atmosphere is structured, thick, hot and oppressive. Reminds me of Kuro5hin, apart from the structured bit. What it reminds other people of shall remain PG-13, please.

      Earth fits the same pattern. So does Mars, although its geology is mostly dead. It's hard to talk about the geology of the gas giants, but they fit the same pattern otherwise and the atmospheres evolve at a ferocious pace. (In all probability, the gas giants have a core similar to Earth's - liquid surrounding a solid mass.) We don't know much about Neptune, but everything we know fits the pattern.

      Pluto, the only TNO with an atmosphere, liquid water, a liquid core, stratification and an active geology. The atmosphere mirrors that on Mars. Again, it is highly structured. Therefore it structurally and geologically resembles established planets, so we don't have to extend any definitions to include it. Going by the physical and geological properties, then, it is a planet.

      Ceres does not fit this. Vesta might, in part. None of the planetary masses found further out do, although if there's an Earth-sized planet in the belt it probably would. (It's currently thought that such a planet exists, as Pluto can't explain Neptune's orbit perturbation.) And that's the problem. By the IAU's definition, an Earth-sized body that's a KBO is a dwarf planet, even though it's the same size as Earth. By the above differential diagnosis, however, size doesn't matter. It's what the object did with it. Such a thing could, therefore, be a planet.

      --
      It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
  4. Who knows by DontBeAMoran · · Score: 1

    ...they amended their convoluted definition with the vindictive and linguistically paradoxical statement that "a dwarf planet is not a planet."

    Maybe they were trying to uncover A.I. spies?

    I mean this is pretty ridiculous. They say "a dwarf planet is not a planet" and yet they affirm it is a planet by saying so. I mean, the first part does but then they say it's not one. That's the same as trying to convice me that TRUE equals FALSE while I perfaafkly knwaaop tiiss'stt ialllogiccccal+_(%$#@NO CARRIER

    --
    #DeleteFacebook
    1. Re: Who knows by jd · · Score: 1

      Incorrect. Ontologically, a dwarf planet is subcategory of planet. It is a subset, not a distinct class.

      --
      It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
    2. Re: Who knows by dryeo · · Score: 1

      Language is a bit more complicated then that. Is a dwarf tree a tree or shrub? The horticultural books I've read would classify the dwarf tree as a shrub but it is all a grey area with a tree being defined as bigger then a shrub, sometimes the number of stems mattering and sometimes not and what exactly is the cutoff when it comes to size?

      --
      https://en.wikipedia.org/wiki/Inverted_totalitarianism
    3. Re: Who knows by jd · · Score: 1

      Ad that is why botany is a humanity and not a science. You can't predict anything with a definition like that. It's also why geneticists have been throwing out most of the botanical taxa and replacing them with a much more rigorous system.

      All I want is for the same to be applied to physical objects in space.

      --
      It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
    4. Re:Who knows by DontBeAMoran · · Score: 1

      There is only one language precise enough to do philosophy and it's binary.

      --
      #DeleteFacebook
    5. Re: Who knows by dryeo · · Score: 1

      Well I must admit that I've never heard botany described as not science, especially because some botanists use genetics.
      I guess astrophysics isn't a thing because it is fuzzy between stars and brown dwarfs as well. English is just fuzzy at times.

      --
      https://en.wikipedia.org/wiki/Inverted_totalitarianism
  5. Oh dear god, this again? by JoshuaZ · · Score: 4, Interesting

    Seriously, this again? Categories by nature have fuzzy boundaries. We'll have trouble telling how best to categorize the edge cases. What matters is what categories are most useful for understanding things. If the experts in an area decide to categorize something one way then let them.

    To add insult to injury, they amended their convoluted definition with the vindictive and linguistically paradoxical statement that "a dwarf planet is not a planet." This seemingly served no purpose but to satisfy those motivated by a desire -- for whatever reason -- to ensure that Pluto was "demoted" by the new definition.

    If I'm following this argument correctly, they are arguing that it is "linguistically paradoxical" to have something of the form "[adjective] x" to not also be in the category labeled "x". But we do this all the time. For example, in math a "skew field" is not necessarily a field https://en.wikipedia.org/wiki/Division_ring, and one can come up with many other examples in STEM fields. This is a natural thing that we do all the time. And the specific reason in this case that dwarf planets were not planets was to avoid then making Eris and Ceres and a a whole bunch of other objects also planets.

    I'm fascinated that with everything else going on the world, serious people apparently think that arguing over what we call a planet or not is an important issue.

    1. Re:Oh dear god, this again? by jythie · · Score: 2, Interesting

      I doubt people care about pluto itself much, but the debate steps on both nationalism (since Pluto was discovered by an American and children loved it) and intellectualism (standards body vs citizen scientists), so it is symbolic of a pair of much deeper social conflicts going on.

    2. Re:Oh dear god, this again? by Tablizer · · Score: 1

      Categories by nature have fuzzy boundaries

      I too have a fuzzy boundary. I hope exercise and a good shave will take care of it.

    3. Re: Oh dear god, this again? by ljw1004 · · Score: 1

      More examples...

      A red panda isn't a panda
      A red dwarf isn't a dwarf
      A fake Gucci handbag isn't a Gucci handbag

  6. Solution: Pluto "identifies" as a planet. by Anonymous Coward · · Score: 4, Funny

    It's pretty simple. If Pluto identifies as a planet, then it is one. All of this classification by scientists is just an attempt to create a privileged, sexist, and racist system that discriminates against small planetoids.

  7. Settled by jwhyche · · Score: 2

    Well I for one am glad this is finally settled.

    --
    I read at +2. If your post doesn't reach that level I will not see or respond to it.
    1. Re:Settled by thegarbz · · Score: 1

      I know right? I was just waiting for some guys I've never heard of to write a book about it. The science is settled, because that's how science works!
      Opinions!

  8. Jerry has spoken by Anonymous Coward · · Score: 1

    just begs for this clip of Jerry .

  9. Politician == Scientist by drainbramage · · Score: 1

    It seems that 40, 50 years politicians were different.
    Not since.
    This might be the 13th sign of the apocalypse.
    The bakers dozen of failures.

    --
    No brain, no pain.
  10. There's a rather important misunderstanding there by mark-t · · Score: 2

    The reason that they think the IAU's definition of a planet is ambiguous is because they have the definition wrong. A planet does not have to completely clear its neighborhood of all other objects (the earth would not qualify if that were the case, since it shares its orbit with Luna, its moon). What makes it a planet is when it has cleared the neighborhood of all similarly sized objects.

    So yes, Earth would not be a planet if it shared an orbit with a planet like mars or venus, and would be considered either a moon or possibly even an asteroid if it shared an orbit with Jupiter or Saturn, depend on whether it was gravitationally captured by the gas giant or not.

  11. Re:Solution: Pluto "identifies" as a planet. by rogoshen1 · · Score: 1

    Hey, don't expect society to conform to your delusion!

    if you want to play planetary dress up, feel free. but if you were born a planet, then you're a planet.. and no amount of mental gymnastics will change that.

  12. What a stupid article by admiralh · · Score: 1, Troll

    Problem #1: Authors complain that the definition of "planet" doesn't include exoplanets (because they don't orbit the Sun)..
    Solution: Change definition to include other stars or say that the particular star doesn't matter if the other criteria are met.

