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This whole section is rather misleading. It's pointless to take all these random quotes from ancient authors when the definition of planet was not a subject of dispute during this period at all. The classical definition of the seven planets was not only "not unheard of", it was the only definition of "planet" in just about every pre-modern culture. Basically, "planet" just meant "light that moves with respect to the celestial sphere". It did not have the implications of being an Earth-like body or anything of the sort.-- Pharos 11:46, 16 June 2007 (UTC)
OK, I think I've found one secondary source that seems to parallel your influence-of-astrology theory. See Alexander von Humboldt's Cosmos (section starting pg. 297). I also found something interesting on pg. 28 of Studies in Dante, which references George Cornewall Lewis's Survey of the Astronomy of the Ancients (unfortunately not online) to the point that the earlier Greeks had a different ordering of the planets, which placed the Sun and Moon in a separate "zone" closer to the Earth, rather than being separated by the orbits of Mercury and Venus (this change is actually related to the further advance of science, but who knows it may be related to the same gestalt of the influence of astrology).-- Pharos 16:04, 28 June 2007 (UTC)
OK. I've managed to locate a source that, while it doesn't refer to the dichotomy precisely (rather infuriatingly, it refers to Pliny without mentioning that Pliny states there are seven planets), does nonetheless confirm that the Greeks treated the planets differently from the Sun and the Moon. It is: The History and Practice of Ancient Astronomy by James Evans, Oxford University Press 1998, p. 296-7:
The Greeks of the seventh century BC were not even sure how many planets there were. The Greeks had two different names for Venus: it was called Hesperos [evening (star)] in its guise as evening star and Phosphoros (light bringer) when it appeared as morning star. Some asserted that Pythagoras (sixth century BC) was the first to realise that themorning and evening stars were one, while others give the credit to Parmenides (fifth century).
The Greeks considered the planets to be divine, living beings who moved by their own wills. Each planet had a proper name but was also called the star of a certain god:'
...To the early Greeks, the Sun, Moon and fixed stars were far more important than were the planets. The motion of the Sun was intimately connected with the annual cycle of agricultural labors. The phases of the Moon governed the reconing of months. And the heliacal risings and settings of the stars told the time of the year. The irregular and nonrepeating motions of the planets had no such direct utility. So it is not surprising that Hesiod's Works and Days (ca. 650 BC) which contains a good deal of practial lore about the Sun, Moon and stars, makes no mention of the planets.
Serendipodous 19:16, 16 July 2007 (UTC)
The whole “Pluto is not a planet” idea comes from reports on the IAU (International Astronomical Union) which got together and decided on a new definition of a planet ["a celestial body that (a) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (b) is in orbit around a star, and is neither a star nor a satellite of a planet”].
From this, it’s been everywhere that Pluto is not a planet. BUT on the IAU’s website, it says that Pluto IS a planet ( http://www.iau.org/iau0601_Q_A.435.0.html). Even more, it says there are 12 planets in the solar system, not 9: "Mercury, Venus, Earth, Mars, Ceres, Jupiter, Saturn, Uranus, Neptune, Pluto, Charon and 2003 UB313 (provisional name)". The last one is “popularly called Xena,” but the official name has not been chosen yet.
Pluto and Charon are classified as “Plutons,” which is a subcategory of planet, not a separate category. Plus, “Perhaps as many as a dozen or two new planets in the IAU category called “plutons” remain to be discovered” and are just waiting on reports from committees formed to study them.
The whole “Pluto isn’t a planet” might come from the IAU’s attempt to rename everything. They’ve decide that Mercury through Neptune are the first nine planets (planet 1, planet 2, etc), but Pluto is not “planet 9.” Rather, it is “Pluton 1.” —Preceding unsigned comment added by 216.138.96.227 ( talk) 18:56, 26 October 2007 (UTC)
The final resolution of August 24, 2006 did indeed include Pluto as a planet. It is clearly stated in Resolution 5A that a planet by the IAU, excluding moons and stars, is spherical by self-gravity and hydrostatic equilibrium. This definitely includes Pluto. It also uses "planet" ambiguously but corrects this in Resolution 5B. The confusion comes from people ignoring 5B. Check the IAU website. It is not old, it is current. Star Guy.
