- Status
There were good reasons for changing Pluto's status, but after all these years of being officially classified a planet, I think Pluto should remain one; grandfathered in with an asterisk. The fact that Eris is smaller than Pluto does open the door to a discussion about it, but that's not my reason for voting "Yes".
That said, I wonder what they will call the first confirmed planetoid that is flat? :mrgreen:
That said, I wonder what they will call the first confirmed planetoid that is flat? :mrgreen:
Sycamorefan":3hvme3du said:
1. Very unlikely
2. Very very very very unlikely. Despite it's orbital period being controlled by Neptune, it will never come close.
3. yes, and a Plutino
Only thost that are large enough to have taken a spheroid shape. There are lots of asteroids in the asteroid belt but only one that is large enough to be considered a sphere, Ceres. The same is probably true in the Kuyper Belt, many objects but only a few large enough for gravity to give them a spherical shape.jsmoody2":3pa85tfs said:
Both Ceres and Pluto are dwarf planets.
The current list is: Ceres, Pluto, Haumea, Makemake, and Eris
The current list is: Ceres, Pluto, Haumea, Makemake, and Eris
Pluto was designated as a planet when Tombaugh found it. Okay now we know a lot more about the region where Pluto exists,but Pluto was already in the club,leave him there as a planet regardless of the scientific opinion. Abbott and Costello are in the baseball hall of fame,never having played a game,there is an American buried in Red Square in Moscow. Sometimes something that just does not seem right,is exactly correct,thats what makes us human,we can reason.!!!!
Ceres was designated a planet when it was first found as well, until it was realized it was but one of hundreds (now nearly a half million known) of objects in the asteroid belt. Then it was called an asteroid. Now it's been upgraded to a dwarf planet.
The same situation is now going on with KBOs and the Kuiper Belt.
And Ceres is much more dominant in the asteroid belt, having more mass than the other half a million combined.
The same situation is now going on with KBOs and the Kuiper Belt.
And Ceres is much more dominant in the asteroid belt, having more mass than the other half a million combined.
Why does it matter?
It will be the same whether it is a dwarf or a normal planet. It will not change either way. :roll:
It will be the same whether it is a dwarf or a normal planet. It will not change either way. :roll:
The choices in the poll are not worded well; since Eris is only slightly smaller than Pluto and is substantially more massive, if Pluto is a planet, then Eris is. I would be inclined to say they are both planets, though they can be put in a subcategory of planets called dwarf planets. Really the only argument against the planetary status of Pluto (and Eris) is small size/low mass. The eccentricity and inclination of their orbits is irrelevant. There are a number of extrasolar planets with orbits that are just as eccentric as Pluto's or even more so, and they are obviously planets. Composition isn't really relevant either. We may one day find a icy planet the size of Mars in an eccentric orbit far beyond Eris; would anyone argue that an object like that shouldn't be classified as a planet?
The small size of Pluto and Eris is a better reason for saying they aren't planets; their inability to "clear their orbits" is essentially a function of their small size (though the phrase itself is rather vague and should be defined more clearly -- not to mention that it seems conceivable an object as large as Mercury may someday be found that hasn't "cleared its orbit", however we define it). Pluto is obviously much smaller than a number of planetary satellites. But it's worth noting that the largest satellites (e.g., Titan and Ganymede) would certainly be classified as planets if they orbited the sun independently. Also, though Pluto and Eris are small, they are far bigger than Ceres, the largest asteroid.
The real issue is not Pluto or Eris, it is deciding on a minimum size for planets in general. I don't think the orbit should be a factor (except to say they should orbit a star independently, not a planet, except in the case of binary objects). The definition ideally would use physical factors, like the definition of a star (a body massive enough to ignite fusion of hydrogen in its core). The best I've heard is saying that anything massive enough to be in hydrostatic equilibrium (i.e., to be forced into a round shape due to its mass) is a planet. This definition would make a lot of objects planets, including Pluto, Eris, Ceres, and a few other TNOs, but at least it's based on physics, not a random attempt to draw a line to either include or not include Pluto.