    Problem #2: Authors complain that the criterion that a planet must "clear its orbit" is imprecise and is dependent on other objects.
    Solution: None needed. Let the IAU define the border cases. As for being dependent on other objects, the point is that for an object to be a planet, it must utterly dominate its orbit, leaving nothing significant.

    Problem #3: By the IAU definition, Earth was not a planet for the first 500 MYears of its existence, because it hadn't yet cleared its orbit. Authors call this "bizarre and absurd".
    Solution: Why is this a problem? There was no guarantee that the Earth was going to survive as a planet. Another Theia-like impact could have ended it.

    Problem #4: It is a linguistic paradox (and vindictive to boot) to say "a dwarf planet is not a planet."
    Solution: So what? A guinea pig is not a pig. Spotted dick is not a dick. Etc.

    It never ceases to amaze me how emotional the "Pluto is a planet" people are and how the MSM gives these people much more publicity then they deserve. In the immortal words of Neil DeGrasse tyson, "Get over it!"

    --
    Hopelessly pedantic since 1963.
    1. Re:What a stupid article by jythie · · Score: 1

      But.. but.. elitist socialists hate america and amatures who are the real source of innovation!

    2. Re: What a stupid article by jd · · Score: 1

      Your solution to #1 doesn't solve rogue planets.

      Your definitions still don't take into consideration the need by scientists for definitions that categorise in ways useful to planetary scientists.

      They're not interested in whether the planet count is single digit in a given number base.

      They care that if you plot the properties of all the objects in the solar system and apply the categorisations, all of the properties and models group perfectly within those categories and that you can falsify a prediction.

      They also care that categories are invariant and independent of externals. An object with a given set of properties will have a given category, no matter what.

      That means a planet identical to Earth orbiting a Super Jupiter should be a planet. It would also be a moon. A moon is a description of a relationship, not a description of an object.

      It means a Super Earth that is a rogue planet is never classed as a brown dwarf star.

      It means that if a Super Earth was found in the Kuipier Belt, it can't be a Dwarf Planet.

      What is do wrong with that?

      It can be done. There are ways to define a planet that have nothing to do with position, relationship or other extrinsics, or with mass or diameter. None of these properties relate to the actual structure, physics, geology or nature of the object.

      If you use those four properties, though, you'd have a very decent intrinsic rather than extrinsic definition. Something that would be useful.

      --
      It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
  13. Yes, that was actually the point by Excelcia · · Score: 5, Interesting

    The whole reason for "demoting" Pluto had nothing to do with Pluto itself. It had to do with Eris. When Eris was discovered, it appeared to be (because of its albedo) larger than Pluto. It is, in fact, more massive tham Pluto is though slightly smaller. Because of its size, the discoverer was making a strong case for having it accepted as the solar system's 10th planet. While this gave NASA a huge ole woody, because they were counting the dollar signs of how a newly discovered actual planet would spur public opinion for exploration, it caused significant consternation at the IAU. That's actually understating things. A few members of the IAU were quite literally horrified at the prospect. They were looking at the fact Michael Brown's team had discovered scads of Trans-Neptunian-Objects, that there very well could be half a dozen or more additional ones the size of Pluto/Eris, and they were quite happy with the set of planets we already had, thank-you-very-much. There was a certain historical congruency to it and no upstart finding a TNO that happened to be as large as Pluto was going to get his name listed in the same breath as such nobility as William Herschel. So they decided that in the end, that since they really couldn't call Eris a planet if Pluto was a planet, they did what they thought was the lesser evil. They preserved the sanctity of the rest of the solar system by demoting Pluto.

    Of course the definition has holes and is not even self-consistent. The whole purpose of it was to demote Pluto and all other similar objects and to ensure that it was worded such that no other TNO could ever be labelled a planet, by nature of being out in the area where nothing is "cleared".

    What people need to ask themselves is this: does the fact that the IAU had its collective head up its ass tell me what I consider to be a planet? The answer for me personally is a big whopping no. And when it comes up in conversation, usually after I name all 9 traditional planets (sometimes adding Eris) and get "corrected" that, hey, don't I know Pluto isn't a planet any more, that's when I let the poor smarty-pants have it with both barrels. Not really their fault, but anyone toeing the IAU party line and not willing to think for themselves deserves to get it.

    The IAU isn't an official body with any authority other than what they have taken on themselves. And if they are going to let historical politics cloud scientific thinking, they certainly aren't going to speak for me. I'd like to see some textbook publishers take a stand too.

    1. Re:Yes, that was actually the point by kiminator · · Score: 1

      Why do you think the IAU should have felt it reasonable to classify dozens of TNOs as planets, when those objects would have been far more similar in properties to other non-planet TNOs than to the objects currently defined as planets?

    2. Re:Yes, that was actually the point by scottrocket · · Score: 1

      ...was going to get his name listed in the same breath as such nobility as William Herschel.

      Not to mention a farm boy named Clyde.

    3. Re:Yes, that was actually the point by Solandri · · Score: 5, Insightful

      The IAU isn't an official body with any authority other than what they have taken on themselves. And if they are going to let historical politics cloud scientific thinking, they certainly aren't going to speak for me. I'd like to see some textbook publishers take a stand too.

      The thing is, if you don't accept the IAU's authority, then whose authority are you going to accept? Textbook publishers? They're one notch above those scammers who sell you the "right" to name a star.

      The IAU's membership is over 12,000 professional astronomers, which as best as I can tell is a pretty good percentage of the people with careers in astronomy. The next largest professional group is the American Astronomical Society, with about 7,000 members all in the Americas. Their stance on the issue is decidedly neutral.

      In the end, the definition of a planet is merely semantics. What's important is that whatever definition you decide to use is functional, allowing generalized statements to be made easily without running afoul of the terminology. In that respect, I don't have a problem with the division between "planet" and "trans-Neptunian object" and dwarf planet. They are different enough and the terms selected for them, although not perfect, are definitive enough to make statements and issue papers about them without tripping over the semantics.

    4. Re:Yes, that was actually the point by Excelcia · · Score: 3, Interesting

      First of all your question assumes facts not in evidence. You are stating as a fact within your question that that Pluto has few similarities to the other eight planets. While it's difficult to nail down Pluto's geology precisely, best evidence suggests that Pluto has a rocky/metalic core, a probably liquid mantle, and a solid crust. How much other differentiation there are between layers (an outer/inner mantle, outer/inner core) is pure guesswork right now, but as it stands it has quite similar enough geology to the other eight planets for me to recognize it as belonging.

      Secondly the way your question is worded also suggests that, to you, somehow the number of planets in the solar system is a problem. Who cares if it's just Eris or a dozen more? If they are large enough for gravity to pull them into a sphere, if they are geologically and structurally similar to the other planets, how is the number of them even relevant? That's not evidence-based science at all. That's letting your comfort-level with the result determine what you accept as results.

    5. Re:Yes, that was actually the point by dryeo · · Score: 1

      The real problem was that Pluto was ever considered a planet, given the history of Ceres. It is just not big enough compared to the rest and its orbit is quite different then the rest.
      At the time of its discovery there were arguments about it and one of the reasons it was accepted as a planet was due to being an iceball, it looked bigger (brighter) then it actually is. Originally comparable to Mercury in size, the estimates kept shrinking its size until really it is more comparable to an asteroid.

