Page 6 of 6 FirstFirst ... 456
Results 151 to 176 of 176

Thread: Pluto is a planet

  1. #151
    Join Date
    May 2003
    Posts
    5,777
    Quote Originally Posted by DonM435 View Post
    Cadmium a transition metal? This has ruined my day!
    Don't be ridiculous. Of course Cadmium is a transition metal! How could anyone think otherwise? Oh, wait, sorry, Swift.
    Conserve energy. Commute with the Hamiltonian.

  2. #152
    Join Date
    Apr 2007
    Location
    Nowhere (middle)
    Posts
    34,604
    My two cents: If schools are going to teach that Pluto is not a planet, then they should teach students about all the known dwarf planets as well.
    "I'm planning to live forever. So far, that's working perfectly." Steven Wright

  3. #153
    Quote Originally Posted by Ken G View Post
    That's more or less the system already in place, where we have 8 "major planets" in the solar system, and Pluto is a "minor planet." Where the IAU gets into a rub is when it refuses to let both major and minor planets be categories of "planet". It simply makes no sense to me to say that only major planets are planets, when planetologists are going to study both types, and in their internal communications they are always going to use the term "planet" for Pluto. Even moons are in some important sense planets, as they will be studied by similar means and comparisons between moons and Mercury are not at all uncommon. So the bottom line is, in the field of planetology, all these things are "planets", so what the IAU wants to officially designate a planet is more an issue in elementary school classrooms, where everything must be packaged in black and white for eight year olds, than it is for the field of astronomy, where professional researchers are more able to function in an environment of nuance.
    Yes, it's a tweak more than a revolution, but that's all it needs.

  4. #154
    Quote Originally Posted by speach View Post
    This fascinates me, why do people get so upset about the status of Pluto? It's really neither here nor there whether we call it a planet or not. Would it make one jot of difference to the object what we call it, it's still a sphere (ok not a perfect sphere) of rock, ice and a little gas.
    Thank Walt Disney. It's the price we pay for humanising (dogifying) a planet. Benefits include life long interest in astronomy nurtured by dopey but lovable dog. Pluto may be dopey but he is no dwarf - any 10 year old knows that!

  5. #155
    Join Date
    Jun 2003
    Location
    Central Florida.
    Posts
    5,320
    Quote Originally Posted by Canis Lupus View Post
    Thank Walt Disney. It's the price we pay for humanising (dogifying) a planet. Benefits include life long interest in astronomy nurtured by dopey but lovable dog. Pluto may be dopey but he is no dwarf - any 10 year old knows that!
    You must not remember back when Planet Goofy was demoted . . .

  6. #156
    Join Date
    Oct 2001
    Location
    The Space Coast
    Posts
    3,973
    Quote Originally Posted by Noclevername View Post
    My two cents: If schools are going to teach that Pluto is not a planet, then they should teach students about all the known dwarf planets as well.
    Yes. They probably should. And probably are. Any discussion of Pluto would almost have to include the class of objects it is a family member of (not "dwarf planets" which is not the best category to use): Kuiper Belt objects. Or Plutoids. Or TNOs. Whatever you want to call them, Pluto and it's siblings (Eris, Orcus, Makemake, etc.) are all important and hold clues to our Solar System's origin and evolution.

    It's more instructive and descriptive to put Pluto where it belongs than to tack it on to the "major" planets. Is there ample argument that there should be further divisions (Gas/Ice Giant, Terrestrial)? Sure. I think there's probably more similarities than we think for some of the giant planets vs. terrestrial than there are between the "biggies" and the Kuiper Belt, but I'm not a planetary scientist.

    Where I get hung up is that by putting Pluto and Ceres (for example) in the same class (dwarf planets) it could imply that something is similar about them besides their size, and I think that's a mistake. On the one hand, I like the appeal of the geophysical definitions, because they tell us more about what the objects are and how they formed. I am quite resistant to include (most) moons in that, however, for the same reasons.