The small size of Pluto and Eris is a better reason for saying they aren't planets; their inability to "clear their orbits" is essentially a function of their small size (though the phrase itself is rather vague and should be defined more clearly -- not to mention that it seems conceivable an object as large as Mercury may someday be found that hasn't "cleared its orbit", however we define it). Pluto is obviously much smaller than a number of planetary satellites. But it's worth noting that the largest satellites (e.g., Titan and Ganymede) would certainly be classified as planets if they orbited the sun independently. Also, though Pluto and Eris are small, they are far bigger than Ceres, the largest asteroid.
The real issue is not Pluto or Eris, it is deciding on a minimum size for planets in general. I don't think the orbit should be a factor (except to say they should orbit a star independently, not a planet, except in the case of binary objects). The definition ideally would use physical factors, like the definition of a star (a body massive enough to ignite fusion of hydrogen in its core). The best I've heard is saying that anything massive enough to be in hydrostatic equilibrium (i.e., to be forced into a round shape due to its mass) is a planet. This definition would make a lot of objects planets, including Pluto, Eris, Ceres, and a few other TNOs, but at least it's based on physics, not a random attempt to draw a line to either include or not include Pluto.
I thought the poll structure was very poor.
Why can't both be planets.
yes, icy ones if you like.... but not non-planet dwarf planets approved by the IAU.
Planets are pulled spherical by their own gravity,
orbit stars (and/or brown dwarfs etc)
They do not carry out fusion.
Very simple. IAU get over it.
Why can't both be planets.
yes, icy ones if you like.... but not non-planet dwarf planets approved by the IAU.
Planets are pulled spherical by their own gravity,
orbit stars (and/or brown dwarfs etc)
They do not carry out fusion.
Very simple. IAU get over it.
I think the problem is the 9 planet model is wrong in any scenario. Either there are 10-13 planets,(grouping gas giants with little planets(bizzare as can be.) or your sticking to an 8 planet model just because it's easy(grouping tiny mercury and mars with giant Jupiter. Again the clearing it's path thing is vague as on jupiter can effect half a solar system(clearing earth path for us or asteroid belt.
By your definition earth doesn't qualify as a planet since it has been said that over a thousand earths could fit inside Jupiter.Skyskimmer":38hzgpou said:
But if the current reason for having only eight planets is because school children would have a hard time memorizing 12 or 14 then I feel sorry for the next generation.
Your kinda missing my point. Earth shouldn't be compared to Jupiter but instead jupiters moons. My point is the 8 planet model meant something when we were ignorant about the galaxy, but with exo planets, and knowledge of dwarf planets/ moons it's a great deal different.bdewoody":2zj9f0qx said:
I mean just look at the historical context of mars, it's small it has no atmosphere, yet it gets mentioned more than say Io or Europa. To me this don't make a whole loft of sense. Of course I wouldn't teach children about ever 40 different objects. But I would place importance of understanding the size of jupiter and it's moon, Mercury or the outer three planets shouldn't be taught to children. It leads people with the impression that the 8 planets are all that matters which is far from the truth. I'd rather teach kids about the asteriod belts, jupiter mars and venus, leave out the dead weight. Until they take it upon themselve to learn it.
Your teaching kids to think in quantities not qualities.
Quick pop-quiz:
What does the earth orbit around? What does jupiter orbit around? What does Io orbit around?
Once you answer that, the silliness of: "Earth shouldn't be compared to Jupiter but instead jupiters moons." should be self-evident.
Now, quick, off the top of your head, name at least five hundred million stars in the order of magnitude. They're far more important than any planet. Ready? GO!
What does the earth orbit around? What does jupiter orbit around? What does Io orbit around?
Once you answer that, the silliness of: "Earth shouldn't be compared to Jupiter but instead jupiters moons." should be self-evident.
Now, quick, off the top of your head, name at least five hundred million stars in the order of magnitude. They're far more important than any planet. Ready? GO!
Pluto should remain a planet as a tribute to the classical era of planetary discovery. The work and efforts of past pioneers should be remembered for their accomplishments.
discovery in 1930 Urbain Le Verrier, Percival Lowell, William H. Pickering, Clyde Tombaugh.