      --
      https://en.wikipedia.org/wiki/Inverted_totalitarianism
    6. Re:Yes, that was actually the point by Excelcia · · Score: 1

      I was arguing on behalf of Pluto. Was that actually unclear?

    7. Re:Yes, that was actually the point by dj245 · · Score: 2

      The IAU isn't an official body with any authority other than what they have taken on themselves. And if they are going to let historical politics cloud scientific thinking, they certainly aren't going to speak for me. I'd like to see some textbook publishers take a stand too.

      The thing is, if you don't accept the IAU's authority, then whose authority are you going to accept? Textbook publishers? They're one notch above those scammers who sell you the "right" to name a star. The IAU's membership is over 12,000 professional astronomers, which as best as I can tell is a pretty good percentage of the people with careers in astronomy. The next largest professional group is the American Astronomical Society, with about 7,000 members all in the Americas. Their stance on the issue is decidedly neutral. In the end, the definition of a planet is merely semantics. What's important is that whatever definition you decide to use is functional, allowing generalized statements to be made easily without running afoul of the terminology. In that respect, I don't have a problem with the division between "planet" and "trans-Neptunian object" and dwarf planet. They are different enough and the terms selected for them, although not perfect, are definitive enough to make statements and issue papers about them without tripping over the semantics.

      And yet only 424 of them were allowed to vote on the matter, on the last day of a conference.

      I can't find the source, but I read somewhere that a previous measure, agreed to by most, would have preserved Pluto as a planet. Thinking the matter settled, most of the delegation went to play golf or drink beer, and a small minority pushed their agenda through.

      --
      Even those who arrange and design shrubberies are under considerable economic stress at this period in history.
    8. Re:Yes, that was actually the point by mysticgoat · · Score: 1

      So the IAU is basically a religious organization intent on preserving the sanctity of their belief system? Oh wait, that is just one faction within the IAU. The IAU's problem is really that it had not developed a meaningful concept of "quorum" in time to prevent it from being subverted by a group of reactionary radicals.

    9. Re:Yes, that was actually the point by careysub · · Score: 3, Interesting

      The whole reason for "demoting" Pluto had nothing to do with Pluto itself. It had to do with Eris....

      Everything you say is true, but it gets much, much worse.

      They concocted this contrived definition of "planet" not long before we started finding lots more planets, thousands of them.

      The IAU needs to sit down with all the exo-planet astronomers, and planetologists (like geologists, but not restricted to Earth), and think this through from the beginning, and come up with consistent, science-based classifications, and let the chips fall where they may - not use a pre-determined "correct" number of planets for the Solar System.

      Of course the very term "planet" is of ancient origin and referred to those permanent naked eye lights in the sky that weren't stars. There were only the original set until William Herschel discovered Uranus (well, Earth too - after Copernicus). When asteroids were first discovered, they were planets too until astronomers realized they were dozens of them, make that hundreds of them, make that thousands of them. So the term never had a firm scientific definition.

      I think a more complex classification system is called for myself. It is true that Pluto and Eris are a new class of body - Kuiper Belt Objects, just as asteroids were and are, but that doesn't mean they can't also be planets. Now that we know of some 4,500 confirmed or candidate planets (which will expand to tens of thousands in a decade or so) it is ridiculous to use those ancient six plus two planets as the standard to define what the term means.

      --
      Starships were meant to fly, Hands up and touch the sky - Nicky Minaj
    10. Re:Yes, that was actually the point by jouassou · · Score: 3, Interesting

      Being large enough for gravity to deform it into a ball is one possible definition, and looking at it's geological structure is another. The latter would likely disqualify the gas giants, but you could probably make several definitions for "gas planet" and "rock planet", for instance. But I'd still call the IAU definition a science-based alternative as well.

      There is a gap of several orders of magnitude in the so-called planetary discriminant between typical "planets" (50-50,000) and "dwarf planets" (<0.03), which indicates that there really is a qualitative difference between these. Personally, I don't see the problem with having a two-tier classification scheme where something deformed into a ball classifies as a dwarf planet, and a dwarf planet that is dominant in its region of space classifies as a large planet. It's also a definition that fits with the historical notion that moons and asteroids are not "planets" (even though e.g. Ganymede is larger than Mercury).

    11. Re:Yes, that was actually the point by dcw3 · · Score: 1

      Isn't that a bit like saying, if your penis is small enough, we should call it a clitoris?

      --
      Just another day in Paradise
    12. Re:Yes, that was actually the point by Anonymous Coward · · Score: 2, Insightful

      This! This got me upset. I'm not a member of the IAU, but an amateur who has a degree in physics and has taken astronomy, astrophysics and planetary geology courses at the graduate level.

      Astronomers play politics.... this one got nasty. Then NASA got involved, then celebrities and it snowballed. I still answer 9 when asked how many planets there are by a kid when he looks through my telescope. Most people I know do too... including professors of astronomy... but there is a small minority who loves beating you over the head when you make this error and somehow fail their mental Jeopardy game on a technicality. I call them dumb smart-asses.

      If the classification system was logical, consistent and broadly accepted by the larger IAU, I would go along with it. But Pluto is a thorny subject... transneptunians are a problem of classification in general and will continue to be more so as we learn more about the solar system. Why not wait until we have a better classification system? Why play politics and demote Pluto in the popular consciousness so early?

      I would have been on the other side of the fence and allowed more objects into the planet club. It gets people excited and interested in astronomy. Then when it gets ridiculous (15+ planets), bring in a more rigid planet definition and end up with 8 or 9. I would have no problems with this approach.

      But self important committee members being what they are, gave us a shock political demotion followed by a witch hunt for hold out heretics. Most astronomers remain heretical, but silent.

      Just my two cents.

      I leave you this for your enjoyment about the past political antics astronomers have been known to partake in when the discovery credit for a planet was at stake:

        Le Verrier vs Adams

    13. Re:Yes, that was actually the point by thegarbz · · Score: 1

      I can't find the source, but I read somewhere that a previous measure, agreed to by most, would have preserved Pluto as a planet.

      That is a problem of direct democracy. Just because there are 12000 members doesn't mean most of them have skin in the Pluto game beyond childhood memories. Having disconnected people voting on a contentious topic is not the way to come up with a useful definition. Most of those astronomers couldn't give a shit about the planets in our solar system. Astronomy is a huge field.

    14. Re:Yes, that was actually the point by cshamis · · Score: 1
      Planet or not a planet. When we discovered the first 9, we thought we had it figured out. Within the limits of our instruments and understanding we had a good definition. Then... we started finding all sorts of things that didn't fit the model. So they came up with a new definition. But... they blew that too. But, now they're just messing with definitions of classification to get the answer they want. Ok, it's not science any more.

      So. Here's how I'm going to view it. Our solar system contains 9 orbiting bodies I call planets, and a bunch of other stuff that isn't. I say this with the full knowledge that if we(people) knew then, what we know now, we would probably have not have made the same call. --But it's too late for that. It's done. I'm moving on. Pluto is a planet. Please tell Neil to get over it. :-)

      But, a little more seriously, there's some precedent: Newton's laws of motion are still called laws, even though we know they're not (thanks Einstein). And, you don't get stripped of your PhD if somebody comes along two years later and completely disproves your thesis. We can do the same for the planets. I mean, really, it's just an arbitrary naming convention. It does'nt help us infer new understandings about the subject mater. It's a just a silly argument.

      Which I guess, just goes to show how human scientists are.

    15. Re:Yes, that was actually the point by dryeo · · Score: 1

      Not really, more like saying a plant is a shrub rather then a tree based on its size and number of stems. It's fuzzy.

      --
      https://en.wikipedia.org/wiki/Inverted_totalitarianism
    16. Re:Yes, that was actually the point by rossdee · · Score: 1

      "The IAU needs to sit down with all the exo-planet astronomers, and planetologists"

      I don't think the IAU has any jurisdiction outside our solar system.

    17. Re:Yes, that was actually the point by Green+Mountain+Bot · · Score: 1

      Why do you think the IAU should have felt it reasonable to classify Earth, Venus, Mercury, and Mars as planets, when those objects would have been far more similar in properties to other non-planet TNOs than to Jupiter, Saturn, Uranus, and Neptune?

    18. Re:Yes, that was actually the point by Green+Mountain+Bot · · Score: 1

      There is also a gap of several orders of magnitude between Mars and Jupiter. Also, it should be noted that these measures are influenced by orbital distance, which is not an intrinsic property of the body in question. And that's the problem with the two tiered system of names. To get there, you have to depend on information that is not intrinsic to the thing being named.

    19. Re:Yes, that was actually the point by Green+Mountain+Bot · · Score: 1

      Here's how I'm going to view it. Our solar system contains 9 orbiting bodies I call planets, and a bunch of other stuff that isn't.

      So, how do you separate "planets" from "Pluto-sized objects orbiting the sun"?

      So, WHY do you separate "planets" from "Pluto-sized objects orbiting the sun"?

    20. Re:Yes, that was actually the point by Green+Mountain+Bot · · Score: 1

      Why does the orbit matter at all when discussing whether an object is a planet or not? Triton orbits the opposite direction of every major moon in the solar system. We don't say it's not a moon. And who decides what's big enough compared to the rest? Pluto is a lot closer in size to Earth than Earth is to Jupiter. Why is Earth considered to be the same thing as Jupiter but an entirely different thing than Pluto?

    21. Re:Yes, that was actually the point by Green+Mountain+Bot · · Score: 1

      That doesn't mean they can't learn a thing or two from extra-solar scientists.

    22. Re:Yes, that was actually the point by dryeo · · Score: 1

      Orbit by itself doesn't matter that much, it is when combined with small object it may make a difference. Planet is a human invention without a real clear cut definition besides the original wandering object in the fixed sky or whatever it was whereas Moon is the name of the Earths satellite and satellite is simply an object orbiting another object, so Titan is a satellite of Neptune and Neptune is a Satellite of the Sun.
      As for the size thing, well at one point when asteroids were being discovered, it was decided that instead of all being planets, they were something else, otherwise we'd have so many planets as to be unmanageable. Same now with Pluto, which seems to be just another member of a class of lots of objects about the same size. We could expand the meaning of planet to include trans-Neptune objects as well as asteroids, but it is kind of like expanding the meaning of trees to include bushes.

      --
      https://en.wikipedia.org/wiki/Inverted_totalitarianism
    23. Re:Yes, that was actually the point by doom · · Score: 1

      This shouldn't have been on /. at all

      Talk about disgruntled autistics-- touch of OCD?

    24. Re:Yes, that was actually the point by RockDoctor · · Score: 1

      It is just not big enough compared to the rest

      That took several decades for people to work out. The question of it's albedo left it's diameter and mass in considerable doubt until the discovery of Charon.

      and its orbit is quite different then the rest.

      That however was realised to be very odd almost from day one. With the exception of some asteroids (a group of bodies that got demoted from "planet" status in about 1860), nothing else had a slightly similar orbit. Until the discovery of the first Centaur, at almost the same time as the discovery of Charon.

      --
      Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"
    25. Re:Yes, that was actually the point by RockDoctor · · Score: 1

      Pluto is a lot closer in size to Earth than Earth is to Jupiter.

      I worked the numbers on this last week. Well, the Jupiter one I've had in my head for years. Jupiter/Earth is 318 (by mass) ; Earth/ Pluto is 458.2.

      --
      Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"
    26. Re:Yes, that was actually the point by dryeo · · Score: 1

      I thought right from the discovery there were people arguing that the albedo was high and Pluto was small though perhaps I'm mis-remembering as I can't find any references.

      Really, because they were looking for a planet (something that was big enough to perturb Neptune's orbit), they found a planet. Even Uranus was briefly considered a comet as that is what Herschel was looking for.

      --
      https://en.wikipedia.org/wiki/Inverted_totalitarianism
    27. Re:Yes, that was actually the point by RockDoctor · · Score: 1
      There are a lot of unknowns when trying to do photometry (measurement of brightness) from photographic plates. For a start, you don't know the sensitivity of each emulsion on each and every pixel on a plate (literally - even if you batch process a pile of plates, you don't know if the "baking in an oven flooded with hydrogen" step has applied the same across every plate in the oven - see photographic hypersensitisation ; then you get onto the vagaries of chemical flow across the surface in the darkroom). Life got terrifically simpler with the introduction of large-area CCDs, but by that point we had Charon to take the uncertainties out of the system. That it was really hard to do photometry on an object near the limit of detectability should surprise no one who has actually worked in a darkroom.

      When Charon took the uncertainties away, it was visible as a non-circularity in the 20-odd micron diameter of the plate image. A decade later - during the era of mutual occultations - the resolution had increased to give around 50 pixels for the deconvolved image. That's just ever-so-slightly a big improvement.

      Around the time of Charon's discovery - I don't have the reference to hand - there was a rather tongue-in-cheek paper describing the problem : since the discovery of Pluto, as photometric methods improved, estimates of it's absolute magnitude and mass had decreased, steeply, with the conclusion that shortly Pluto would disappear. Charon saved it from that fate, but it remains tiny. A large asteroid.

      --
      Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"
  14. Obligatory Rick and Morty reference! by King_TJ · · Score: 1
  15. Re:Never doubted it by sconeu · · Score: 1

    I understand that Pluto prefers the term "Gravitationally Different" to the term "Dwarf"

    --
    General Relativity: Space-time tells matter where to go; Matter tells space-time what shape to be.
  16. Re: Pluto is a swarf planet ! by jd · · Score: 2

    I don't believe in scientific notation designed to limit a group to X. Either the definition is based on sound science or it is crap.

    Pluto is structurally utterly unlike Ceres or any KBO, therefore it is not in the same category as those.

    Pluto is structurally the same as Earth and Mars, therefore that is the category it belongs in.

    Reality is not a popularity contest, I do not give a flying who thinks Pluto is what, it is structurally the same as a planet and is structurally distinct from anything not a planet. Far as I'm concerned, planetary science overrules any ego. The science comes first.

    Any problem with that?

    --
    It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
  17. Re: There's a rather important misunderstanding th by jd · · Score: 1

    The moon is large enough that the Earth and moon are considered a binary planet.

    --
    It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
  18. Re: Sagen Is Rolling In His Grave by Narcocide · · Score: 1

    No, the government put paraquat in his weed.

  19. No, Pluto is not a planet by jader3rd · · Score: 1

    It doesn't orbit the sun on the same plane as the other planets. Pluto just happens to have been an object discovered first at that distance. I'm fine with not calling the Earth a planet, until it cleared it's path around the Sun.

    1. Re:No, Pluto is not a planet by Plus1Entropy · · Score: 1

      It depends. It moves around so sometimes it's inside the Sun and sometimes it's not. It depends on how the planets are oriented relative to one another in their orbit.

      --
      Only crack the nuts that crack. You don't put the ones that don't crack in the sack.
  20. Reminds me of T-Rex by Spy+Handler · · Score: 1

    and the idiot who went around claiming that T-Rex was a scavenger and could not hunt anything. He was a professor of something or another.

  21. All I hear is... by lessthan · · Score: 1

    Wah, wah, wah

    --
    Space Shuttle was a program that strapped humans to an explosion and tried to stab through the sky with fire and math
  22. Re:Never doubted it by rmdingler · · Score: 1

    I understand that Pluto prefers the term "Gravitationally Different" to the term "Dwarf"

    Exactly. It's perfeckly acceptable to refer to Pluto as a G.D. Planet.

    --
    Happiness in intelligent people is the rarest thing I know.

    Ernest Hemingway

  23. Re: There's a rather important misunderstanding th by mark-t · · Score: 1

    The accepted definition of a double planet system is one where the the barycenter, the point around which both bodies orbit, lies outside of both bodies.

  24. Re: Thank God this has been decided by jd · · Score: 1

    It is if you're a planetary scientist. If you don't know what is a planet and what isn't, you can't model either.

    --
    It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
  25. It orbits the Sun and has a name by charliemerritt03 · · Score: 1

    It is "far out", orbits the Sun, has a name.
    PLUTO
    is good enough - who cares about legalities when there are no lawyers out there?

    1. Re:It orbits the Sun and has a name by freeze128 · · Score: 2

      That's a GREAT idea! Send all the Lawyers to Pluto!

  26. Re: There's a rather important misunderstanding t by jd · · Score: 1

    Which was indeed the case 250 million years ago. So the moon was a planet in the relatively recent past. Which means the Earth did not clear its orbit, the moon did.

    --
    It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
  27. "I was big enough for your mom" -- Pluto by hduff · · Score: 1

    Best Pluto joke IMHO

    --
    "I believe in Karma. That means I can do bad things to people all day long and I assume they deserve it." : Dogbert
    1. Re:"I was big enough for your mom" -- Pluto by angel'o'sphere · · Score: 1

      Lucky we have no stupid Uranus jokes here :P

      (just because americans can not pronounce Uranus correctly)

      --
      Cost free eBook I read (by iBook/Kobo/Amazon/ObookO/Gutenberg etc.): "The Green Odyssey" by Philip Jose Farmer.
  28. As long as there's still only 49 states by rsilvergun · · Score: 1

    I'll be deep in the cold cold ground before I recognize Missourah.

    --
    Hi! I make Firefox Plug-ins. Check 'em out @ https://addons.mozilla.org/en-US/firefox/addon/youtube-mp3-podcaster/
  29. Re:Solution: Pluto "identifies" as a planet. by mschuyler · · Score: 1

    OK. I just snorted wine out my nose. Thanks, guys, for my laugh of the day.

    --
    How about a moderation of -1 pedantic.
  30. Re: Pluto is a swarf planet ! by K.+S.+Kyosuke · · Score: 1

    Structurally, structurally, structurally... :-p The eternal conflict between geologists and dynamicists. :D

    --
    Ezekiel 23:20
  31. Re:No Fucking Shit by SpaceDave · · Score: 1

    Doing astronomy public outreach I deal with a lot of people who are angry about the Pluto situation. It's possible that you are the angriest of them all. Are you okay?

  32. 100+ Planets? by Artagel · · Score: 1

    Ethan Siegal at Starts With A Bang (makes the point that https://www.forbes.com/sites/s...) makes the point that what is a planet should be considered in light of what we know about solar system evolution. According to that perspective, it does not appear that Pluto is a planet. If Pluto is a planet, then there are over 100 of them.

    1. Re:100+ Planets? by djinn6 · · Score: 1

      100? Did you forget we found 3,700 planets outside the solar system already?

      Besides, since when does the number of planets have to be limited? If it's round, made of regular matter and not a star, then does its location really matter?

    2. Re:100+ Planets? by meglon · · Score: 1

      I would imagine he's talking about just objects in our solar system (the over 100 reference). As for "round, made of regular matter and not a star," that's a good definition for a basketball too.

      --
      Fascism: An authoritarian and nationalistic right-wing system of government and social organization. See also: NAZI's
    3. Re:100+ Planets? by djinn6 · · Score: 1

      Since I'm not the IAU, I'm not going to create a definition that caters to pedants. You can replace "round" with "round under its own gravity" if that makes you happy.

    4. Re:100+ Planets? by meglon · · Score: 2

      Yes... because science and details never go together....

      --
      Fascism: An authoritarian and nationalistic right-wing system of government and social organization. See also: NAZI's
  33. Re: Pluto is a swarf planet ! by dryeo · · Score: 2

    So you're saying the gas giants aren't planets? Same with the ice giants? And various large satellites are planets?
    Besides I think you might find that Ceres is more like a rocky planet then an iceball like Pluto.

    --
    https://en.wikipedia.org/wiki/Inverted_totalitarianism
  34. Re: There's a rather important misunderstanding t by dryeo · · Score: 1

    Which was indeed the case 250 million years ago. So the moon was a planet in the relatively recent past. Which means the Earth did not clear its orbit, the moon did.

    Huh? What are you talking about? The Moon formed closer to the Earth and is slowly moving away. 250 million years ago it was somewhat closer and in a few billion years it may become a double planet.
    Besides by your definition, Charon is also a planet.

    --
    https://en.wikipedia.org/wiki/Inverted_totalitarianism
  35. Re:Solution: Pluto "identifies" as a planet. by Anonymous Coward · · Score: 1

    You forgot "heteronormative" and "ciscentric," you transphobe.

  36. Cleared its zone? by Tjp($)pjT · · Score: 1

    So Neptune isn’t a planet? Every so often Pluto is closer to the Sun for 20 years... so Neptune has some work to do...

    --
    - Tjp

    I am in wallow with my inner money grubbing capitalistic pig. ... Oink!

    1. Re:Cleared its zone? by meglon · · Score: 1

      ....which is because of Pluto's very eccentric orbit in comparison to the rest of the planets in the planetary plane. That's actually just another ding against Pluto.

      --
      Fascism: An authoritarian and nationalistic right-wing system of government and social organization. See also: NAZI's
  37. view from a linguist by mcswell · · Score: 1

    Speaking as a linguist, this whole discussion on the planethood of Pluto is just silly. Pluto is still the same icy body it always was, what earthly (pardon the pun) difference does it make whether the word "planet" is defined to include it or exclude it? I just don't understand why anyone cares.

    1. Re:view from a linguist by Aighearach · · Score: 1

      The reason that some people care is because when they talk about what "planets" are, it makes a difference if it some small number of large things, or a large number of small things.

      Also, some of them are visible at night and it is useful to have a word that means those things, and not every little icy body out there.

      Words sometimes have value, as hard as that might be to believe.

    2. Re:view from a linguist by mcswell · · Score: 1

      ...some of them are visible at night and it is useful to have a word that means those things, and not every little icy body out there.

      If that's the criterion, then Pluto should definitely not be called a planet, because it takes a telescope to see. (Near perihelion, an 8 inch telescope will reportedly suffice, but now that it's further out, you need at least a 10 inch, and at aphelion it will take an even larger scope.) And neither should Neptune, which is too dim to be seen with the naked eye. Uranus is reportedly visible without aid if you have good eyes and know where to look. (At least some of the ancients had the former but not the latter, so they didn't know about it.)

  38. *shrug* by aepervius · · Score: 4, Insightful

    The classification does not change anything truly, but frankly the IAU kerfuffel DOES have a point : People want to keep Pluto out of sentiment. When you point them there is then more than 100 planet to add if Pluto is a planet, THEN they go back to the "but-this-is-what-i-learnt" BS defense. The IAU definition might not be 100% good, but some of the objection to it are stupid. Like the one it does not apply to other solar system. That one is frankly stupid , change the grammar to "its star" and bam, problem solved (and frankly when I read the definition the first time I read it that way too). I think that simply a lot of people cannot emotionally let go of that pluto-named TNO and will do anything including CT about not giving credit. Pretty much avoid recognizing that Pluto as a planet was pretty damn only an accident due to detection as opposed to a real definition. Just looking at the ecliptic should give IMO a hint.

    --
    C. Sagan : A demon haunted world:
    http://www.amazon.com/gp/product/0345409469/
    visit randi.org
    1. Re:*shrug* by Wulf2k · · Score: 1

      What's wrong with having 100s of planets?

      It can be like memorizing pi. Most people learn the first few digits, and a few people can rattle it off for hours.

      "The 9 planets closest to the sun are...."

    2. Re:*shrug* by Green+Mountain+Bot · · Score: 1

      Like the one it does not apply to other solar system. That one is frankly stupid , change the grammar to "its star" and bam, problem solved (and frankly when I read the definition the first time I read it that way too).

      Which still leaves out rogue planets.

    3. Re:*shrug* by Green+Mountain+Bot · · Score: 1

      So very much this. We don't come up with arbitrary reasons to not classify new species as beetles or ants or whatever because "that would lead to too many things being called beetles". However many there are is how many there are.

    4. Re:*shrug* by david_thornley · · Score: 1

      I'd be happy with saying that there's eight major planets.

      --
      "When you have eliminated the unacceptable, whatever is left, however improbable, must be the truthiness" - Holmes
    5. Re:*shrug* by jdschulteis · · Score: 1

      Over 12,000 species of ants, over 350,000 (!) species of beetles, and many yet to be discovered.

      A few hundred planets is nothing.

  39. Breaking news!!!!!! by meglon · · Score: 1

    Some people think Pluto should still be a planet!!!!

    In other breaking news!!!!! water is wet, and the sky is blue.

    --
    Fascism: An authoritarian and nationalistic right-wing system of government and social organization. See also: NAZI's
  40. That's not what Galileo got in trouble for by NotSoHeavyD3 · · Score: 1

    What he actually got in trouble was publishing in Italian instead of Latin where he basically made a comment that was taken to be opposition to the Christian theory of the omnipotence of god. I guess I could also point out that the reason this came up was because everybody at the time was seeing that Ptolomic doesn't work but there were 2 theories, tychonic and Copernican that both work because they're mechanically equivalent. I could also point out one of the reasons the G man published in the first place was his old college buddy, the pope, asked him to. Yeah, really.

    --
    Did you know 80 to 90% of the moderators on slashdot wouldn't recognize a troll even if one dragged them under a bridge.
    1. Re:That's not what Galileo got in trouble for by Anonymous Coward · · Score: 1

      What actually got him in trouble was, after publishing he attempted to push the Church into punishing holders who supported competing theory. He then publicly insulted the Pope, who up to that time was very personally supportive of him.
      Now I agree you shouldn't be punished because you publicly insult the king, emperor, your boss, or whoever. But who actually expects that they can make their boss look like a fool and then keep their job?
      Remember Galileo's punishment was literally house arrest in a palace.
      So no he wasn't punished because his theory was against Church theology. Copernicus published on the same theory without any problem. he was just smart enough not to insult his boss in the process.

    2. Re:That's not what Galileo got in trouble for by RespekMyAthorati · · Score: 1

      Copernicus published on the same theory without any problem.

      That's because he was a Protestant!

    3. Re:That's not what Galileo got in trouble for by RockDoctor · · Score: 1

      Not as far as I can see. Though he didn't hold any significant religious office (that I can see), he spent decades as secretary to various Bishops and Prince-Bishops ; his work was presented to the Pope (and approved of). I see no evidence of him being a Protestant

      --
      Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"
  41. Re:No Fucking Shit by Aighearach · · Score: 1

    You can't contradict the poster that was on the wall during my childhood! Change is anti-science!

    ROFLCOPTER

  42. Re:Pluto is a swarf planet ! by Plus1Entropy · · Score: 1

    First of all, most planets (and former planets) were discovered before the US even existed. Most can be seen from Earth with the naked eye. So congratulations, other countries, you looked up!

    Secondly, there are 2 kinds of countries on Earth. Those that use the metric system, and those that put a person on the Moon... and landed on Mars... and sent probes to Mercury...

    --
    Only crack the nuts that crack. You don't put the ones that don't crack in the sack.
  43. Still Not a Planet, but it is a World Now by Ranger · · Score: 1

    Yes, the IAU definition is flawed, but when you look at the other characteristics of Pluto as a Trans-Neptunian Object it makes more sense. Now what has changed that since we have visited Pluto it has become a place, a world in its own right. It is no longer a faint point of light. Same goes for every other object we've visited. They have become places. Calling something a world is more metaphorical than scientific, but it satisfies that desire to elevate its status.

    --
    "You'll get nothing, and you'll like it!"
  44. Re: There's a rather important misunderstanding t by Plus1Entropy · · Score: 1

    Even if what you're saying is true, it doesn't help your argument.

    In 5 billion years the Sun will be a Red Giant. Does that mean we have to call it one right now?

    Is it possible, perhaps, that the Universe is dynamic and not static?

    --
    Only crack the nuts that crack. You don't put the ones that don't crack in the sack.
  45. People profiting from Pluto say Pluto is important by jaa101 · · Score: 1

    "Yes, Pluto Is a Planet" say people selling their new book about Pluto. And they're conveniently re-igniting the controversy at the time of publication. That seems to be the whole story. Wake me up when the IAU changes the definition again. That's likely to happen when they can form a consensus on extra-solar planets but it's unlikely to reverse the demotion of Pluto.

  46. If you want to call it a planet, call it a planet. by 91degrees · · Score: 1

    A profession that calls any element heavier than Helium a "metal" really isn't one that we should consider absolute authorities on everyday usage of English.

  47. Reinstate the asteroid planets! by Wdi · · Score: 1

    For decades, Pallas, Juno, Vesta, Ceres, Astraea, Hebe, Iris, Flora, Metis, Hygiea, Parthenope, Victoria, Egeria, Irene and Eunomia were officially classified as planets. Until a new planet definition was widely accepted in 1854. And once more, the book authors were not part of the process. Therefore, this needs to be rewound, and the planetary status voted publicly upon on Facebook!

  48. Dead language neatpicking: Hades Pluton by DrYak · · Score: 5, Informative

    Hades is the Greek god of the underworld. Pluto is the Roman version.

    And in old greek, Plouton is one of Hades' epithets - i.e.: adjectives often used together with His name to describe Him. (Just like Zeus Himself is usually "all-seeing" or the "storm gatherer", etc.)

    It means "the rich / the rich-giver", because Hades is the god of the underworld and earth itself (as opposed to Posseidon who's got the seas and Zeus who's in charge of the sky), and that's where most of mines are and on what crops grow. (Might also have been because, except for heros, most mortals - both good and bad ones - end up in Hades' realm - different sections of the underworld serve as both hell *and* heaven, unlike in christian mythology - so He ends up with the most follower).

    Over time, this has shifted to his euphemistical name (the thing mortals use to name him as to not anger Him) He became known "The Rich / The Rich Giver". (Just like in christian mythology, Satan is called often "the devil" instead of by his name).

    And then again, over time this became used as His official name. That's what the Romans eventually picked-up in Latin.

    Fun fact, the Latin "Jupiter" (in nominative case) has a similar construction : it's the contraction of "Zeus + pater" ("the father" - obviously once you look at the genealogy of most of the Greeko-Roman pantheon). But when declined in other cases, only the name is kept, e.g.: Jovis (genetive case).

    So for some period of time "Pluto" is also what the Greel go of the underworld was called,
    and even for some period of time it was His actual name.

    --
    "Sufficiently advanced satire is indistinguishable from reality." - [Tips: 1DrYakQDKCQ6y52z6QbnkxHXAocMZJE61o ]
    1. Re:Dead language neatpicking: Hades Pluton by Dragonslicer · · Score: 2

      Just like in christian mythology, Satan is called often "the devil" instead of by his name

      "Satan" isn't a name either, it's a regular noun in Hebrew, usually translated as "adversary" or "accuser". In the books of the Prophets (I don't remember offhand that it's anywhere in the Torah), the Hebrew is always "Ha-satan", "the accuser". It's just an angel that tells God how horrible humans are, playing the role of prosecutor in a trial.

    2. Re:Dead language neatpicking: Hades Pluton by BenBoy · · Score: 1

      From wikipedia, ÏÎÎá¦ÏÎÏ, ploutos, 'wealth' + ÎÏÎÏÎÏ, kratos, 'rule'. Plutocracy. â Pluto Rules!!

    3. Re:Dead language neatpicking: Hades Pluton by angel'o'sphere · · Score: 1

      (Just like in christian mythology, Satan is called often "the devil" instead of by his name).
      but Satan is not his name. His name is Lucifer. And unlike the misstranslations you see on wikipedia or (other?) christian sites, it does not mean "Light Bearer", it means "Light Bringer", or in greek: Prometheus. The god who gifted mankind fire and technology.

      --
      Cost free eBook I read (by iBook/Kobo/Amazon/ObookO/Gutenberg etc.): "The Green Odyssey" by Philip Jose Farmer.
    4. Re:Dead language neatpicking: Hades Pluton by RockDoctor · · Score: 1

      (Might also have been because, except for heros, most mortals - both good and bad ones - end up in Hades' realm - different sections of the underworld serve as both hell *and* heaven, unlike in christian mythology - so He ends up with the most follower).

      Almost all of the heroes ended up as faint, forgotten ghosts in Hades - everyone from Achilles down. Odysseus met Achilles in Hades if you remember, when Achilles lamented the pointlessness of glory and how he'd give up all his fame for a minute more life.

      From memory, the only "hero" I can remember who avoided Hades was Herakles - and that was because he was a bastard son of Zeus and got an optional promotion to godhead - which Achilles didn't.

      Oh, Tithonus didn't go to Hades either, but his claim to "hero-ness" is a bit shaky too.

      but when loathsome old age pressed full upon him, and he could not move nor lift his limbs, this seemed to her in her heart the best counsel: she laid him in a room and put to the shining doors. There he babbles endlessly, and no more has strength at all, such as once he had in his supple limbs

      --
      Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"
  49. Re: Pluto is a swarf planet ! by jd · · Score: 1

    Ceres has no active geology, Pluto does. Ceres has no core, Pluto not only does but it's liquid. Ceres is evaporating, Pluto isn't. Ceres is homogenous, Pluto is stratified. Ceres is basically a lump of rock with some ices congealed on, Pluto has liquid water. Ceres is inert, Pluto is evolving.

    Now, tell me which one best matches Earth or Mars?

    Let's see how Jupiter compares.

    Active geology? Doesn't really apply, but it is certainly active. Core? Yes. At those pressures, it's more likely liquid surrounding a solid core, which is the arrangement on Earth. It's definitely not evaporating. We've sent probes in and it's definitely stratified. It's definitely gas, liquid and solid. It's certainly evolving. What's the core size? Mass-wise, it must exceed Earth by about 1.2x. as the rocky exoplanet found of that mass is regarded as originally a Jupiter-sized gas giant that has lost its atmosphere. A similar rocky planet will exist at the heart of all gas giants.

    Conclusion, Jupiter is quite definitely a planet.

    Ok, but here we're measuring the atmosphere, as we did for Earth, as part of the size. What does this do to the diameter of Ceres? Doesn't have one, so doesn't change anything.

    What about Pluto? Pluto is the only trans-Neptunian object with a known atmosphere. (Interesting.) In some aspects it resembles even the atmosphere of Mars. (Doubly interesting. So the atmosphere closely resembles a known planet. Hmmm) New Horizons discovered in the atmosphere of Pluto a multi-layered haze, which covers the entirety of the dwarf planet and reaches altitude over 200 km. (So it's a stratified atmosphere.) The full diameter of Pluto's atmosphere, according to JPL, exceeds that of Earth, so if you are regarding atmosphere as part of the planet then Pluto is technically bigger than Earth.

    So with Pluto, we continue to have this complex, structured, organized body that could be considered larger than Earth if atmospheres are to be considered.

    I see nothing inconsistent with this model, I see plenty that allows for predictive modeling and plenty that is space and time invariant.

    --
    It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
  50. Re: There's a rather important misunderstanding t by jd · · Score: 1

    A red giant is a star that exists at point Y along the main sequence. The sun as it is now is a star that exists at point X along the main sequence.

    Astronomers with any sense call the sun a main sequence star. Everything else is ephemera.They may include that ephemera, such as element ratios, temperature, diameter, etc, because that defines where along the curve the sun is. But its core classification is invariant. And that is critical.

    The ephemera is invariant of space - it doesn't matter where the sun is, you could teleport it to the other side of the universe and it would continue to have the same element ratios, temperature and diameter. They are invariant of the observer - all observers would agree on the same values, after relativistic effects are considered.

    They are not invariant with time because they vary with time. However, and this is critical, they vary according to a clear predictive model. A model that can be falsified. A model, not to put too fine a point on it, that is actually scientific. They therefore do not vary randomly.

    Do you see how critical this is? Here, we have a classification that selects a model, and a state space that selects where we are on the model. We can then use that model to say what the next state space will be.

    How the hell are we supposed to do that with the IAU's definitions?

    According to the IAU definition, if Earth were to be launched outside of the solar system, it would be classed as a star. A brown dwarf. What the hell are we supposed to do with that? If Jupiter also did, it would also become a brown dwarf. They'd not be classed as distinct but the same. How is that useful? What model do we apply that will work for both?

    Pluto has a liquid core, has liquid water, has active geology and an atmosphere. And we're supposed to use the same model for it as we would for Ceres, which has none of those properties? How is that useful? How is that predictive?

    --
    It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
  51. Philosopher? by mschaffer · · Score: 1

    Perhaps you are thinking of Plutarch?
    https://en.wikipedia.org/wiki/...

  52. No, it's not. by lastman71 · · Score: 1

    No, it's not. Bye.

    (just a flaimbait)

  53. Re:Solution: Pluto "identifies" as a planet. by lastman71 · · Score: 1

    Nobody had made a mom joke yet? Ok: your mom identifie herself as a planet.

  54. Re: Pluto is a swarf planet ! by dryeo · · Score: 1

    https://en.wikipedia.org/wiki/...
    And also from https://en.wikipedia.org/wiki/...

    It has been suggested that a remnant layer of liquid water (or muddy ocean) may have survived to the present under a layer of ice.[7][9] Measurements taken by Dawn confirm that Ceres is both differentiated and has a shape consistent with hydrostatic equilibrium,[10] which makes Ceres the smallest object confirmed to be in hydrostatic equilibrium, being 600 km smaller than and less than half the mass of Saturn's moon Rhea, the next smallest such object.

    --
    https://en.wikipedia.org/wiki/Inverted_totalitarianism
  55. Can't fool me by SweatyStoner · · Score: 1

    People tell you the earth is flat and scientist tell you pluto isn't a planet. What's the world coming to!

  56. how about Ceres? by AlwinBarni · · Score: 1

    Maybe not everybody knows, but the story of Pluto is almost identical to Ceres, and as far as I know there was no official definition of planet before, so it is not like they "redefined", they finally created a clear definition of what planet is.

    Anyway, who cares the name in a classification, it's more important to have a logical, standardized and useful classification.

  57. definitions dynamics NOT considered harmful by epine · · Score: 1

    Too stupid for words.

    For example, it would mean that Earth was not a planet for its first 500 million years of history, because it orbited among a swarm of debris until that time, and also that if you took Earth today and moved it somewhere else, say out to the asteroid belt, it would cease being a planet.

    At that point in time, one's view of the solar system would have been that it was still a hot mess, and that certain distinguished bodies were well on the their way toward becoming planets in due time, after the gravitational wet wipe had done it's thing.

    There's nothing wrong, in principle, in using dynamical evolution as a definitional concept, even if, at certain points in time, it's somewhat forward looking.

    Maybe it's wrong here, maybe it isn't.

  58. Re:Pluto is a swarf planet ! by david_thornley · · Score: 1

    Gee! I didn't know Liberia and Myanmar had landed people on the Moon.

    --
    "When you have eliminated the unacceptable, whatever is left, however improbable, must be the truthiness" - Holmes
  59. OK so? by backslashdot · · Score: 1

    I am going to visit it on the spaceship âoeI dont give a Fuck!â

    That said, it really would be an awesome place to visit. Desolate, but awesome.

  60. Re:Solution: Pluto "identifies" as a planet. by angel'o'sphere · · Score: 1

    Hey, you got it all wrong again!
    Either it is a Planet or not. Planetoid makes no sense art all! What is next? Comet or Cometoid ... or Comatoid? Planetoid or Planetissimal? How far do you want to go! AC? Hu? Mocking us again? I know you, try your mocking game elsewhere!

    Now, come on Pluto, leave that cat alone, and don't piss at that car, the owner will shoot you, or us both!! Come on Pluto!!

    --
    Cost free eBook I read (by iBook/Kobo/Amazon/ObookO/Gutenberg etc.): "The Green Odyssey" by Philip Jose Farmer.
  61. Re: Pluto is a swarf planet ! by angel'o'sphere · · Score: 1

    Pluto is a chunk of ice.

    Earth and Mars are rocks.

    --
    Cost free eBook I read (by iBook/Kobo/Amazon/ObookO/Gutenberg etc.): "The Green Odyssey" by Philip Jose Farmer.
  62. Re:Pluto is a swarf planet ! by angel'o'sphere · · Score: 1

    And those that landed probes on Venus and probes on Asteroids.

    But no worries, there will soon be more countries doing such feats. However landing humans on Moon will likely not worthwhile during the next 50 or 100 years.

    --
    Cost free eBook I read (by iBook/Kobo/Amazon/ObookO/Gutenberg etc.): "The Green Odyssey" by Philip Jose Farmer.
  63. Re: There's a rather important misunderstanding t by mark-t · · Score: 1

    A planet of earth's size is far too tiny to qualify as any kind of brown dwarf, not even a sub brown dwarf (the lower limit for which is approximately 1 jupiter mass). No formal name has been given to such an object because none have ever been discovered. Colloquially, it is might be referred to as a rogue or interstellar planet. If we do ever discover one (and it's quite likely they exist), then I imagine the ICU will settle on a formal name at that time.

  64. Re: There's a rather important misunderstanding t by mark-t · · Score: 1

    IAU, damnit.... I saw the typo literally the very second I hit "submit".

  65. It's tiny and ..... by MerlTurkin · · Score: 1

    ....in the Kuiper belt. It's not a planet. Get over it.

  66. Oh, the gravity of the situation... by martinfb · · Score: 1

    What do we do about dwarf humans?! Are they humans?!

    Yes, of course they are humans.
    They are just not physically capable of some things that the common, regularly occurring humans can do.
    e.g. Excel at basketball -- with those regular humans.

    Seems to me that the dwarf planets are physically challenged (handicapped?) when it comes to gravity.

    --


    Self-importance and self-indulgence is the root of ALL evil.
  67. Celestial bodies must be kept in their place. by BobSteinVisiBone · · Score: 1

    Or the moons will rise up and start clearing out THEIR orbital zones.

    --
    Bob Stein, http://bobste.in
  68. Re:One of these things is not like the others by RockDoctor · · Score: 1

    Who made that list up for you? IF you tried to use it as a definition for a planet, then the proposed "Planet Nine" of Brown & Batygin 2016-01 would fail on criteria 1 and 3.

    --
    Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"
  69. Paper sources by DrYak · · Score: 1

    I've studied old greek in high school, thus a long time ago.
    Most of my sources are printed on paper (and collection dust out of my reach somewhere back at my parent's)

    As an online encyclopedia that usually is valued a lot by those who think wikipedia is utter garbage, I would point to Britanica.

    Among all the paper source I've had, the mythology books by Robert Graves were among my favorite (and will cover way much more than simple trivial elements like what are Greek god's traditional epithets).

    And you know you could use this question as an opening to go talk to that cute geeky shy girl from humanities.

    --
    "Sufficiently advanced satire is indistinguishable from reality." - [Tips: 1DrYakQDKCQ6y52z6QbnkxHXAocMZJE61o ]