Talk:Magnetosphere of Jupiter/Archive 1

Merge discussion

• oppose The magnetosphere article is going to get a lot more technical and detailed, and th Jupiter article is large enough without adding more content. Graeme Bartlett (talk) 02:29, 8 August 2008 (UTC)

GAN?

If you guys are done adding info for now, and you don't really have time to bulk it up to FA-level, I suggest submitting this to GAN so we can get the Jupiter topic set up. Nergaal (talk) 17:31, 11 March 2009 (UTC)

It's not nearly ready yet. I'll be getting to it over the weekend. Serendi^podous 17:44, 11 March 2009 (UTC)

I am going to expand it soon. Ruslik (talk) 19:57, 11 March 2009 (UTC)

Unclear and hard

I think that Wikipedia is mostly for normal people, not for experts. So, for example, why temperatures are expressed in electronvolts? A people who isn't a physician will have some problems in understanding this article, so technical e too hard. I can understand it, of course, but it's tough. Moreover, I think that the section "Structure" looks like a comparison between a normal magnetic field (or the Earth's one) and Jupiter's one. Please consider the ipothesis to make this article less hard. :-) --Roberto Segnali all'Indiano 17:40, 18 April 2009 (UTC)

Nerd city, needs rewrite

The best articles (of this type) are the ones that can present the information clearly - without condescending - while at the same time maintain technical relevance. Otherwise the reader will not learn (at which point why bother). Write for your audience, not for the choir who probably already know this content. —Preceding unsigned comment added by 75.90.145.126 (talk) 04:14, 15 December 2009 (UTC)

I'm not sure it's possible to describe this in layman's terms, because there really aren't any. There's nothing in magnetospherics that has any bearing on everyday life, so it's difficult, if not impossible, to describe it in everyday terms. I'm a layman, and I nearly had an aneurysm trying to get to grips with researching this material.Serendi^podous 16:20, 15 December 2009 (UTC)

Comments from Cryptic C62

Here are some comments:

Comments regarding lead paragraph which has been substantially rewritten

"The magnetosphere of Jupiter is the largest and most powerful of any planet's in the Solar System." Slightly awkward phrasing. Suggestion: "The magnetosphere of Jupiter is the largest and most powerful magnetosphere of any planet in the Solar System. "Spanning several tens of Jupiter radii in its forward direction, and extending almost to the orbit of Saturn in its trailing direction, Jupiter's magnetic field is the largest structure in the Solar System not tied to the Sun." Yikes, this is only the second sentence and it's already more technical than what most readers will be able to deal with. "Spanning several tens of Jupiter radii" could be rewritten as "Spanning more than 20/30/whatever times the radius of Jupiter". What does "forward direction" mean? And "trailing direction"? "not tied to the sun" What exactly is meant by "tied"? Perhaps this is some sort of astronomical term I've never heard of, but it seems to be unencyclopedic to me. Better, but still includes the odd phrase "spanning several tens of Jupiter radii". At no point is it made explicitly clear that "magnetosphere of Jupiter" and "Jupiter's magnetic field" are the same thing. Serendipodous and I fixed everything except At no point is it made explicitly clear that "magnetosphere of Jupiter" and "Jupiter's magnetic field" are the same thing. They are actually not the same thing. Ruslik_Zero 09:46, 5 June 2009 (UTC) At no point is it made explicitly clear that they are different either. The relation between the two needs to be made clearer. --Cryptic C62 · Talk 19:48, 5 June 2009 (UTC) I rewrote the first paragraph of the lead. Ruslik_Zero 20:33, 5 June 2009 (UTC) "If one could see the magnetic field from Earth, it would appear five times larger than the full moon in the sky despite its far greater distance." I haven't even read the article yet, but I'm fairly certain that it does not spend its entirety discussing how large the magnetosphere is. Nor should the lead. Besides, this sentence is useless trivia at best. "Jupiter's magnetic field was first inferred from observations of radio emissions..." Hrmm. I'm fairly certain that the existence of Jupiter's field was inferred, not the field itself. Suggestion: "The existence Jupiter's magnetic field was first inferred from observations of radio emissions..." "Wider and flatter than the Earth's magnetic field, Jupiter's is stronger by an order of magnitude." Some readers might see these two clauses as being cause-and-effect, which I don't think is the case here. I suggest moving the shape bit into the previous paragraph (which dealt with the size of the field). It is in a better place now, but the phrasing still implies cause-and-effect. Suggested rewrite: "Jupiter's magnetic field is wider and flatter than the Earth's magnetic field. Jupiter's is also stronger by an order of magnitude." or some such. See above. Ruslik_Zero 20:33, 5 June 2009 (UTC)

• "Jupiter has a strong internally generated magnetic field, which excludes the Solar wind from a cavity around the planet called the magnetosphere of Jupiter." If it is possible, I would recommend rearranging this sentence to move the title closer to the beginning. Something like "The magnetosphere of Jupiter is a cavity around Jupiter which is excluded from Solar wind by the planet's strong magnetic field".