“In the 1840s, using Newtonian mechanics, Urbain Le Verrier predicted the position of the then-undiscovered planet Neptune after analysing perturbations in the orbit of Uranus.[17] Subsequent observations of Neptune in the late 19th century caused astronomers to speculate that Uranus' orbit was being disturbed by another planet besides Neptune. In 1906, Percival Lowell, a wealthy Bostonian who had founded the Lowell Observatory in Flagstaff, Arizona in 1894, started an extensive project in search of a possible ninth planet (to named Pluto), which he termed "Planet X".[18]
By 1909, Lowell and William H. Pickering had suggested several possible celestial coordinates for such a planet.[19] Lowell and his observatory conducted his search until his death in 1916, but to no avail. Unbeknownst to Lowell, on March 19, 1915, his observatory had captured two faint images of Pluto, but did not recognise them for what they were.” [19][20] Due to a ten-year legal battle with Constance Lowell, Percival's widow, who attempted to wrest the observatory's million-dollar portion of his legacy for herself, the search for Planet X did not resume until 1929,[21] when its director, Vesto Melvin Slipher, summarily handed the job of locating Planet X to Clyde Tombaugh, a 23-year-old Kansas man who had just arrived at the Lowell Observatory after Slipher had been impressed by a sample of his astronomical drawings.[21]
Tombaugh's task was to systematically image the night sky in pairs of photographs taken two weeks apart, then examine each pair and determine whether any objects had shifted position. Using a machine called a blink comparator, he rapidly shifted back and forth between views of each of the plates, to create the illusion of movement of any objects that had changed position or appearance between photographs. On February 18, 1930, after nearly a year of searching, Tombaugh discovered a possible moving object on photographic plates taken on January 23 and January 29 of that year. A lesser-quality photograph taken on January 21 helped confirm the movement.[22] After the observatory obtained further confirmatory photographs, news of the discovery was telegraphed to the Harvard College Observatory on March 13, 1930.[19]”
“Neptune was mathematically predicted before it was directly observed. With a prediction by Urbain Le Verrier, telescopic observation confirming the existence of a major planet were made on the night of September 23, 1846, and into the early morning of the 24th,[1] at the Berlin Observatory, by astronomer Johann Gottfried Galle (assisted by Heinrich D'Arrest), working from Le Verrier's calculations. It was a sensational moment of 19th century science and dramatic confirmation of Newtonian gravitational theory. In François Arago's apt phrase, Le Verrier had discovered a planet "with the point of his pen."
In retrospect, after it was discovered it turned out it had been observed many times before, but not recognized, and there were others who made various calculations about its location, but did not lead to its observation. By 1846, the planet Uranus had completed nearly one full orbit since its discovery by William Herschel in 1781, and astronomers had detected a series of irregularities in its path which could not be entirely explained by Newton's law of gravitation. These irregularities could, however, be resolved if the gravity of a farther, unknown planet were disturbing its path around the Sun. In 1845, astronomers Urbain Le Verrier in Paris and John Couch Adams in Cambridge separately began calculations to determine the nature and position of such a planet. Unfortunately, Le Verrier's triumph also led to a tense international dispute over priority, as, shortly after the discovery, George Airy, at the time British Astronomer Royal, announced that Adams had also predicted the discovery of the planet.[2] Nevertheless, the Royal Society awarded Le Verrier the Copley medal in 1846 for his achievement, without mention of Adams.[3]”
“Uranus can barely be seen by the naked eye, but was much more recently discovered (1789).
Uranus is the seventh planet from the Sun, and the third-largest and fourth most massive planet in the Solar System. It is named after the ancient Greek deity of the sky Uranus (Ancient Greek: Οὐρανός) the father of Cronus (Saturn) and grandfather of Zeus (Jupiter). Though it is visible to the naked eye like the five classical planets, it was never recognized as a planet by ancient observers because of its dimness and slow orbit.[16] Sir William Herschel announced its discovery on March 13, 1781, expanding the known boundaries of the Solar System for the first time in modern history. Uranus was also the first planet discovered with a telescope.”
1 ^ a b c d Kollerstrom, N. (2001). "A Neptune Discovery Chronology". The British Case for Co-prediction. University College London. http://web.archive.org/web/200511190317 ... /chron.htm. Retrieved 2007-08-23.
2. ^ a b Danjon, Prof. André (Director of the Paris Observatory) (1946). "Le centenaire de la découverte de Neptune". (in French) Ciel et Terre (journal) (1946) vol.62, p.369. (unknown, France). http://adsabs.harvard.edu/abs/1946C%26T....62..369D. Retrieved 2008-01-23.
2 ^ a b c d e f g h i Hutchins, R. (2004). "Adams, John Couch (1819–1892)". Oxford Dictionary of National Biography (Oxford University Press). http://www.oxforddnb.com/view/article/123.
16. ^ "MIRA's Field Trips to the Stars Internet Education Program". Monterey Institute for Research in Astronomy. http://www.mira.org/fts0/planets/101/text/txt001x.htm. Retrieved 2007-08-27.
17. ^ K. Croswell (1997). Planet Quest: The Epic Discovery of Alien Solar Systems. The Free Press. pp. 43. ISBN 978-0684832524.
18. ^ Tombaugh, C. W. (1946). "The Search for the Ninth Planet, Pluto". Astronomical Society of the Pacific Leaflets 5: 73–80. Bibcode: 1946ASPL....5...73T.
19 ^ a b c W. G. Hoyt (1976). "W. H. Pickering's Planetary Predictions and the Discovery of Pluto". Isis 67 (4): 551–564.. doi:10.1086/351668. http://links.jstor.org/sici?sici=0021-1753(197612)67%3A4%3C551%3AWHPPPA%3E2.0.CO%3B2-I. Retrieved 2007-06-27.
20 ^ Mark Littman (1990). Planets Beyond: Discovering the Outer Solar System. Wiley. pp. 70. ISBN 047151053X.
21 ^ a b Croswell, p. 50
22 ^ Croswell p. 52
(Lowell Observatory Archives)
(Lowell observatory, Flagstaff, Arizona)
Article http://en.wikipedia.org/wiki/Discovery_of_Neptune retrieved 11/19/10
article http://en.wikipedia.org/wiki/Pluto#Name retrieved 11/19/10
article http://en.wikipedia.org/wiki/Uranus retrieved 11/19/20
discovery in 1930 Urbain Le Verrier, Percival Lowell, William H. Pickering, Clyde Tombaugh.
“In the 1840s, using Newtonian mechanics, Urbain Le Verrier predicted the position of the then-undiscovered planet Neptune after analysing perturbations in the orbit of Uranus.[17] Subsequent observations of Neptune in the late 19th century caused astronomers to speculate that Uranus' orbit was being disturbed by another planet besides Neptune. In 1906, Percival Lowell, a wealthy Bostonian who had founded the Lowell Observatory in Flagstaff, Arizona in 1894, started an extensive project in search of a possible ninth planet (to named Pluto), which he termed "Planet X".[18]
By 1909, Lowell and William H. Pickering had suggested several possible celestial coordinates for such a planet.[19] Lowell and his observatory conducted his search until his death in 1916, but to no avail. Unbeknownst to Lowell, on March 19, 1915, his observatory had captured two faint images of Pluto, but did not recognise them for what they were.” [19][20] Due to a ten-year legal battle with Constance Lowell, Percival's widow, who attempted to wrest the observatory's million-dollar portion of his legacy for herself, the search for Planet X did not resume until 1929,[21] when its director, Vesto Melvin Slipher, summarily handed the job of locating Planet X to Clyde Tombaugh, a 23-year-old Kansas man who had just arrived at the Lowell Observatory after Slipher had been impressed by a sample of his astronomical drawings.[21]
Tombaugh's task was to systematically image the night sky in pairs of photographs taken two weeks apart, then examine each pair and determine whether any objects had shifted position. Using a machine called a blink comparator, he rapidly shifted back and forth between views of each of the plates, to create the illusion of movement of any objects that had changed position or appearance between photographs. On February 18, 1930, after nearly a year of searching, Tombaugh discovered a possible moving object on photographic plates taken on January 23 and January 29 of that year. A lesser-quality photograph taken on January 21 helped confirm the movement.[22] After the observatory obtained further confirmatory photographs, news of the discovery was telegraphed to the Harvard College Observatory on March 13, 1930.[19]”
“Neptune was mathematically predicted before it was directly observed. With a prediction by Urbain Le Verrier, telescopic observation confirming the existence of a major planet were made on the night of September 23, 1846, and into the early morning of the 24th,[1] at the Berlin Observatory, by astronomer Johann Gottfried Galle (assisted by Heinrich D'Arrest), working from Le Verrier's calculations. It was a sensational moment of 19th century science and dramatic confirmation of Newtonian gravitational theory. In François Arago's apt phrase, Le Verrier had discovered a planet "with the point of his pen."
In retrospect, after it was discovered it turned out it had been observed many times before, but not recognized, and there were others who made various calculations about its location, but did not lead to its observation. By 1846, the planet Uranus had completed nearly one full orbit since its discovery by William Herschel in 1781, and astronomers had detected a series of irregularities in its path which could not be entirely explained by Newton's law of gravitation. These irregularities could, however, be resolved if the gravity of a farther, unknown planet were disturbing its path around the Sun. In 1845, astronomers Urbain Le Verrier in Paris and John Couch Adams in Cambridge separately began calculations to determine the nature and position of such a planet. Unfortunately, Le Verrier's triumph also led to a tense international dispute over priority, as, shortly after the discovery, George Airy, at the time British Astronomer Royal, announced that Adams had also predicted the discovery of the planet.[2] Nevertheless, the Royal Society awarded Le Verrier the Copley medal in 1846 for his achievement, without mention of Adams.[3]”
“Uranus can barely be seen by the naked eye, but was much more recently discovered (1789).
Uranus is the seventh planet from the Sun, and the third-largest and fourth most massive planet in the Solar System. It is named after the ancient Greek deity of the sky Uranus (Ancient Greek: Οὐρανός) the father of Cronus (Saturn) and grandfather of Zeus (Jupiter). Though it is visible to the naked eye like the five classical planets, it was never recognized as a planet by ancient observers because of its dimness and slow orbit.[16] Sir William Herschel announced its discovery on March 13, 1781, expanding the known boundaries of the Solar System for the first time in modern history. Uranus was also the first planet discovered with a telescope.”
1 ^ a b c d Kollerstrom, N. (2001). "A Neptune Discovery Chronology". The British Case for Co-prediction. University College London. http://web.archive.org/web/200511190317 ... /chron.htm. Retrieved 2007-08-23.
2. ^ a b Danjon, Prof. André (Director of the Paris Observatory) (1946). "Le centenaire de la découverte de Neptune". (in French) Ciel et Terre (journal) (1946) vol.62, p.369. (unknown, France). http://adsabs.harvard.edu/abs/1946C%26T....62..369D. Retrieved 2008-01-23.
2 ^ a b c d e f g h i Hutchins, R. (2004). "Adams, John Couch (1819–1892)". Oxford Dictionary of National Biography (Oxford University Press). http://www.oxforddnb.com/view/article/123.
16. ^ "MIRA's Field Trips to the Stars Internet Education Program". Monterey Institute for Research in Astronomy. http://www.mira.org/fts0/planets/101/text/txt001x.htm. Retrieved 2007-08-27.
17. ^ K. Croswell (1997). Planet Quest: The Epic Discovery of Alien Solar Systems. The Free Press. pp. 43. ISBN 978-0684832524.
18. ^ Tombaugh, C. W. (1946). "The Search for the Ninth Planet, Pluto". Astronomical Society of the Pacific Leaflets 5: 73–80. Bibcode: 1946ASPL....5...73T.
19 ^ a b c W. G. Hoyt (1976). "W. H. Pickering's Planetary Predictions and the Discovery of Pluto". Isis 67 (4): 551–564.. doi:10.1086/351668. http://links.jstor.org/sici?sici=0021-1753(197612)67%3A4%3C551%3AWHPPPA%3E2.0.CO%3B2-I. Retrieved 2007-06-27.
20 ^ Mark Littman (1990). Planets Beyond: Discovering the Outer Solar System. Wiley. pp. 70. ISBN 047151053X.
21 ^ a b Croswell, p. 50
22 ^ Croswell p. 52
(Lowell Observatory Archives)
(Lowell observatory, Flagstaff, Arizona)
Article http://en.wikipedia.org/wiki/Discovery_of_Neptune retrieved 11/19/10
article http://en.wikipedia.org/wiki/Pluto#Name retrieved 11/19/10
article http://en.wikipedia.org/wiki/Uranus retrieved 11/19/20
I did vote for calling Pluto a planet, but not because of it's size.
I did it because of it's history. I do not think that the word "planet" must be used just because of a size - I think we could use it for historical reasons as well. I am used to think about Pluto as a planet - and so do all kinds of books, encyclopedias and other writings. I like Pluto as planet. We could include in definition a distance from Sun - but it's not needed.
I think that Pluto should be scientifically classified as needed, but in common language, it should remain a planet. I don't know if I feel it because of nostalgia or for any other reason ..basically, I do not see any strong reason to have a strong classification of planets. For all other stars - yes. But our solar system has a history ..after all - there are probably many star systems, where you could consider if earth-sized object is a planet or a tiny dwarf.
We have a lot of literacy, very good science fiction, where Pluto is spoken about as a planet ..well, scientific discovery could be that Earth is not flat, but this is not a scientific discovery that Pluto is not a planet. This is rather a linguistic question. And, in language, it is.
I bring an example. For a long time, scientists tried, for whatever reason, to classify humans as animals - where actual definition of animal rather includes that it's non-human species of such kind - like a "fellow" is close to me, but not me. Lately, as it has been literally impossible to make humans really think that human is an animal, language-makers have made a suggestion to not use that word in English about humans, because language rather is what it is and words have meanings based on how they are used and understood, not based on some normalized logic.
If I look this Eris ..I really don't have any ties with it and if it is a dwarf planet, be it. But about Pluto - I have, actually, a deep connection with this planet and if it's degraded, I feel somewhat like if something has been taken away from my personal myth about solar system - look at this list and think if you want to make it outdated for no reason. Do you want to make a book outdated if it actually contains no factual bias, just you have some urge to redefine some word used in it? I do not. I believe that language is not weakened if it contains an exception.
So I rather suggest this kind of wording:
planet - list of planets as-is, closed.
dwarf planet - list of small planets, including Pluto.
strict planet - list of big planets whenever it's needed.
I did it because of it's history. I do not think that the word "planet" must be used just because of a size - I think we could use it for historical reasons as well. I am used to think about Pluto as a planet - and so do all kinds of books, encyclopedias and other writings. I like Pluto as planet. We could include in definition a distance from Sun - but it's not needed.
I think that Pluto should be scientifically classified as needed, but in common language, it should remain a planet. I don't know if I feel it because of nostalgia or for any other reason ..basically, I do not see any strong reason to have a strong classification of planets. For all other stars - yes. But our solar system has a history ..after all - there are probably many star systems, where you could consider if earth-sized object is a planet or a tiny dwarf.
We have a lot of literacy, very good science fiction, where Pluto is spoken about as a planet ..well, scientific discovery could be that Earth is not flat, but this is not a scientific discovery that Pluto is not a planet. This is rather a linguistic question. And, in language, it is.
I bring an example. For a long time, scientists tried, for whatever reason, to classify humans as animals - where actual definition of animal rather includes that it's non-human species of such kind - like a "fellow" is close to me, but not me. Lately, as it has been literally impossible to make humans really think that human is an animal, language-makers have made a suggestion to not use that word in English about humans, because language rather is what it is and words have meanings based on how they are used and understood, not based on some normalized logic.
If I look this Eris ..I really don't have any ties with it and if it is a dwarf planet, be it. But about Pluto - I have, actually, a deep connection with this planet and if it's degraded, I feel somewhat like if something has been taken away from my personal myth about solar system - look at this list and think if you want to make it outdated for no reason. Do you want to make a book outdated if it actually contains no factual bias, just you have some urge to redefine some word used in it? I do not. I believe that language is not weakened if it contains an exception.
So I rather suggest this kind of wording:
planet - list of planets as-is, closed.
dwarf planet - list of small planets, including Pluto.
strict planet - list of big planets whenever it's needed.
ricx":15fg66i2 said:
Yes, orbit as factor would make Earth a space-ship if humankind is going to take it from collapsing Sun one day and carry to some other star. But why not?