Even before I saw your response I reread both the resolutions and the Q n A page on the IAU site and you're right. The definition does not include Pluto as a planet and as you say in your Semantics section there is ambiguity and this is what is causing the confusion. Sorry about the error. I changed my website accordingly. Would you mind if I included a link for my website, astro-taxonomy.net, which has a clear and broader definition? Star Guy, Jan. 6, 2007. —Preceding unsigned comment added by Bpell ( talk • contribs) 09:26, 7 January 2008 (UTC)
That's OK then. But as I'm new to Wikipedia procedures and guidelines I might look into it to make sure. Bpell ( talk) 07:10, 9 January 2008 (UTC)
i thought charon was pluto's moon. how then is it a planet? —Preceding unsigned comment added by 69.37.164.205 ( talk) 15:32, 23 February 2008 (UTC)
This is a great article, but the lead doesn't do it justice. The current lead reads more like the lead for 2006 definition of planet, and that was what I was expecting to find in the rest of the article. I was (pleasantly) surprised: this article contains a treasure-trove of historical information. However, such surprise runs contrary to WP:LEAD, so I think the lead needs a complete rewrite. Geometry guy 18:50, 1 November 2007 (UTC)
WP:NOTDICDEF Can somebody explain the significance of this article within the scope of this rule? WP:NOTDICDEF 67.137.0.28 ( talk) 04:09, 5 May 2008 (UTC)
It doesn't just define the planet. It explains the definition and presents accompanying viewpoints,etc. I quote: "articles should begin with a definition and description of a subject" -- Jagun ( talk) 04:42, 30 May 2008 (UTC)
I am moving this comment to the talk page in case I want to figure out a way to reinsert it later. -- Kheider ( talk) 15:00, 24 July 2008 (UTC)
Even in the late 1800's astronomers had calculated that the Galilean moons were larger than our own, with one being larger than Mercury.(Recreations in Astronomy by Henry White Warren D.D. 1886)
The lead for this article is beautiful. I don't know if I have ever seen prose that great on Wikipedia. Wow. Phenomenal. Matt Yeager ♫ (Talk?) 22:51, 7 November 2008 (UTC)
I changed a description of pluto from "one sixth the size of the Earth's Moon" to "one sixth as massive as the Earth's Moon. The word "size" is tricky, since it can refer to several different properties. We should be careful to use the word "mass" when that's what we're actually talking about. In general, I avoid the word "size" in astronomy, in favor of more specific words like "radius," "diameter," "mass," "length," and so on. This article uses the word "size" a lot, and most of the uses are perfectly legitimate, since it's often making vague (but accurate) claims like "most of these objects were similar in size to Pluto." But for more specific claims, "size" should be avoided. Pluto's diameter is 70% of the Earth's Moon, but it's mass is roughly one sixth. — MiguelMunoz ( talk) 22:59, 27 November 2008 (UTC)
The intro claims that by the end of the 19th century, the working definition "only applied to objects in the Solar System." Strictly speaking, this isn't true. While the known planets were only our solar system, the term was often used when speculating about planets orbiting other stars. In that sense, it applied to undiscovered objects orbiting star. I'm giving some thought to how we might reword that sentence without making it clumsy. — MiguelMunoz ( talk) 09:14, 28 November 2008 (UTC)
Serendipodous: I have two questions:
1) Can you show me the "decree" where this definition applies only to our solar system? The cited reference is vague.