  Rewritten by Serendipodous. Ruslik_Zero 13:38, 7 June 2009 (UTC)

• "Spanning several tens of Jupiter radii in the Sun's direction, and extending almost to the orbit of Saturn in the opposite direction" These two indirect measurements are not helpful for readers who are not already familiar with the size of the solar system. Hard numbers would be better.

  I do not think that if a reader does not understand the basic structure of the Solar System, hard numbers will be helpful either. After all, 1 billion km is unlikely to tell the reader anything useful. Ruslik_Zero 13:38, 7 June 2009 (UTC)

  Fair enough. "Spanning several tens of Jupiter radii" is still an awkward wording. "Tens" is not an often-used word, nor will all readers be familiar with the concept of using a planetary body's radius as a unit of measurement, especially since that radius has yet been defined in the article. --Cryptic C62 · Talk 22:19, 7 June 2009 (UTC)

  Changed to "a few million kilometers". Ruslik_Zero 07:24, 8 June 2009 (UTC)

• "Since then, seven additional spacecraft have studied the magnetosphere of Jupiter." This statement will age quickly, and it is possible that there were some spacecraft which gathered data on the magnetosphere but were not specifically designed/launched for that purpose. Suggest replacing "seven" with "several".

  I actually disagree that this statement will age quickly. The last spacecraft that visited Jupiter was New Horizons in 2007. The next will be Juno in 2016 (mentioned in the last section). After that Europa Orbiter may arrive around 2030. Ruslik_Zero 13:38, 7 June 2009 (UTC)

• "The internal field is generated by eddy currents in Jupiter's outer core, which is composed of metallic hydrogen." What is an "internal field"? The infobox wikilinks the term to dipole, which doesn't really help. What is an "eddy current"?
• "Volcanic eruptions on Jupiter's moon Io eject large amounts of sulfur dioxide gas into Jupiter's ionosphere" Is there a more general alternative to "ionosphere"? Ionosphere of Jupiter does not exist, and Ionosphere is written entirely about Earth.
• "Forced to co–rotate with Jupiter, the torus's plasma loads and stretches the Jovian magnetic field, forming a structure called a magnetodisk" What is co-rotation? What does it mean to "load and stretch" the magnetic field? What is a magnetodisk?

  The removal of "co-" doesn't really help, since the phrase "Forced to rotate with the planet" is equally ambiguous. Forced to rotate in the same direction? At the same speed? The parenthetical explanation of "Jovian" is both awkward and grammatically incorrect. Suggest either linking to the wiktionary entry on Jovian or just sticking with "Jupiter's" throughout the lead to avoid confusion. The meaning of "loads and stretches" is still unclear.

  Rewritten by Serendipodous. Ruslik_Zero 13:38, 7 June 2009 (UTC)

  "The torus is locked in step with Jupiter's rotation," is even less helpful. What does "locked in step" mean? I was not under the impression that this was an article about dancing. Also, is "loads" the correct scientific term here? Its meaning is not clear. Perhaps "fills" ? --Cryptic C62 · Talk 22:19, 7 June 2009 (UTC)

I think you're being excessively pedantic here. The only way to explain this the way you're demanding is to waste an extra sentence explaining that it orbits with Jupiter's speed and direction. And in truth I don't really understand why anyone would have had trouble with "co-rotation" in the first place. It's pretty self-explanatory. And yes, "load" is a common term used by scientists to describe the deposition of plasma into a magnetic field. Serendi^podous 06:35, 8 June 2009 (UTC)

Self-explanatory to you, perhaps. I prefer precise and encyclopedic. Suggested rewrite: "The torus rotates with the same speed and direction as Jupiter's rotation". Is there a Jovian equivalent of geostationary orbit? --Cryptic C62 · Talk 22:58, 8 June 2009 (UTC)

Geostationary orbit has to do with gravity. This is electromagnetism. Serendi^podous 09:11, 9 June 2009 (UTC)

OK. Revised. Serendi^podous 08:51, 11 June 2009 (UTC)

• "which effectively make Jupiter a tiny radio pulsar." The first sentence of pulsar explicitly defines a pulsar as being a star, which Jupiter is not. I suggest the implementation of a comparative phrase such as "which give Jupiter the appearance of being" or "which make Jupiter similar to". Also, "tiny" is unencyclopedic. How about "small" or "miniscule"?

  "Minuscule" refers to the physical size. However Jupiter is much larger than a typical pulsar. "Small" is misleading since Jupiter is nor small, it is very, very ... small pulsar. So I do not know any good synonym. Ruslik_Zero 13:38, 7 June 2009 (UTC)

  Well, rephrased this sentence. Ruslik_Zero 13:47, 7 June 2009 (UTC)

  Much better. --Cryptic C62 · Talk 22:19, 7 June 2009 (UTC)

• "Jupiter's aurorae have been observed in all parts of the electromagnetic spectrum including X-rays" Any particular reason why only x-rays are mentioned? If there is no reason, I suggest either removing the "including" bit altogether or expanding it to include other wavelengths.

  Jupiter is the only planet that has X-ray bright aurorae. Other planets emit many orders of magnitude less X-rays. I added mid infrared though. Ruslik_Zero 13:38, 7 June 2009 (UTC)

  The first version said "all parts of the electromagnetic spectrum." This version says "all parts of the electromagnetic spectrum from mid infrared to X-ray." These are substantially different claims. Which is correct? --Cryptic C62 · Talk 22:19, 7 June 2009 (UTC)

  Fixed. Ruslik_Zero 07:20, 8 June 2009 (UTC)

• "The interaction of energetic particles with the surfaces of Jupiter's largest moons markedly affects their chemical and physical properties, and it both affects and is affected by the particular motions in its tenuous planetary ring system." This sentence makes sense up until "and it both affects...". What does "it" refer to? The interaction, or the energetic particles themselves. Suggest splitting off into a new sentence and expanding (if necessary) for clarity. What is meant by "particular motions"? If "planetary ring system" refers to what I assume it refers to, perhaps it should have a link to Rings of Jupiter.

  Fixed by Serendipodous. Ruslik_Zero 07:20, 8 June 2009 (UTC)

• "Radiation belts represent a significant hazard for spacecraft and humans." I believe "represent" should be "present". Hazard for humans? I was unaware that humans had visited Jupiter. If this is actually discussed in the literature (which I presume is not the case), suggest rewriting to "Radiation belts represent a significant hazard for spacecraft and, potentially, humans." If this is not discussed in the literature or if it doesn't seem that important, I would suggest dropping the human bit and possibly expanding on the spacecraft hazards bit.

  Fixed by Serendipodous. Ruslik_Zero 07:20, 8 June 2009 (UTC)

• Backtracking: "Its existence was first inferred from observations of radio emissions" The meaning of "it" is ambiguous due to the preceding sentences. Does "it" refer to the magnetosphere? Or the magnetic field?

  Fixed. Ruslik_Zero 09:22, 9 June 2009 (UTC)

• There are, among others, three chunks of information available in this article: the discovery of the magnetosphere, the exploration thereof, and the hazards associated with such an exploration. I think it is far less likely that someone will search this article in hopes of finding information about the hazards the magnetosphere posed for previous spacecraft than that someone will search this article in hopes of finding a history of the research done on the magnetosphere. Although I haven't read either section carefully yet, I suggest merging Discovery with Exploration and radiation hazards into a History section (or some similar name). How silly would it be if Gamma-ray burst's History section had been broken up into a stubby Discovery and a much longer The difficulties of studying GRBs? Quite silly. *time warp* After having read through Discovery, I am again convinced of the logicality of the proposed merger, as Discovery deals with much more than just the discovery of the magnetosphere.

  The last section is not only about history. It is also about future. In addition, it is a tradition to have two separate sections about Discovery and Exploration in Solar System articles (see Uranus). Ruslik_Zero 09:22, 9 June 2009 (UTC)

  Regarding your first argument, in my experience, it is not uncommon for history sections to discuss current and planned developments. Regarding the second, Britannica had a long tradition of successfully producing and selling expensive paper encyclopedias before a man named Jimbo Wales came along. The point I'm making is that adhering to tradition is not a valid argument. Regardless, I see that Serendipodous has merged the sections in question. Struck. --Cryptic C62 · Talk 17:21, 9 June 2009 (UTC)

  Unfortunately in the current form this section will be difficult for understanding. Will readers understand such sentences as: "Voyager 1 was the first probe which encountered the Io plasma torus, and Voyager 2 discovered the current sheet in the equatorial plane."? They are not supposed to know what current sheet and Io plasma torus are. All this is explained in the following sections. So, the most reasonable position for the exploration section is at the end of an article. (And traditions are more important than your think because they are often based on past experience.) Ruslik_Zero 19:06, 9 June 2009 (UTC)

  It seems that this is something you should discuss with Serendipodous. Partial rewrite? Move to bottom of article? --Cryptic C62 · Talk 21:19, 9 June 2009 (UTC)

• "(decametric radio emission—DAM)" Why is "decametric radio emission" shorted to "DAM"? according to decameter, "dam" is an abbreviation for decameter. Why would the abbreviation for the unit also be the abbreviation for the radio emission?

  That's the standard. It's nothing to do with us. Those are the abbreviations used by the scientists who study Jupiter. Serendi^podous 09:15, 9 June 2009 (UTC)

  DecAMetric radio emission. Ruslik_Zero 09:22, 9 June 2009 (UTC)

  Very weird. Struck. --Cryptic C62 · Talk 17:21, 9 June 2009 (UTC)

• "1 millitesla (T) (10 Gauss (G))" It is unclear why these units are both spelled out and abbreviated. Neither is used again in this section.

  Because they're mentioned again in the article. Serendi^podous 09:15, 9 June 2009 (UTC)

  I removed them. Ruslik_Zero 09:22, 9 June 2009 (UTC)

• "led to the discovery Jovian decimetric radiation (DIM)" missing "of" between "discovery" and "Jovian"? The same question that I asked regarding DAM applies to DIM as well.

  Fixed (of). DecIMetric radio emission. Ruslik_Zero 09:22, 9 June 2009 (UTC)

• "led to improved values for the magnetic field strength" Which were...? Also, suggest changing "values" to "estimates". No value is better than any other. Only estimates can improve.

  Fixed. Ruslik_Zero 09:22, 9 June 2009 (UTC)

  What were those estimates? Earlier estimates were provided earlier in the paragraph. It would be helpful to include these improved estimates as a point of comparison. --Cryptic C62 · Talk 17:21, 9 June 2009 (UTC)

  It will require me witting a 10 kb long section. Ruslik_Zero 18:36, 9 June 2009 (UTC)

  I find that hard to believe. How is it that you were able to give the first estimate ("astronomers concluded that Jupiter possesses a magnetic field with a strength of about 1 millitesla (10 Gauss)") in one sentence but the second would take 10 kb? --Cryptic C62 · Talk 21:19, 9 June 2009 (UTC)

  There is no a single number that I can put here. All estimates were model dependent. 10 Gauss was just an educated guess (maximum cyclotron frequency). Ruslik_Zero 13:28, 10 June 2009 (UTC)

  Perhaps you could offer the highest and lowest estimates as a range and make it clearer that the first estimate (10 gauss) was just a ballpark guess. Alternatively, you could mention that the estimates were model-dependent and just provide the estimates for 2 or 3 of the most notable models. --Cryptic C62 · Talk 16:26, 10 June 2009 (UTC)

  I found some estimates and included them. Ruslik_Zero 13:41, 17 June 2009 (UTC)

• "The modulation of Jupiter's DAM emissions" This sentence suffers from RAS syndrome. Suggest removing "emissions".

  Fixed. Ruslik_Zero 09:22, 9 June 2009 (UTC)

• "The definitive discovery of the Jovian magnetic field occurred in December 1973, when Pioneer 10 spacecraft flew near the planet." First, I suggest either adding a "the" before "Pioneer 10" or removing the word "spacecraft". Second, what did Pioneer 10 do to definitively discover the magnetic field? If I throw a tennis ball over the spot where a dinosaur died, that doesn't imply that I've definitively discovered a dinosaur fossil.

  The field was directly measured by the magnetometer of Pioneer 10. Ruslik_Zero 09:23, 9 June 2009 (UTC)

  Then perhaps the article should mention that: "The definitive discovery of the Jovian magnetic field occurred in December 1973, when the Pioneer 10 spacecraft, equipped with a magnetometer, flew near the planet."