Anyway, reading your text I got another feeling - why not to use a common sense to say if something is a planet or not, until we eventually find some underlying rule behind this common sense? For example, for small objects we would call them planets in case we can create an Earth-like ecosystem there (so that people living there might be happier, for example, but just because they will feel planets), whereas bone-shaped object in space is obviously not planet. Planet-sized human-made object would be artificial planet (as there are artificial islands) and objects, which once rotated around stars, are more easily called planets than those, which just travel around cosmos. And a star rotating around other star is obviously not a planet, but some hot objects might be. Also, earth-sized moons of large planets are moons, so if Earth will eventually become moon of other planet ..I think it would be still called a planet, because of it's history, even if definition of planet has changed a lot and it would become moon even in today's language. Anyway, if we start calling something a moon and find out that it was once a planet, we would still stick to the word. And so on and so on. Right now it's obvious that we should close the list of planets as we might start finding more and more small objects until nearly no-one remembers the full list - but it's easy to remember Pluto for anyone, who knows all planets. And the funny story that there are dwarfs bigger than planet ..this, actually, makes science only more interesting, if we can point to such nuances and oddities
Like having a particle with odd name etc.Trying to make out a science from classifying objects in common language ..I think it's bad, non-informative kind of science. That is - if someone finds a new planet from some distant star, we all understand even now, which kind of object this is, approximately. We are not having any kind of problem with words as they are right now - and having some non-planet, which is larger than smallest known planet ..this would only make it clearer to children at schools that this word really does not point to objectively different class of things
So - let's let a language develop on it's own. Scientific language can always invent new words, prefixes and classifiers to make things more exact; common language does not need this kind of exactness, but rather it relies on history and how people feel about the world around them.
This debate is a hot topic, but it is up to the IAU to decide, so we just have to wait for there desision.
Poll is misleading. Pluto lost its planet status not because of its or Erins size but because it doesn't dominate its orbital space. This requirement have been inserted in IAU planet definition for specific purpose of eliminating any chance for planet status of any object beyond Neptune orbit. Not only that Earth wouldn't classify as a planet if inserted in orbit beyond the Pluto, but not even a Jupiter sized object would. As orbits get more distant from the Sun even a giant planet can't dominate other objects along ever widening swatch of space covered by its orbit.
I say definition of a planet should be simplified (hence including Pluto, Erin and many other objects): object that is not a star, primarily orbits a star and is spherical in shape. Everything else is irrelevant (but could be used for planetary classification).
I say definition of a planet should be simplified (hence including Pluto, Erin and many other objects): object that is not a star, primarily orbits a star and is spherical in shape. Everything else is irrelevant (but could be used for planetary classification).
Come on ... why all these discussions? It's so simple. I have 12 animals in my house! Are they all dogs? No! I have 4 hamsters ( maybe 8 now ), 4 fishes and 4 birds. So, let's make it simple. We have a lot of different bodies in the solar system. Some of these bodies are comets, some are asteroids, some are rocky earth-like plantes, some are gas giant planets, some are rocky dwarf planets, some are moons and some are "I don't know what else we may have out there". So what's the issue? Afraid of saying a cat is not a dog? Afraid of saying an Eagle is not a Hummingbird?
), 4 fishes and 4 birds. So, let's make it simple. We have a lot of different bodies in the solar system. Some of these bodies are comets, some are asteroids, some are rocky earth-like plantes, some are gas giant planets, some are rocky dwarf planets, some are moons and some are "I don't know what else we may have out there". So what's the issue? Afraid of saying a cat is not a dog? Afraid of saying an Eagle is not a Hummingbird?I'm always for a constant examination and re-examination of evidence as new information comes to light. Unfortunately, I feel that Ceres, Pluto, Eris et al have been subjected to classification where empahsis was put on 'dwarf' instead of 'planet'. :ugeek:
I'll still and always consider to be a 'planet' (whatever that means nowadays), but one where it's admittedly small and composed (from what's known of it thus far) of various ices. Similarly this case also applies to Eris. In that regard, I call them ice-dwarf planets. Still planets, mind you, but just small ones composed of ice. Ceres, however, is mainly rocky instead of icy, so it's a rock-dwarf planet.
In any case, for me at least, emphasis is on PLANET, be it icy, rocky, or who knows what other kind of materials the universe can dream up.
I'll still and always consider to be a 'planet' (whatever that means nowadays), but one where it's admittedly small and composed (from what's known of it thus far) of various ices. Similarly this case also applies to Eris. In that regard, I call them ice-dwarf planets. Still planets, mind you, but just small ones composed of ice. Ceres, however, is mainly rocky instead of icy, so it's a rock-dwarf planet.
In any case, for me at least, emphasis is on PLANET, be it icy, rocky, or who knows what other kind of materials the universe can dream up.
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