    CJSF
    "A scientific theory
    Isn't just a hunch or guess
    It's more like a question
    That's been put through a lot of tests
    And when a theory emerges
    Consistent with the facts
    The proof is with science
    The truth is with science"
    -They Might Be Giants, "Science Is Real"


    lonelybirder.org

  7. #157
    Join Date
    Apr 2007
    Location
    Nowhere (middle)
    Posts
    34,604
    Quote Originally Posted by CJSF View Post
    Yes. They probably should. And probably are.
    To my knowledge, at least all the ones I know of are not. They teach planets, and the rest are afterthoughts.
    "I'm planning to live forever. So far, that's working perfectly." Steven Wright

  8. #158
    Join Date
    Oct 2001
    Location
    The Space Coast
    Posts
    3,973
    Huh. The people I've spoken with around here say the opposite. Same with family in MA. Must differ from place to place.

    CJSF
    "A scientific theory
    Isn't just a hunch or guess
    It's more like a question
    That's been put through a lot of tests
    And when a theory emerges
    Consistent with the facts
    The proof is with science
    The truth is with science"
    -They Might Be Giants, "Science Is Real"


    lonelybirder.org

  9. #159
    Join Date
    Dec 2006
    Posts
    2,221
    Quote Originally Posted by Noclevername View Post
    My two cents: If schools are going to teach that Pluto is not a planet, then they should teach students about all the known dwarf planets as well.
    You only have to do that for the kids who first learned that Pluto was a planet. For the youngest crowd, you just never mention Pluto in the first place, at least not any more than you'd mention Ceres.

  10. #160
    Join Date
    Feb 2003
    Location
    Depew, NY
    Posts
    10,597
    Quote Originally Posted by Noclevername View Post
    My two cents: If schools are going to teach that Pluto is not a planet, then they should teach students about all the known dwarf planets as well.
    I had a lesson plan for that. It blended nicely with the expanding community unit: Family - Community - City - State - Nation - World. Week two, Major planets. Week 3, everything else. Not too much detail as it was a highly vocational, special education classroom.
    Solfe, Dominus Maris Pavos.

  11. #161
    Quote Originally Posted by DonM435 View Post
    You must not remember back when Planet Goofy was demoted . . .
    My therapist says much the same thing. He specialises in PTS.

    It didn't help matters the other day with him when I said all the planets should be named after dogs - Goofy for Neptune, Lassie for Jupiter, Toto for Mercury, Rin Tin Tin for Mars and Snoopy for the Moon. Tried hard to fit the Littlest Hobo in there somewhere, but concluded it could be saved for recent discoveries. Earth would be Wolf.

    He terminated the session at this point.
    Last edited by Canis Lupus; 2017-Apr-07 at 12:42 AM.

  12. #162
    Join Date
    Oct 2001
    Location
    The Space Coast
    Posts
    3,973
    Quote Originally Posted by Amber Robot View Post
    You only have to do that for the kids who first learned that Pluto was a planet. For the youngest crowd, you just never mention Pluto in the first place, at least not any more than you'd mention Ceres.
    No no. I think is is precisely wrong! Pluto is important in that it is the first Kuiper Belt/TNO or whatever discovered. The fact that "we" did reclassify it is itself an important learning tool! Your suggested approach makes it exactly what the IAU detractors say it does! And that's not true. Or at least shouldn't be.

    CJSF
    "A scientific theory
    Isn't just a hunch or guess
    It's more like a question
    That's been put through a lot of tests
    And when a theory emerges
    Consistent with the facts
    The proof is with science
    The truth is with science"
    -They Might Be Giants, "Science Is Real"


    lonelybirder.org

  13. #163
    Join Date
    Apr 2007
    Location
    Nowhere (middle)
    Posts
    34,604
    Quote Originally Posted by CJSF View Post
    Huh. The people I've spoken with around here say the opposite. Same with family in MA. Must differ from place to place.

    CJSF
    I'm in Indiana, kind of infamous for "de-emphasizing" science that conflicts with Biblical cosmology. Among our other current infamousnesses.
    "I'm planning to live forever. So far, that's working perfectly." Steven Wright

  14. #164
    Join Date
    Feb 2003
    Location
    Depew, NY
    Posts
    10,597
    My son went to a religious school for 2 years before it closed due to consolidation with another school. When they closed, they took the kids to the library and told them they could take home any books they wanted. My son walked out with every book that had pictures of planets. He had a rather comprehensive collection of children's books on the solar system. Maybe 20 to 30 titles.