  It was not the only device on board of Pioneer. Should I also mentioned that it carried Plasma Analyzer, Charged Particle Instrument, Cosmic Ray Telescope, etc? They also contributed to the discovery of the magnetosphere. Ruslik_Zero 18:36, 9 June 2009 (UTC)

  Yes, I think the article should make mention of at least a few of the important instruments involved in the discovery. I also think that this task will be made easier by splitting the Pioneer 10 sentence up into 2 or 3 sentences. --Cryptic C62 · Talk 21:19, 9 June 2009 (UTC)

  I added a note. Ruslik_Zero 13:28, 10 June 2009 (UTC)

I'm going to skip over the rest of the Discovery and Exploration section for now, as it does not yet seem clear what the final solution for that will be. Moving on to Structure.

The only problem is the definitions introduced in the section, and since each of the concepts defined in that section is also defined elsewhere, it doesn't really matter where it is, so I'm moving it to the bottom, where I think it fits better. Serendi^podous 17:46, 10 June 2009 (UTC)

• "Jupiter's magnetosphere is a complex structure including bow shock, magnetopause, magnetotail, magnetodisk and other components" Unless bow shock is a mass noun, I believe this sentence should include "a" after "including".

Fixed. Serendi^podous 17:26, 10 June 2009 (UTC)

• "The magnetic field inside the magnetosphere emanates from a number of different sources." As this is written, it implies that there is a magnetic field outside the magnetosphere which emanates from distinct sources from the intramagnetospheric field. Is this true? Perhaps it would be simpler to write "Jupiter's magnetic field emanates..."

  Technically the field outside the magnetosphere is interplanetary (or Solar) field, but I changed the wording. Ruslik_Zero 11:57, 11 June 2009 (UTC)

• What sorts of currents are being referred to in this paragraph?

  Electrical currents. Ruslik_Zero 11:57, 11 June 2009 (UTC)

  The article should specify that. --Cryptic C62 · Talk 16:24, 12 June 2009 (UTC)

• "though they are at least 10 times weaker than the dipole" I have always loathed constructions such as "10 times weaker" or "3 times smaller". While they may make sense to the lay reader, they are fundamentally nonsensical from a mathematical standpoint. Suggested rewrite: "though they have less than one-tenth the strength of the dipole" or "though the dipole is more then 10 times stronger than any of these" or some such.
• "and its magnetic moment 18,000 times larger" Should probably contain "about" or "approximately" before 18,000, yes?

Fixed. Twice. Serendi^podous 08:49, 14 June 2009 (UTC)

• "Jupiter's magnetic field rotates at the same speed as its interior" It is not clear what "its interior" refers to.
• "with a rotation period of 9 h 55 m, and is remarkably stable; no changes in its strength or structure.." Suggested rewrite: "with a rotation period of 9 h 55 m. No changes in the magnetic field's strength or structure..." This is clearer and avoids "remarkably".
• Note 3: "For instance, the azimuthal orientation of the dipole changed by less than 0.01°" This directly contradicts the previous sentence. Suggest either removing this or rewriting the previous sentence to say "very little change" rather than "no changes". Also, what is "azimuthal orientation"?

  I do not understand this comment, there is no contradiction. Ruslik_Zero 12:20, 13 June 2009 (UTC)

  The contradiction is this: Note 3 states that there was a change in the magnetic field. A very small change, but a change nonetheless. The sentence to which Note 3 is appended states that no changes have been detected. --Cryptic C62 · Talk 03:22, 15 June 2009 (UTC)

  Note 3 only states "less than 0.01%", which means the upper limit for any change. Ruslik_Zero 13:41, 17 June 2009 (UTC)

• "Hardly any changes" is not very encyclopedic. How about "Very few changes" or "Very minute changes"?

Fixed. Serendi^podous 08:59, 14 June 2009 (UTC)

• "composed of a plasma very different from that of the solar wind." Different how?

  All article is about it. Ruslik_Zero 12:20, 13 June 2009 (UTC)

• "If one could see the magnetic field from Earth, it would appear five times larger than the full moon in the sky despite being nearly 1700 times farther away" This sentence, besides being useless trivia, interrupts two sentences which discuss the interaction of the magnetic field with the solar wind plasma. Suggest either moving it or removing it entirely.
• "the subsolar point—the point at which the Sun appears directly overhead" This description of the subsolar point is informal and somewhat misleading, as it implies that humans have stood on Jupiter and looked up at the sun. Perhaps this should mention a line from the center of the sun to the center of Jupiter or use a diagram to help visualize it.
• "In front of the magnetopause (at a distance of about 84 Rj from the planet)" First, does "from the planet" mean "from the planet's center" or "from the planet's surface"? Second, this is extremely confusing in either case because a previous sentence described the magnetopause as being 45 to 100 R_j from the planet. If 45, then the bow shock would be closer to the sun than the magnetopause. If 100, then the bow shock would be closer to Jupiter than the magnetopause. As such, the meaning of "in front of the magnetopause" is unclear.

  Fixed. Ruslik_Zero 13:41, 17 June 2009 (UTC)

• "The Jovian magnetosphere is so large that the Sun and its visible corona would fit inside it with room to spare" This is another bit of useless trivia which does not belong in this paragraph.

  I strongly object to your trivializing of important statements. Ruslik_Zero 17:50, 13 June 2009 (UTC)

More to come. --Cryptic C62 · Talk 22:40, 3 June 2009 (UTC)

Resolved, I think. Serendi^podous 07:11, 13 June 2009 (UTC)

I hate to be a bother, but would you mind providing individual replies to each concern stating what you've done to address them? It can sometimes be hard to figure out exactly what has been done without some kind of hint. Thanks mates. --Cryptic C62 · Talk 03:22, 15 June 2009 (UTC)

I was referring to the bits you've now crossed out. Serendi^podous 06:58, 15 June 2009 (UTC)

The FAC has ended. Leave me a message on my talk page if you'd like to continue with this review. --Cryptic C62 · Talk 05:25, 17 June 2009 (UTC)

Factual error

The first sentence of the article used to read "The magnetosphere of Jupiter is the cavity created in the solar wind by the planet's magnetic field." which is just flat out wrong. I've edited the lead (essentially copying the first sentence from Magnetosphere#Earth's magnetosphere), so the immediate problem is at least mitigated. Who shepherded this article to FA status, and who promoted it? A cursory review of our own article on Magnetosphere should have helped anyone here prevent this from happening in the first place.
— V = I * R (talk to Ω) 18:01, 15 December 2009 (UTC)

I reverted the change. The term "cavity" is correct. See, for instance, Blanc et al 2005, p. 227: The term ‘magnetosphere’ has first been used for the cavity in the magnetized solar wind plasma which is created by the dipolar terrestrial magnetic field.. The term "cavity" is also used in Russell, 1993. Ruslik_Zero 19:31, 15 December 2009 (UTC)

Uh... seriously? "The magnetosphere is a cavity"? I think that I see what you're getting at by quoting the above, but... to be frank, you're not comprehending what you're reading properly. The cavity is a side effect of the formation of the magnetosphere, it's not the magnetosphere itself. If you're going to own this yourself, don't take my word for it, please go and talk to someone whom you trust that knows the subject. Skimming through the talk page above I see that this was already touched upon by others, and you seem to have dismissed them as well. Don't you think that is worth checking in to?
— V = I * R (talk to Ω) 21:26, 15 December 2009 (UTC)

you're not comprehending what you're reading properly I would dispute who of us does not understand what he reads. As to the text that you wrote, it is not a definition at all, but an explanation of why the magnetosphere (i.e. the cavity) has this particular shape. Ruslik_Zero 11:52, 16 December 2009 (UTC)

Ruslik, not even the source your quoting above is supporting the sentence that you're defending. A Magnetosphere is not a cavity. It creates a cavity (out of the solar wind), certainly, but that doesn't mean that it is a cavity. Read Magnetosphere. Better yet, as I suggested above, find someone that you trust that you know has credentials to look over the sentence.
— V = I * R (talk to Ω) 14:15, 16 December 2009 (UTC)

From your first reply, it seems as though the inclusion of the word "cavity" is what is important here. With that in mind, would you be OK with: "The magnetosphere of Jupiter is the region which is created by the planet's magnetic field, which creates a cavity in the solar wind." ?
— V = I * R (talk to Ω) 14:18, 16 December 2009 (UTC)

I do not understand how magnetosphere can create a cavity? Magnetosphere is a region of space filled with hot low density plasma, it can not create anything. This region of space, because it is empty as compared the magnetosheath, is often called a cavity (i.e. empty space). How the quote does not support my definition? It more or less directly says that Earth's magnetosphere is a cavity in the solar wind!? Ruslik_Zero 14:42, 16 December 2009 (UTC)

The cavity is a side effect though, not the primary effect. The medium of the solar system is the plasma created by the suns magnetosphere (essentially), which is called the solar wind. Several planets which create magnetic fields themselves, including Jupiter and Earth, create their own local plasma field within the suns solar wind. This creates cavities in the solar wind, but the cavity itself is there because of the planet's magnetosphere, it's not what causes the magnetosphere to be. Here's an analogy: think of the environment of the solar system to be a flowing river. Each planet which has a magnetic field is a hose which is dunked in the water, pointed upstream. The magnetosphere around each hose nozzle is created by the water coming from the hose, which creates a cavity in the river water. It's a cause and effect issues.
— V = I * R (talk to Ω) 14:52, 16 December 2009 (UTC)

I may be wrong but I think it's the magnetic field, not the magnetosphere, that creates the cavity. Serendi^podous 14:59, 16 December 2009 (UTC)

Well yea... if you turn off the magnetic field then the magnetosphere goes away and the solar wind comes "roaring" in (thereby closing most of the cavity in the solar wind, although the body of the planet itself creates one as well). The thing is, the magnetic field creates a plasma (charged particles); it's the plasma that is the magnetosphere. The regen of the charged particles, caused by the magnetic field, is what creates the magnetosphere. The magnetosphere is there because it's constantly replenished after being blown away by the solar wind. Does that make sense?
— V = I * R (talk to Ω) 15:08, 16 December 2009 (UTC)

Sorry, I will be blunt, that does not make sense. I am not aware of any process by which "the magnetic field can create plasma". Plasma in Earth's the magnetosphere comes from two different sources: solar wind and ionosphere. The magnetic field creates nothing. As to definitions, in this ref on page 65 you can read The Earth's magnetosphere is the cavity carved in the solar wind by the geomagnetic field, in this ref you can find Jupiter's magnetosphere is the cavity surrounding the planet which contains and is controlled by Jupiter's magnetic fieldand in this book on page 86 you can see The magnetosphere is a cavity carved out in the solar wind flow. You can find more if you want. This definition is quite common. Ruslik_Zero 19:38, 16 December 2009 (UTC)

It makes perfect sense to what I've been taught and have read... here: Plasma, Magnetosphere, Magnetic field... heck, even Magnetosphere of Jupiter#Dynamics does a good job explaining things. I'm really uncertain where the mix up is, exactly. The only point that I'm trying to get across is that a Magnetosphere is not a cavity. It creates a cavity in the solar wind, but it's a structure all on it's own.

This whole conflict is just... strange. How about getting a third party opinion in here? One of us could post a message on Wikipedia talk:WikiProject Physics, and or the talk pages I linked to above.
— V = I * R (talk to Ω) 21:24, 16 December 2009 (UTC)

Note the difference in structure of the sentence you quoted from here: "The Earth's magnetosphere is the cavity carved in the solar wind by the geomagnetic field" It's the cavity carved in, it's not a cavity itself.
— V = I * R (talk to Ω) 21:35, 16 December 2009 (UTC)

Even I don't think that made sense. What's the difference between "the cavity created in the solar wind" and "the cavity carved in the solar wind"? Just slightly different verbs. Serendi^podous 22:02, 16 December 2009 (UTC)

←The word "Created", obviously. I'm realizing today that this is less a factual issue then a language issue, so I'll gladly take the bullet for framing this discussion incorrectly. The use of the work "created" implies causation that just isn't correct, however. At least, I think that it's the use of the word "created" that is strange... the objection is more about the sentence structure then the content, though. Verbs make a difference.
— V = I * R (talk to Ω) 22:12, 16 December 2009 (UTC)

Yes, there is a causation. The geomagnetic field (or Jovian field) excludes solar wind from a region of space creating or (carving out) an (almost) empty cavity–magnetosphere. This the primary effect, not a side effect as you claimed above. Ruslik_Zero 11:40, 17 December 2009 (UTC)

Right, thank you. Can you edit the first sentence appropriately, then?
— V = I * R (talk to Ω) 15:57, 17 December 2009 (UTC)

To say what? That's what the article says now. Serendi^podous 15:58, 17 December 2009 (UTC)

No... it currently says: "The magnetosphere of Jupiter is the cavity created in the solar wind by the planet's magnetic field." I proposed earlier: "The magnetosphere of Jupiter is the region which is created by the planet's magnetic field, which creates a cavity in the solar wind." Feel free to play around with the sentence further, but the difference in meaning between the two is pretty striking, to me. There's a... subject verb difference between the two? I don't really know, I'm an engineering type, not a linguist. Something is decidedly wrong with the current sentence however, as it doesn't communicate what either of you are obviously intending it to.
— V = I * R (talk to Ω) 16:05, 17 December 2009 (UTC)

The only difference between two sentences is that the latter wrongly implies that the magnetosphere and the cavity are two different things. They are not. The magnetosphere is the cavity in the solar wind flow created by the planet's magnetic field. Any definition should make this clear. By the way you have not cited any sources that say otherwise. What you are proposing is actually OR. Ruslik_Zero 16:34, 17 December 2009 (UTC)

Actually, I'd reverse your statement completely, the current wording suggests that the cavity and the magnetosphere are two different things. That's essentially what I've been objecting to all along. You've quoted all of the sources which support this yourself, so I haven't had a need to point out sources myself. I don't want to battle about this or anything... all of the factual points are made correctly in the remainder of the article, and in related articles, anyway. The issue here is simply construction of the first sentence. I'm not sure where or why there is a communication problem here, although there clearly is. We seem to agree on what to say, but we seem to disagree on how to say it (and incidentally the accusations of OR are, frankly, uncivil).
— V = I * R (talk to Ω) 16:54, 17 December 2009 (UTC)

How can a sentence that says that Magnetosphere is cavity mean that the cavity and magnetosphere are two different things? Above you claimed that Magnetosphere is not a cavity. Now you claim that it is. A remarkable U-turn. You seem to have been completely lost in your own arguments. :-)Ruslik_Zero 17:19, 17 December 2009 (UTC)

←humm... we must be getting closer to the problem. Based on some of what you've said above it seems as though our position is the same. We're both stating that we agree with the sources, at least. I think that's why you're interpreting my having taken a "u-turn" here. Let's get off the factual basis of all of this, since we do seem to agree on the facts themselves. As I said above this seems to be a language issue, at this point. The sentence fragment Magnetosphere is cavity is somewhat nonsensical, in English, primarily because... there's no verb? I don't know, like I said above I'm not an English authority, I'm an engineer. There's something here that we're having a fundamental problem communicating to one another.
— V = I * R (talk to Ω) 17:46, 17 December 2009 (UTC)

Are you claiming that Encyclopedia of Astronomy and Astrophysics published by British Institute of Physics uses nonsensical English? Other examples cited above were also written by native speakers. I think it is better for you to simply admit to being wrong, then we can end this discussion. Anyone can be sometimes wrong, nothing special. Ruslik_Zero 20:03, 17 December 2009 (UTC)

Ruslik... wait, you're not a native English speaker? That could explain some things (and, I'm impressed with your grasp of the language. I wish that I could speak any foreign language). The thing is, the sources that you're quoting don't ever exactly say "Magnetosphere is cavity".
— V = I * R (talk to Ω) 20:32, 17 December 2009 (UTC)

So, you claiming that the sentences that says: Jupiter's magnetosphere is the cavity ... does not say that 'magnetosphere is cavity'?. I have never before encountered such bizarre arguments. An what about this, where the first sentence of the introduction says Earth's magnetosphere is a cavity filled with hot but dilute plasma embedded in fast-flowing denser but colder solar wind plasma—exactly what I said above. All cited sources in slightly different words say that magnetosphere is a cavity in the solar wind flow. Ruslik_Zero 06:25, 18 December 2009 (UTC)

Ruslik, I'm trying to bend here to make this acceptable. I make a mistake in the way that I opened this discussion, because as I said above there is actually no factual error here, this is purely a language issue. That being the case, I'm bending over backwards to agree with all of the factual points and stick to the language issue. There's a subject-verb agreement issue with the current sentence is all. IT says what you want it to say if you read it really slowly and already know what it's saying. It would be much clearer and understandable if it were rearranged, which is why I've offered one possible solution above. You're obviously free to rearrange it however you'd like, but it should be done somehow.
— V = I * R (talk to Ω) 13:50, 18 December 2009 (UTC)

Neither me nor Serendipodous see any language issues. The Institute of Physics and scientists working in this field see no issue with language as well. You seem to be along insisting on changing an absolutely correct definition into incorrect one. Ruslik_Zero 16:03, 18 December 2009 (UTC)

Well, if that's the way you're going to be about it then it's probably best to archive this and start an RFC. I'll work on an RFC description and post it later.
— V = I * R (talk to Ω) 16:10, 18 December 2009 (UTC)