To state that the definition applies here "by decree" misses an important scientific point. If this "decree" exists and if you understood it properly, it exists only because it reflects the state of the current science. It's more important to describe the scientific reasons for the limitation, than to specify the limitation. As it stands, the current definition distinguishes planets from smaller bodies, because that's the only distinction that matters in our solar system. To state that it doesn't apply outside the solar system suggests that other definitions might rival this one, when in fact they complement this one, by distinguishing planets from larger bodies. That's the point I want to get across in this article. — MiguelMunoz ( talk) 21:37, 28 November 2008 (UTC)
2) Why did you also revert my changes regarding the use of the word "size"? Did you even read my discussion post on this question? — MiguelMunoz ( talk) 21:37, 28 November 2008 (UTC)
You've added that line about Herschel before, and it's been removed, so I don't know why this has come up again. It is inappropriate on several counts. First of all, it is unsourced; second, it uses colloquial emphasis- you make it seem like the narrator is saying, "Aww jeez! It's always a friggin comet!" Finally, it's wrong. The reason Herschel did not suspect that his object could have been another planet was simply because no one had ever found another planet before. It was as alien a concept to him as finding a second Sun would be for us. Other astronomers were actually far more eager to call it a planet than he was. Serendi pod ous 11:18, 29 November 2008 (UTC)
By the way, I have an unrelated question about Herschel. You seem to have read more on him than I have, so here goes. Once, many years ago, I read that it was actually Caroline Herschel that first spotted Uranus, but that William got the credit for the discovery by figuring out that it was a planet. However, I haven't been able to find a source for that anywhere. Have you ever read anything about Caroline Herschel's role (if any) in the discovery of Uranus? — MiguelMunoz ( talk) 11:48, 1 December 2008 (UTC)
I am sorry if I am coming across as territorial. But this is a very difficult article to maintain, because in a topic like this the difference between fact and opinion is often blurred. However, for this article to be of encyclopedic value it must remain absolutely factual. No unsourced information can be added. No opinions can be stated unless they are the opinions of notable third parties. All facts must be backed up. And I will maintain this standard ruthlessly. Serendi pod ous 11:45, 29 November 2008 (UTC)
In the section on Pluto, I found this curious sentence: the precedent set by Ceres in downgrading an object from planet to minor planet status because of a shared orbit led many to conclude that Pluto must be reclassified as well. While I was aware that people were calling for Pluto to be reclassified, I am unaware of the precedent set by Ceres playing a significant role in the downgrading. What led to the calls for reclassification were the resemblance of Pluto's size, eccentricity, and inclination to hundreds of other KBOs that had been discovered. I marked this sentence as "citation needed" for now. — MiguelMunoz ( talk) 23:16, 1 December 2008 (UTC)
![]() | This is an archive of past discussions. Do not edit the contents of this page. If you wish to start a new discussion or revive an old one, please do so on the current talk page. |
Archive 1 | ← | Archive 3 | Archive 4 | Archive 5 | Archive 6 |
This whole section is rather misleading. It's pointless to take all these random quotes from ancient authors when the definition of planet was not a subject of dispute during this period at all. The classical definition of the seven planets was not only "not unheard of", it was the only definition of "planet" in just about every pre-modern culture. Basically, "planet" just meant "light that moves with respect to the celestial sphere". It did not have the implications of being an Earth-like body or anything of the sort.-- Pharos 11:46, 16 June 2007 (UTC)
OK, I think I've found one secondary source that seems to parallel your influence-of-astrology theory. See Alexander von Humboldt's Cosmos (section starting pg. 297). I also found something interesting on pg. 28 of Studies in Dante, which references George Cornewall Lewis's Survey of the Astronomy of the Ancients (unfortunately not online) to the point that the earlier Greeks had a different ordering of the planets, which placed the Sun and Moon in a separate "zone" closer to the Earth, rather than being separated by the orbits of Mercury and Venus (this change is actually related to the further advance of science, but who knows it may be related to the same gestalt of the influence of astrology).-- Pharos 16:04, 28 June 2007 (UTC)
OK. I've managed to locate a source that, while it doesn't refer to the dichotomy precisely (rather infuriatingly, it refers to Pliny without mentioning that Pliny states there are seven planets), does nonetheless confirm that the Greeks treated the planets differently from the Sun and the Moon. It is: The History and Practice of Ancient Astronomy by James Evans, Oxford University Press 1998, p. 296-7:
The Greeks of the seventh century BC were not even sure how many planets there were. The Greeks had two different names for Venus: it was called Hesperos [evening (star)] in its guise as evening star and Phosphoros (light bringer) when it appeared as morning star. Some asserted that Pythagoras (sixth century BC) was the first to realise that themorning and evening stars were one, while others give the credit to Parmenides (fifth century).
The Greeks considered the planets to be divine, living beings who moved by their own wills. Each planet had a proper name but was also called the star of a certain god:'
...To the early Greeks, the Sun, Moon and fixed stars were far more important than were the planets. The motion of the Sun was intimately connected with the annual cycle of agricultural labors. The phases of the Moon governed the reconing of months. And the heliacal risings and settings of the stars told the time of the year. The irregular and nonrepeating motions of the planets had no such direct utility. So it is not surprising that Hesiod's Works and Days (ca. 650 BC) which contains a good deal of practial lore about the Sun, Moon and stars, makes no mention of the planets.
Serendipodous 19:16, 16 July 2007 (UTC)
The whole “Pluto is not a planet” idea comes from reports on the IAU (International Astronomical Union) which got together and decided on a new definition of a planet ["a celestial body that (a) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (b) is in orbit around a star, and is neither a star nor a satellite of a planet”].
From this, it’s been everywhere that Pluto is not a planet. BUT on the IAU’s website, it says that Pluto IS a planet ( http://www.iau.org/iau0601_Q_A.435.0.html). Even more, it says there are 12 planets in the solar system, not 9: "Mercury, Venus, Earth, Mars, Ceres, Jupiter, Saturn, Uranus, Neptune, Pluto, Charon and 2003 UB313 (provisional name)". The last one is “popularly called Xena,” but the official name has not been chosen yet.
Pluto and Charon are classified as “Plutons,” which is a subcategory of planet, not a separate category. Plus, “Perhaps as many as a dozen or two new planets in the IAU category called “plutons” remain to be discovered” and are just waiting on reports from committees formed to study them.
The whole “Pluto isn’t a planet” might come from the IAU’s attempt to rename everything. They’ve decide that Mercury through Neptune are the first nine planets (planet 1, planet 2, etc), but Pluto is not “planet 9.” Rather, it is “Pluton 1.” —Preceding unsigned comment added by 216.138.96.227 ( talk) 18:56, 26 October 2007 (UTC)
The final resolution of August 24, 2006 did indeed include Pluto as a planet. It is clearly stated in Resolution 5A that a planet by the IAU, excluding moons and stars, is spherical by self-gravity and hydrostatic equilibrium. This definitely includes Pluto. It also uses "planet" ambiguously but corrects this in Resolution 5B. The confusion comes from people ignoring 5B. Check the IAU website. It is not old, it is current. Star Guy.
Even before I saw your response I reread both the resolutions and the Q n A page on the IAU site and you're right. The definition does not include Pluto as a planet and as you say in your Semantics section there is ambiguity and this is what is causing the confusion. Sorry about the error. I changed my website accordingly. Would you mind if I included a link for my website, astro-taxonomy.net, which has a clear and broader definition? Star Guy, Jan. 6, 2007. —Preceding unsigned comment added by Bpell ( talk • contribs) 09:26, 7 January 2008 (UTC)
That's OK then. But as I'm new to Wikipedia procedures and guidelines I might look into it to make sure. Bpell ( talk) 07:10, 9 January 2008 (UTC)
i thought charon was pluto's moon. how then is it a planet? —Preceding unsigned comment added by 69.37.164.205 ( talk) 15:32, 23 February 2008 (UTC)
This is a great article, but the lead doesn't do it justice. The current lead reads more like the lead for 2006 definition of planet, and that was what I was expecting to find in the rest of the article. I was (pleasantly) surprised: this article contains a treasure-trove of historical information. However, such surprise runs contrary to WP:LEAD, so I think the lead needs a complete rewrite. Geometry guy 18:50, 1 November 2007 (UTC)
WP:NOTDICDEF Can somebody explain the significance of this article within the scope of this rule? WP:NOTDICDEF 67.137.0.28 ( talk) 04:09, 5 May 2008 (UTC)
It doesn't just define the planet. It explains the definition and presents accompanying viewpoints,etc. I quote: "articles should begin with a definition and description of a subject" -- Jagun ( talk) 04:42, 30 May 2008 (UTC)
I am moving this comment to the talk page in case I want to figure out a way to reinsert it later. -- Kheider ( talk) 15:00, 24 July 2008 (UTC)
Even in the late 1800's astronomers had calculated that the Galilean moons were larger than our own, with one being larger than Mercury.(Recreations in Astronomy by Henry White Warren D.D. 1886)
The lead for this article is beautiful. I don't know if I have ever seen prose that great on Wikipedia. Wow. Phenomenal. Matt Yeager ♫ (Talk?) 22:51, 7 November 2008 (UTC)