    Of course, there is a twist. About 5 or 6 years later, a new school bought the property and I started working there. My son felt that these books were now too childish and wanted to get rid of them. I ended up donating to the library at work. I also purchased Cosmos and Pluto Files to add to his donation. Funny how that worked out.
    Solfe, Dominus Maris Pavos.

  15. #165
    Join Date
    Sep 2003
    Posts
    11,793
    Quote Originally Posted by Ken G View Post
    All the same, if you look at the current IAU definition of "planet", a dwarf planet is not a planet, as according to your link:
    "By the end of the Prague General Assembly, its members voted that the resolution B5 on the definition of a planet in the Solar System would be as follows:
    A celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighbourhood around its orbit.)" Note that also ducks the issue of what should count as a planet in other solar systems, so we're left to wonder if Pluto would be a planet if it orbited some other star!
    I see your point, but they had the sense to add the "dwarf planet" definition as well. From the whole of B5 there is more to the story:

    (1) A planet is a celestial body that
    (a) is in orbit around the Sun,
    (b) has sufficient mass for its self-gravity to overcome rigid body forces
    so that it assumes a hydrostatic equilibrium (nearly round) shape,
    and
    (c) has cleared the neighbourhood around its orbit.

    (2) A "dwarf planet" is a celestial body that
    (a) is in orbit around the Sun,
    (b) has sufficient mass for its self-gravity to overcome rigid body forces
    so that it assumes a hydrostatic equilibrium (nearly round) shape2,
    (c) has not cleared the neighbourhood around its orbit, and
    (d)is not a satellite.

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


    So it looks like any object, new or old, would get a label, not that others wouldn't be used (e.g. asteroids).
    Last edited by George; 2017-Apr-13 at 03:01 PM. Reason: removed footnote numbers
    We know time flies, we just can't see its wings.

  16. #166
    Quote Originally Posted by Canis Lupus View Post
    If we assume that Pluto is a different type of planet - something I have problems seeing at the moment - much of this mess could have been avoided if a better naming system was used. My suggestion is using these classes: Planet, 1st degree Planet, 2nd degree Planet. (I'll leave off 3rd degree Planet for the time being for reasons to be explained later perhaps.)

    Pluto has the distinction of being a first declared first degree Planet - what a total honour - it's almost like an honour crowning an honour! Nothing second rate about Pluto!

    There are other first degree planets also, which have led to the idea of Pluto being an "1DP".

    Where then do we turn to for our 2DP? The moons. Then we become blessed with a second degree planet in our visual midst - a little like the scenes in Star Wars? How romantic and beautiful was that?

    All positive, everyone is a winner.

    "Moon" can be redefined and still remain useful - perhaps the LOCAL second degree planet of any planet you happen to be on. That way, all second degree planets are still moons by reference to the local higher degree planet. Therefore, still no losers. Our second degree Planet is still a moon, or the Moon while still being a type of planet also.

    Most importantly, this system is geometrically sound because there is a degree change between planet/first degree and second degree planets.
    The thing I forgot to mention in the above is the "potatoes out soccer-balls in" rule.

  17. #167
    Join Date
    Mar 2007
    Location
    Falls Church, VA (near Washington, DC)
    Posts
    7,605
    In the new Universe Today article about New Horizons, the author referred to Pluto as a planet, with no adjective.

  18. #168
    Join Date
    Mar 2004
    Posts
    1,165
    Quote Originally Posted by Amber Robot View Post
    You only have to do that for the kids who first learned that Pluto was a planet. For the youngest crowd, you just never mention Pluto in the first place, at least not any more than you'd mention Ceres.
    I teach in a planetarium, and I can tell you that children's favorite "planet" is still Pluto, even though most of them weren't alive or old enough to remember when it was a planet. (10 years and counting!) I wouldn't dare not mentioning Pluto in a show about the solar system, and if you are going to tell the story of its classification you have to also include Ceres. I love talking about this topic with students, especially having a great planetarium software that can visualize of 1000's of Kuiper belt objects in 3D. It becomes a lesson on the process of science, not just throwing facts about the solar system at the children to memorize.

  19. #169
    Join Date
    Sep 2003
    Posts
    11,793
    Quote Originally Posted by pumpkinpie View Post
    I teach in a planetarium, and I can tell you that children's favorite "planet" is still Pluto, even though most of them weren't alive or old enough to remember when it was a planet. (10 years and counting!) I wouldn't dare not mentioning Pluto in a show about the solar system, and if you are going to tell the story of its classification you have to also include Ceres. I love talking about this topic with students, especially having a great planetarium software that can visualize of 1000's of Kuiper belt objects in 3D. It becomes a lesson on the process of science, not just throwing facts about the solar system at the children to memorize.
    Excellent! You're making wonderful lemonade from a single lemon. They probably had no idea that astronomers have been through the naming game before, giving us asteroids. Pluto's eccentric behavior, along with hundreds of its closest friends, is another segway to the hypothetical Planet 9.
    We know time flies, we just can't see its wings.

  20. #170
    Join Date
    Sep 2003
    Posts
    11,793
    Quote Originally Posted by Hornblower View Post
    In the new Universe Today article about New Horizons, the author referred to Pluto as a planet, with no adjective.
    That may be out of respect for those with New Horizons, which began when Pluto was a planet.
    We know time flies, we just can't see its wings.

  21. #171
    Join Date
    May 2007
    Location
    Earth
    Posts
    9,775
    Quote Originally Posted by Ken G View Post
    That's more or less the system already in place, where we have 8 "major planets" in the solar system, and Pluto is a "minor planet." Where the IAU gets into a rub is when it refuses to let both major and minor planets be categories of "planet". It simply makes no sense to me to say that only major planets are planets, when planetologists are going to study both types, and in their internal communications they are always going to use the term "planet" for Pluto. Even moons are in some important sense planets, as they will be studied by similar means and comparisons between moons and Mercury are not at all uncommon. So the bottom line is, in the field of planetology, all these things are "planets", so what the IAU wants to officially designate a planet is more an issue in elementary school classrooms, where everything must be packaged in black and white for eight year olds, than it is for the field of astronomy, where professional researchers are more able to function in an environment of nuance.
    The IAU definition has "planet" and "dwarf planet" being completely disjoint sets. This is unlike their treatment of "planet" and "gas giant [planet]," where the latter is a proper subset of the former. This is in vivid contrast to how the modifier "dwarf" is used in other contexts outside of astronomy: a dwarf fruit tree is still a fruit tree, and a dwarf beagle is still a beagle, and even inside astronomy, where a red dwarf [star] is still a star.

    Information about American English usage here and here. Floating point issues? Please read this before posting.

    How do things fly? This explains it all.

    Actually they can't: "Heavier-than-air flying machines are impossible." - Lord Kelvin, president, Royal Society, 1895.



  22. #172
    Join Date
    Mar 2004
    Posts
    1,165
    Quote Originally Posted by swampyankee View Post
    The IAU definition has "planet" and "dwarf planet" being completely disjoint sets. This is unlike their treatment of "planet" and "gas giant [planet]," where the latter is a proper subset of the former. This is in vivid contrast to how the modifier "dwarf" is used in other contexts outside of astronomy: a dwarf fruit tree is still a fruit tree, and a dwarf beagle is still a beagle, and even inside astronomy, where a red dwarf [star] is still a star.
    I agree. An idea I had at one point was "Kuiperoids." Asteroids are in the asteroid belt....Kuiperoids are in the Kuiper belt. Ceres is a big and round asteroid. Pluto is a big and round Kuiperoid.

    But nobody asked me.....