I changed a description of pluto from "one sixth the size of the Earth's Moon" to "one sixth as massive as the Earth's Moon. The word "size" is tricky, since it can refer to several different properties. We should be careful to use the word "mass" when that's what we're actually talking about. In general, I avoid the word "size" in astronomy, in favor of more specific words like "radius," "diameter," "mass," "length," and so on. This article uses the word "size" a lot, and most of the uses are perfectly legitimate, since it's often making vague (but accurate) claims like "most of these objects were similar in size to Pluto." But for more specific claims, "size" should be avoided. Pluto's diameter is 70% of the Earth's Moon, but it's mass is roughly one sixth. — MiguelMunoz ( talk) 22:59, 27 November 2008 (UTC)
The intro claims that by the end of the 19th century, the working definition "only applied to objects in the Solar System." Strictly speaking, this isn't true. While the known planets were only our solar system, the term was often used when speculating about planets orbiting other stars. In that sense, it applied to undiscovered objects orbiting star. I'm giving some thought to how we might reword that sentence without making it clumsy. — MiguelMunoz ( talk) 09:14, 28 November 2008 (UTC)
Serendipodous: I have two questions:
1) Can you show me the "decree" where this definition applies only to our solar system? The cited reference is vague.
To state that the definition applies here "by decree" misses an important scientific point. If this "decree" exists and if you understood it properly, it exists only because it reflects the state of the current science. It's more important to describe the scientific reasons for the limitation, than to specify the limitation. As it stands, the current definition distinguishes planets from smaller bodies, because that's the only distinction that matters in our solar system. To state that it doesn't apply outside the solar system suggests that other definitions might rival this one, when in fact they complement this one, by distinguishing planets from larger bodies. That's the point I want to get across in this article. — MiguelMunoz ( talk) 21:37, 28 November 2008 (UTC)
2) Why did you also revert my changes regarding the use of the word "size"? Did you even read my discussion post on this question? — MiguelMunoz ( talk) 21:37, 28 November 2008 (UTC)
You've added that line about Herschel before, and it's been removed, so I don't know why this has come up again. It is inappropriate on several counts. First of all, it is unsourced; second, it uses colloquial emphasis- you make it seem like the narrator is saying, "Aww jeez! It's always a friggin comet!" Finally, it's wrong. The reason Herschel did not suspect that his object could have been another planet was simply because no one had ever found another planet before. It was as alien a concept to him as finding a second Sun would be for us. Other astronomers were actually far more eager to call it a planet than he was. Serendi pod ous 11:18, 29 November 2008 (UTC)
By the way, I have an unrelated question about Herschel. You seem to have read more on him than I have, so here goes. Once, many years ago, I read that it was actually Caroline Herschel that first spotted Uranus, but that William got the credit for the discovery by figuring out that it was a planet. However, I haven't been able to find a source for that anywhere. Have you ever read anything about Caroline Herschel's role (if any) in the discovery of Uranus? — MiguelMunoz ( talk) 11:48, 1 December 2008 (UTC)
I am sorry if I am coming across as territorial. But this is a very difficult article to maintain, because in a topic like this the difference between fact and opinion is often blurred. However, for this article to be of encyclopedic value it must remain absolutely factual. No unsourced information can be added. No opinions can be stated unless they are the opinions of notable third parties. All facts must be backed up. And I will maintain this standard ruthlessly. Serendi pod ous 11:45, 29 November 2008 (UTC)
In the section on Pluto, I found this curious sentence: the precedent set by Ceres in downgrading an object from planet to minor planet status because of a shared orbit led many to conclude that Pluto must be reclassified as well. While I was aware that people were calling for Pluto to be reclassified, I am unaware of the precedent set by Ceres playing a significant role in the downgrading. What led to the calls for reclassification were the resemblance of Pluto's size, eccentricity, and inclination to hundreds of other KBOs that had been discovered. I marked this sentence as "citation needed" for now. — MiguelMunoz ( talk) 23:16, 1 December 2008 (UTC)