  23. #173
    Join Date
    Mar 2007
    Location
    Falls Church, VA (near Washington, DC)
    Posts
    7,605
    Quote Originally Posted by pumpkinpie View Post
    I teach in a planetarium, and I can tell you that children's favorite "planet" is still Pluto, even though most of them weren't alive or old enough to remember when it was a planet. (10 years and counting!) I wouldn't dare not mentioning Pluto in a show about the solar system, and if you are going to tell the story of its classification you have to also include Ceres. I love talking about this topic with students, especially having a great planetarium software that can visualize of 1000's of Kuiper belt objects in 3D. It becomes a lesson on the process of science, not just throwing facts about the solar system at the children to memorize.
    That looks like science presentation at its best to our children. Keep up the good work.

  24. #174
    Join Date
    Dec 2006
    Posts
    2,221
    Quote Originally Posted by CJSF View Post
    No no. I think is is precisely wrong! Pluto is important in that it is the first Kuiper Belt/TNO or whatever discovered. The fact that "we" did reclassify it is itself an important learning tool! Your suggested approach makes it exactly what the IAU detractors say it does! And that's not true. Or at least shouldn't be.

    CJSF
    What I meant was not to mention it as a planet. When I was young and learned about the asteroid belt, it wasn't mentioned that Ceres was once considered a planet. I'm not saying don't teach about Pluto at all, just teach about it as a KBO.

  25. #175
    Join Date
    Sep 2003
    Posts
    11,793
    Quote Originally Posted by swampyankee View Post
    The IAU definition has "planet" and "dwarf planet" being completely disjoint sets. This is unlike their treatment of "planet" and "gas giant [planet]," where the latter is a proper subset of the former. This is in vivid contrast to how the modifier "dwarf" is used in other contexts outside of astronomy: a dwarf fruit tree is still a fruit tree,...
    But if dendrologists were (assuming they haven't) to define the differences between the two trees, would it necessarily mean that the dwarf fruit tree therefore no longer be a fruit tree? It would, I suppose, depend on the way the definition is made. It could be done either way.

    A dwarf person is a person who happens to be less than 4'-10" in height. Had they stated that "a dwarf planet is a planet that cannot clear its orbit", would that work? If so, can we not imply it and use it as such? It's not an easy question for me to answer, admittedly.


    ... and even inside astronomy, where a red dwarf [star] is still a star.
    Yet a white dwarf is not a star. The lack of fusion is a major problem for a white dwarf to be considered to be a star, but no so of any definition for a red dwarf. Similarly, it seems like orbital clearing could be interpreted either way. The hard core version would be one where the "lack of clearing", like fusion is for a star, eliminates a dwarf planet from being a subgroup. But a soft core version is that "lack of clearing" better defines it as a dwarf, similar to your dwarf tree and dog examples.

    The IAU's answer to the number of planets question seems to take the soft core approach.
    Last edited by George; 2017-Apr-13 at 06:08 PM.
    We know time flies, we just can't see its wings.

  26. #176
    Join Date
    May 2007
    Location
    Earth
    Posts
    9,775
    Quote Originally Posted by George View Post
    But if dendrologists were (assuming they haven't) to define the differences between the two trees, would it necessarily mean that the dwarf fruit tree therefore no longer be a fruit tree? It would, I suppose, depend on the way the definition is made. It could be done either way.

    A dwarf person is a person who happens to be less than 4'-10" in height. Had they stated that "a dwarf planet is a planet that cannot clear its orbit", would that work? If so, can we not imply it and use it as such? It's not an easy question for me to answer, admittedly.


    Yet a white dwarf is not a star. The lack of fusion is a major problem for a white dwarf to be considered to be a star, but no so of any definition for a red dwarf. Similarly, it seems like orbital clearing could be interpreted either way. The hard core version would be one where the "lack of clearing", like fusion is for a star, eliminates a dwarf planet from being a subgroup. But a soft core version is that "lack of clearing" better defines it as a dwarf, similar to your dwarf tree and dog examples.

    The IAU's answer to the number of planets question seems to take the soft core approach.
    Neglecting the language issue, a definition where a body's categorization is location dependent is, in my opinion, intrinsically flawed.

    Information about American English usage here and here. Floating point issues? Please read this before posting.

    How do things fly? This explains it all.

    Actually they can't: "Heavier-than-air flying machines are impossible." - Lord Kelvin, president, Royal Society, 1895.



Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •