Talk:Earth's magnetic field/Archive 2

Archive 1

Archive 2

Magnetic field affects charged particles, NOT ultraviolet radiation!

As far as I understand, Magnetic field deflects only charged particles, but UV is not affected. Am I correct? If so, please alter the article. Dimacq (talk) 23:15, 26 February 2010 (UTC)

The statement has a reference supporting it. If you know of a better reference, supply it and make the change. Thegreatdr (talk) 23:18, 26 February 2010 (UTC)

The reference does not mention magnetic fields and is being used erroneously. I removed that sentence. Crumley (talk) 02:46, 28 February 2010 (UTC)

Generating Electricity

Is it possible to generate electricity at the Earth's magnetic North/South poles?(long duration electric airplanes could navigate within a narrow "recharging zone" to stay aloft), I recall NASA astronauts experimenting with a Italian built "tether" that briefly generated current before the line snapped.Jalanp2 (talk) 19:25, 2 September 2010 (UTC)

You could use the Earth's magnetic field to generate electricity anywhere from the poles to the equator, but it would

not be enough to keep a plane aloft. Crumley (talk) 15:12, 4 September 2010 (UTC)

Radial vs tangential

This entire article never mentions that it pretty much only describes measurements of the tangential magnetic field (the one that drives compasses) and not the radial component, which is about 100-1000 times stronger. Here's some nice illustrations and calculation on the radial component. SamuelRiv (talk) 23:42, 9 February 2011 (UTC)

You need to read the article more carefully - like the part where it says that the magnetic field is straight down at the North Magnetic Pole. Also, the radial field is zero at the geomagnetic equator (where blue meets yellow in the plot your link points to), so it could hardly be 100-1000 times stronger than the tangential field! On the other hand, your confusion may be a sign that the writing in this article needs improving. RockMagnetist (talk) 20:36, 12 October 2011 (UTC)

Statistics

Why can't we have up-to-date statistics on the magnetic field? I propose the following information be added:

• Strength (in Ampres per meter)
• Current (in Ampres)
• Length of circuit (in meters)

I'm not too keen on electrical physics, but I think this is a start.LutherVinci (talk) 12:33, 26 May 2011 (UTC)

The strength is given in B-field units (teslas). While the field is mainly due to currents in the Earth's outer core, we do not know what the currents are, and it is meaningless to talk of a length of circuit because the currents occupy a volume. RockMagnetist (talk) 20:29, 12 October 2011 (UTC)

Organization

This page is really disorganized. I have added a WP:todo box with my suggestions for organizing it. RockMagnetist (talk) 15:36, 4 October 2011 (UTC)

Merge discussion

There is a section in Geomagnetic reversals, titled Future of the geomagnetic field, which has nothing to do with reversals. It would make sense to merge that section with this article. There is already some overlap between it and the section on secular variation. RockMagnetist (talk) 18:24, 17 October 2011 (UTC)

The figure could stay behind to illustrate a new section on excursions. RockMagnetist (talk) 19:35, 17 October 2011 (UTC)

Inclincation

The inclination or dip is the deviation from vertical. WRONG ! The inclination or dip is the deviation from the horizontal. — Preceding unsigned comment added by 124.169.87.193 (talk) 14:25, 8 December 2011 (UTC)

Thanks for pointing that out. Did you know that you can edit pages yourself? RockMagnetist (talk) 15:32, 8 December 2011 (UTC)

InfoBox

The intensity of the earth's magnetic field needs to be mentioned in the first paragraph OR make an infobox on the right hand side.Nscozzaro (talk) 22:51, 22 January 2012 (UTC)

Magnetosphere protection

The intro currently ends:

"The region above the ionosphere, and extending several tens of thousands of kilometers into space, is called the magnetosphere. This region protects the Earth from harmful ultraviolet radiation and cosmic rays."

Since the magnetic field does not affect ultraviolet light (even if UV light is attenuated in the same region which I don't know) we shouldn't imply it by mentioning UV in the intro of this article. Shouldn't we mention that the magnetic field protects from charged particles in the solar wind? RJFJR (talk) 20:36, 24 January 2012 (UTC) I went back and struck the section on solar wind now that I just read our article about cosmic rays and see that charged particles in the solar wind are considered cosmic rays. RJFJR (talk) 20:40, 24 January 2012 (UTC)

The magnetosphere indirectly protects the Earth from ultraviolet rays. See Earth's magnetic field#Importance. RockMagnetist (talk) 21:33, 24 January 2012 (UTC)

That is really saying the magnetic field is protecting the atmosphere from erosion. May be we should say that. RJFJR (talk) 21:45, 24 January 2012 (UTC)

Feel free to modify it. RockMagnetist (talk) 21:58, 24 January 2012 (UTC)

I changed it to "This region protects the Earth from cosmic rays and the atmosphere from being stripped away including the ozone layer that protects the earth from harmful ultraviolet radiation." RJFJR (talk) 17:03, 25 January 2012 (UTC)

Thanks. I reworded it a little because it might seem odd that we are worrying about the ozone layer if the whole atmosphere is being stripped away. It would take billions of years to strip away the entire atmosphere but probably much less to destroy the ozone layer. RockMagnetist (talk) 17:48, 25 January 2012 (UTC)

(Future) Please use consistent units when talking about the same thing, especially within a paragraph!

The last paragraph under "Future" tells how the magnetic north pole has been drifing at different rates over the last century or so. Different sources may give different units, but whoever writes or cleans up the paragraph should convert them all to the same unit. The pole is drifting "with a presently accelerating rate—10 km per year at the beginning of the 20th century, up to 40 km per year in 2003,[29] and since then has only accelerated.[30] In the last decade magnetic north was shifting roughly one degree every five years." The earlier figures should be converted to degrees (or decimal fractions) per year, or the last one converted to km per year. Otherwise there's no easy way to tell how the current rate of change is different from the earlier figures. Benbradley (talk) 19:03, 22 March 2012 (UTC)

I checked the source for the latter figure, and it is based on a newspaper account that is too vague to be useful. It is really referring to magnetic declinations everywhere, not the movement of magnetic North, and it implies that the latter depend on the former, which is not true. It seemed better just to remove the offending statement. RockMagnetist (talk) 21:42, 22 March 2012 (UTC)

Core Conductivity

Any ideas on where the recent Nature letter to the editor which uses first-principles calculations to come up with substantially higher electrical conductivity than usually assumed should be referenced? Dan Watts (talk) 03:54, 22 May 2012 (UTC)

Inner or outer core? The reference could go in Earth's magnetic field#Earth's core and the geodynamo, but only in the context of quantitative numerical models of the dynamo. That would take some writing. You could put the reference here for future contributors; and you could also look into adding it to Inner core or Outer core, whichever is appropriate. RockMagnetist (talk) 04:11, 22 May 2012 (UTC)

Inner core.

Dave Gubbins strikes again! Thanks for the reference. RockMagnetist (talk) 14:57, 22 May 2012 (UTC)

References

Tilt of geomagnetic dipole

I changed the tilt of the dipole back to 10°. I have seen that figure 11.3° somewhere, but it is not up to date. As of 2010, it was at 9.98° (see "Where are the magnetic poles?" in the citation I added). RockMagnetist (talk) 15:33, 15 July 2012 (UTC)

Earth's core and the geodynamo

The concepts about the motion of charges, as an underlying requirement for the article's calculations to be valid, would be obvious to any person versed in the physics of electromagnetism. The source of those moving charges is not addressed elsewhere in the article. I stated certain mechanisms for current generation that have been mentioned in the literature, and provided references. To say that my contribution amounts to vandalism because Mr. RockMagnetist did not like my references is petty, lazy, and is like throwing the baby with the bath water. If Mr. RockMagnetist dares to be constructive instead of destructive by deleting everything I wrote, he should enrich the article by providing more references (or even, references negating what I say, if he can find any). If even basic notions of electromagnetism need to be referenced everywhere in the article then, most of the article would need to be deleted according to Mr. RockMagnetist. — Preceding unsigned comment added by 98.217.147.183 (talk) 00:48, 10 December 2012 (UTC)

Since the origin of the currents is explained at the beginning of this section, the need for further explanation is not "obvious to any person versed in the physics of electromagnetism." My edit summary referring to citations is a polite way of saying that you are wrong. If you can find references that actually support your statements, then you can consider adding the material back. RockMagnetist (talk) 01:09, 10 December 2012 (UTC)

Sorry for labelling your edit "vandalism". I use Twinkle for many of my messages and sometimes I'm careless about the choice of message. I do believe your edits are in good faith. RockMagnetist (talk) 05:22, 10 December 2012 (UTC)

I see you have added a revised paragraph with new citations. The references do not support the idea of remanent magnetization in the mantle providing the seed field for a dynamo; in fact, in page 3 of his thesis, Livermore states that "The idea of permanent magnetism (the only form known at that time) suffered a fatal blow when it was realised that almost all of the Earth’s interior was too hot (above its Curie temperature) to retain its magnetisation". However, I now see what you're driving at. It is true that a dynamo needs a "seed" field to get started; but once the dynamo has started it doesn't need any further input. I have some good references on that, and I'll add some material. RockMagnetist (talk) 05:38, 10 December 2012 (UTC)

It appears we have one too many images in the article

All the images were moved over to the right to diagnose whether or not we have too many images. It appears we have one too many. Remember that there should not be images on both sides of any particular section of the article, per wikipedia standards. If you want to the link for this standard, I can provide it easily enough. Thegreatdr (talk) 15:04, 2 April 2013 (UTC)

I think the images are all very useful and relevant, but the clutter has bothered me. I don't know why I didn't think of this before, but moving the three component maps into a gallery section helps a lot. The image in Earth's magnetic field#Dipolar approximation is still too large, but when I reduce its size the notations become illegible. I think there is more to say on the dipole approximation, so when the text is added this problem may solve itself. RockMagnetist (talk) 16:24, 2 April 2013 (UTC)

This is the first time I've truly liked the use of a gallery section in a wikipedia article. It only takes up one row, and it is within the section it needs to be located within. I'm guessing this is the way it was intended. Well done. =) Thegreatdr (talk) 17:15, 2 April 2013 (UTC)

Thank you. I know what you mean about not liking galleries. That's probably why it took me so long to think of it. RockMagnetist (talk) 17:20, 2 April 2013 (UTC)

Dipolar approximation - direction of magnetic flux

Just a bit confused here. Conventionally lines of magnetic flux are shown going from the N magnetic pole and entering the S magnetic pole, see e.g. Bar magnet#Modelling magnets. I understand that the N pole of my compass must point to a S pole, but I am not sure the article is correct in saying that the magnetic N pole is actually a S pole. I think the magnetic N pole is a N pole, and it is therefore the S pole of my compass that points to it (i.e. the S pole of my compass is labelled N for map reading purposes rather than to identify magnetic polarity). I'm also confused by the direction of the field lines in the figure ("The variation between magnetic north ...") - they have a red arrow in one direction and a black arrow in the other. Aarghdvaark (talk) 13:48, 21 May 2013 (UTC)

Rather than arguing over something that is a matter of definition, I'll point you to a Scientific American article. The little arrows represent compass needles. The north pole of a compass needle is often colored red; it is the direction that corresponds to the direction of the arrows in File:VFPt cylindrical magnet thumb.svg. RockMagnetist (talk) 14:54, 21 May 2013 (UTC)

Thank you for this. The quote from the Scientific American article: "From a physics standpoint, then, the north needle of a compass (or any magnet) points to what is physically—but not in name [because it's called the north magnetic pole]—the south magnetic pole of the earth, in other words, in the direction of the Arctic." rather startled me. Just using single black arrows then, arrows indicating magnetic flux should point to the Earth's north magnetic pole (as the red arrows do) because its magnetic polarity is that of a south pole? Very peculiar. Aarghdvaark (talk) 15:19, 21 May 2013 (UTC)

GA Review

This review is transcluded from Talk:Earth's magnetic field/GA1. The edit link for this section can be used to add comments to the review.

Reviewer: Jamesx12345 (talk · contribs) 17:38, 30 September 2013 (UTC)

This looks like a fun one to review. James^x12345 17:38, 30 September 2013 (UTC)

• "also known as the geomagnetic field" - "also known as the geomagnetic field"Y
• "energetic particles" - "charged particles"Y
• "simple compass" - "ordinary compass"Y
• link ozone layerY
• "The magnetic field of the Earth largely deflects most of the charged particles emanating from the Sun, thus protecting it from this solar wind." - "The magnetic field of the Earth largely deflects most of the solar wind emanating from the Sun, protecting it from the charged particles that would strip away the ozone layer which protects the Earth from harmful ultraviolet rays." I think this makes more sense, but isn't perfect.Y
• I would personally dissolve the Importance heading into the intro. It only seems to provide background information - except for navigation, which could be a whole new heading under which Biomagnetism is a sub-heading.
• "The intensity of the field is greatest near the poles and weaker near the Equator" - needs a cite, as does "The field ranges between approximately 25,000 and 65,000 nT (0.25–0.65 G)."Y
• I'll set up a notes heading - just to prove I can :-) - for the non-ref. Not done
• What's a fridge magnet?Y
• Map of intensity and maxima/minima need refsY
• Inclination and Declination are also unsourced.Y
• The size of the images mean they are just "piling" down the right hand side - moving one or two to the left should fix that. Maybe
• Angle of tilt is 10 here - 11 in intro. One is out of date (presumably the smaller one?)Y
• Magnetic poles starts to get confusing. I'll have a think about how to make it less so.Y

@Jamesx12345:, sorry for the slow response. I am the main contributor to this article, but someone else nominated it and I somehow failed to notice the review! I'll start with the easy changes. I have done the minor wording changes (first five points). Ozone layer had a link, but I moved the link to the first appearance of the term. I have come up with an alternative wording for the longer passage, which I hope you'll like. RockMagnetist (talk) 21:11, 18 October 2013 (UTC)

The maps of intensity, inclination and declination can be covered by a single reference, which I have provided. My comment about the intensity of the field being greatest near the poles, etc., is a bit of an overstatement. I have made a more cautious statement and referred to the map of inclination for support. RockMagnetist (talk) 21:42, 18 October 2013 (UTC)

The current tilt is 10 degrees, so I have changed the lead. I wish it were true that moving the images to the left improved appearances. I have tried all sorts of arrangements, and having everything on the right seems the least bad. Probably the best solution (aesthetically) would be to add more text. Feel free to experiment, though. RockMagnetist (talk) 21:50, 18 October 2013 (UTC)

I considered setting up a Notes section, but realized that it would have contained a single note. Instead, I have embedded the note into the text. RockMagnetist (talk) 22:00, 18 October 2013 (UTC)

I think that Magnetic poles may be confusing because I didn't emphasize the local vs global nature of the definitions. I hope my rewording makes sense. RockMagnetist (talk) 22:16, 18 October 2013 (UTC)

Hi. I thought this nomination had been abandoned, and was planning to close it in due course. I'll get on with reviewing the rest of the article over the weekend. Sorry about the slightly patronising tone - not intended. James^x12345 12:54, 19 October 2013 (UTC)

I'm glad I caught it in time! I didn't notice a patronizing tone. RockMagnetist (talk) 22:12, 20 October 2013 (UTC)

Part 2

• "as though on an electromagnetic energy transmission line" - not sure what that is the best analogy.Y
• "solar wind is observable on the Earth" - you don't see the solar wind directly, just its effects.Y
• "inflate and thereby distort" - thereby could be removedY
• This latter half of this paragraph is doesn't appear to be sourced.Y
• The solar wind is responsible for... gets a bit unclear here again. It isn't clear what variations are being referred to.Y
• "A movie on the right" - an animationY
• Geomagnetic reversal can be linked Not done
• "in basalts, sediment cores taken from the ocean floors, and seafloor magnetic anomalies." - needs a ref.Y
• "However, a study published" - this sounds out of place (as if it was added later.)Y
• "Temporary dipole tilt variations that take the dipole axis across the equator and then back to the original polarity are known as excursions." - this needs a sourceY
• Future needs a few more refs as well.
• Are there more up-to-date sources for the drift of the magnetic north pole? Not done
• The first paragraph of Earth's core and the geodynamo needs a ref or two.Y
• "motion driven by buoyancy" could probably be removed. Maybe
• "both mechanisms somehow discredited" - this needs a ref, and some clarification.Y
• "Philip William Livermore" - since there is no page for him, the name can probably be removed, and the ref filled out to include his name.Y
• "Typical daily variations of field strength..." - "1 part in x" might be a clearer way of explaining the magnitude of deviation.Y
• Crustal magnetic anomalies needs a few refs again.
• (See magnetic storm.) can probably be taken out.Y
• Detection has lots of discrete unreferenced sentences, which doesn't look great. Running them together would improve the flow.
• Statistical models needs to be sourced. I don't know if it could be expanded at the same time as well. Not done
• Perhaps Global models and Statistical models could be merged? Not sure

Magnetic field reversals

• I didn't link Geomagnetic reversal, per WP:OVERLINK, because it is already listed as the main article for that section.
• "However, a study published" overstates the importance of that study and fails to place it in context. I have corrected it. RockMagnetist (talk) 21:38, 20 October 2013 (UTC)
• The irony of the statement about worldwide evidence for reversals - it's one of the crucial arguments for the reality of reversals, yet it's remarkably hard to find a statement of it on a single page! I found one, though. RockMagnetist (talk) 21:50, 20 October 2013 (UTC)

Earth's core and the geodynamo

• A couple of comments relate to a rather confused paragraph that was added in 2012 (with statements not supported by the citations). I have removed it. RockMagnetist (talk) 22:04, 20 October 2013 (UTC)
• My feeling about "motion driven by buoyancy" is that it allows the reader to keep reading without consulting the link to convection. However, if you disagree, I'll remove it. RockMagnetist (talk) 22:10, 20 October 2013 (UTC)
• I see a lot of complaints about the accessibility of this section in reader feedback, so I added a less technical first paragraph. RockMagnetist (talk) 21:56, 21 October 2013 (UTC)

I was going to suggest that as well. I counted at least four that were looking for its role in protection from cosmic rays, which seems to be a class research favourite.

Statistical models

• I know it's really hard to tell from the typography, but Global models is already a subsection of Statistical models. My intent is to have a general description of how the global field can be modeled, and then describe the widely used models. Any suggestions on making that more clear would be welcome. RockMagnetist (talk) 22:19, 20 October 2013 (UTC)
• This section is sourced. If an entire paragraph comes from the same source, I put the source at the end of the paragraph. RockMagnetist (talk) 23:36, 21 October 2013 (UTC)

Magnetic poles

• Yes, there are more recent figures - on pages like zengardner.com, godlikeproductions.com, and metabunk.org (the Earth's magnetic field seems to to inspire a lot of nuttiness). I couldn't find anything reliable, though. RockMagnetist (talk) 22:06, 21 October 2013 (UTC)

I found that, oddly enough, with James Clerk Maxwell. The oddest things attract people...

I'm happy to pass this now. It definitely meets the criteria in its current form, but a more accessible section would be a bonus. Thanks for putting up with my reviewing. James^x12345 17:10, 22 October 2013 (UTC)

Thanks for all your work in reviewing it! RockMagnetist (talk) 17:18, 22 October 2013 (UTC)

Thank you both for taking the time.Fgnievinski (talk) 02:30, 23 October 2013 (UTC)

✓ Pass

Although the article is passed, many of the comments remain true and deserve a response. There were several comments on Magnetosphere; I decided to rewrite it completely to give it more coherence and better coverage of the material. RockMagnetist (talk) 23:45, 24 October 2013 (UTC)

Latitude and poles and equator: actual vs. dipole, or local vs. global

I think there's a need for unifying related concepts that are currently scattered and even duplicated. There are actual north/south poles and equator, defined based on the local absence of the horizontal and vertical components of the magnetic field, respectively. Then there are counterparts in a global best-fitting dipole. The explanation that dipolar poles are antipodal and the dipolar equator is planar, whereas the actual ones are not, provides a vivid picture of the distinction. The existing terminology -- e.g., Earth's magnetic poles vs. geomagnetic poles; dip poles vs. dipole poles -- couldn't be more unfortunate, so why not stick to actual and dipole latitude, poles, equator? I'd like to seek your input about an article or section titled Latitude, equator, and poles of the Earth's magnetic field. Relevant sections and articles: Earth's magnetic field#Dipolar approximation, Earth's magnetic field#Magnetic poles, Geomagnetic latitude, Dipole model of the Earth's magnetic field, Geomagnetic pole, South Magnetic Pole, North Magnetic Pole, and redirects South Geomagnetic Pole, North Geomagnetic Pole. Thx. Fgnievinski (talk) 01:05, 22 October 2013 (UTC)

I have struggled with the question of how to distribute the information on magnetic poles, and I don't see any easy answers. For example, see my views of the pros and cons of merging South Magnetic Pole with North Magnetic Pole. I agree that the existing terminology isn't so great, but I don't think we should make up our own. Anyway, I'm not sure that everyone would agree the North Magnetic Pole is the "real" one. I'd be tempted to merge Dipole model of the Earth's magnetic field into this article. I'd be reluctant to combine Earth's magnetic field#Dipolar approximation with Earth's magnetic field#Magnetic poles because I think the former should include the equations for a dipolar field. However, the geomagnetic pole itself could be discussed in Earth's magnetic field#Magnetic poles. RockMagnetist (talk) 16:44, 22 October 2013 (UTC)

Campbell (1996) argues strongly against unqualified "magnetic pole", although he has no problem with "geomagnetic poles"; my interpretation is that he recommends "dipole poles" and "dip poles", see:

Positions, symmetric in the two hemispheres, where the dipole would intersect the Earth's surface, are called the "Geocentric Dipole Poles," or simply the "Geomagnetic Poles."

If the full 10 degree-and-order terms of the IGRF are used to determine where, in the polar regions, the field seems to be most vertical, then this place is called the "IGRF Model Magnetic Dip Pole" position, or simply the "Model Dip Pole."

'Instead of calculating it from the IGRF model, a ground survey of the relevant polar regions can be carried out to find, by actual measurement, where the field is most fully vertical (90°) in dip. ... The determined position is the true "Magnetic Dip Pole" and would be a unique location for a chart because it is where a person traveling in the region could observe a vertical field."

Notice he calls the measured dip pole the true magnetic pole. A similar statement is also found in this authoritative guide (p.22):

... the actual magnetic poles, where the field is vertical, do not coincide with the geomagnetic poles of the harmonic representation, and move from year to year. The actual magnetic equator is not a simple circle, as the geomagnetic one in Fig. 2.5. The actual north magnetic pole, the dip-pole, [is] where the magnetic field is vertical in the northern hemisphere... The dip-equator or magnetic equator is situated where the lines of force are horizontal.

So I think we should present all the terminology -- dipole/geomagnetic vs. magnetic/dip (modeled & measured) -- in one place, and for all of poles, equator, and latitude. Fgnievinski (talk) 19:18, 22 October 2013 (UTC)

Sounds like a good idea. How about expanding Earth's magnetic field#Magnetic poles? I'd be o.k. with renaming it Magnetic poles, equator, and latitude. I'm also inclined to propose Geomagnetic latitude for deletion. RockMagnetist (talk) 21:08, 22 October 2013 (UTC)

Also found this: Meridian (geography)#Magnetic; so now with magnetic longitude onboard, maybe we're talking about #Spherical coordinates... (Will have to set this aside for a while now.) Fgnievinski (talk) 02:51, 23 October 2013 (UTC)

Reader feedback: help to understand the topic...

117.203.22.196 posted this comment on 11 July 2012 (view all feedback).

help to understand the topic "how the electromagnetic field of the earth is generated?" for begineers to make it easy to understand..!!!

Any thoughts?

Kortoso (talk) 20:44, 31 October 2013 (UTC)

Try this page instead:

https://simple.wikipedia.org/wiki/Earth%27s_magnetic_field

If you replace the "en" in most Wikipedia pages with "simple", it might be easier to understand.

Kortoso (talk)

The explanation in Simple English Wikipedia is garbled: "When the convective motions occur with the electrical currents around the Earth, the magnetic field is created." What does that mean? "The Earth’s rotation is what keeps the magnetic field up" is wrong (and contradicts the previous sentences). I saw some of that feedback and added an introductory paragraph to the section Earth's core and the geodynamo, and Chetvorno added an even simpler summary at the top of Physical origin. I do want to make this article as accessible as possible, but if you try to simplify it too much it stops making sense. RockMagnetist (talk) 21:05, 31 October 2013 (UTC)

Puffery of sorts? Is the magnetic field really important?

If I were a geophysicist, I might be climbing in to do some editing, but I am not, so lets discuss matters first. If anyone can clarify some points in the Importance section, it would save me a lot of trouble and maybe save a lot of reader confusion. Having swallowed the party line for many years, I am increasingly sceptical about the nontrivial importance of the magnetic field, particularly concerning protection of the planet from radiation from space, whether solar wind, cosmic ray particles, photons, you name it.

Firstly. Irrespective of how important the magnetic field really might be, some of the refs are at once speculative and only tenuously relevant to material threats. I'm not saying they are wrong (though not persuasive) but what they say certainly isn't what they are supposed to be supporting, such as "The charged particles in the solar wind would strip away the ozone layer..." This is without even discussing the real nature of the protection of the ozone layer.

Again, "Calculations [of]... scavenging of ions by the solar wind, indicate that the dissipation of the magnetic field of Mars caused a near-total loss of its atmosphere.." simply is not supported by the reference, which is a popularised article that might for all I know reflect the source fairly, but it derives the conclusion tenuously and a good deal more speculatively than the text of the WP article: "...entertains a third possibility; a daily ripping process intermediate between the other two mechanisms..." It also does not explain how much of a similar effect would apply to Venus (very weak field) or to Earth if it were to lose its field. In short it is not a sound citation at all. As it stands that citation is not acceptably encyclopaedic at all.

The claim that "Variations in the magnetic field strength have been correlated to rainfall variation..." also puts it more strongly than the source does, though that source looks sounder than the other two.

So: could someone either supply more substantial citations of sounder sources and more relevant claims, or delete or modify the interpretations? Or tell me why not to replace such claims with something along the lines of: "Speculations have been published that the Earth's magnetic field has a substantial protective effect against... but substantial support for such conclusions is not as yet forthcoming." (That is thumbsuck wording; open to negotiation as always.) JonRichfield (talk) 18:08, 13 December 2013 (UTC)

I second. I sincerely think the importance section is flawed and some claims are highly speculative. For example, I've learned the low mass / gravity of Mars is the main reason for its atmospheric loss. Consider that Venus has no intrinsical magnetic field either. Venus' weak magnetic field is induced by solar wind interaction with the atmosphere (e.g. check Venus Express mission papers, but I think this was known well before), an induced protection mechanism which would most probably have worked on Mars as well if its mass would have been similar. I think the sources given here should be taken with care and double-checked. --213.144.3.86 (talk) 09:06, 27 July 2015 (UTC)

Thought about placing a POV sign, however the (in my opinion) flawed statements appear to be backed up by papers, so if I should have enough time at some point, I might look into more literature about the topic. However, help here would be appreciated. --213.144.3.86 (talk) 09:16, 27 July 2015 (UTC)

Thank you both for raising some interesting issues. @JonRichfield: sorry for taking so long to reply - your comment must have arrived when I was busy with real life. I'll look into it, and if you find any good sources, let me know. RockMagnetist(talk) 17:03, 27 July 2015 (UTC)

No problem @RockMagnetist. I snatched a moment form RL myself, and found what looks like a nice pointer at http://www.space.com/11187-earth-magnetic-field-solar-wind.html I liked it because it seemed to point along some lines that I had worked out for myself some years ago, plus more sophisticated material. Then there is this one, that blindsided me completely: http://www.livescience.com/24423-earth-magnetic-field-sieve.html JonRichfield (talk) 13:15, 29 July 2015 (UTC)

Fascinating! I think this issue should become a subsection of Earth's magnetic field#Magnetosphere, which also discusses it. But the article Magnetosphere doesn't, so to keep the articles synchronized we should probably add a section there first and then summarize it here. While we're at it, the rest of Earth's magnetic field#Importance should be disbanded and its contents moved elsewhere. Having a section header like that makes a neutral presentation difficult. RockMagnetist(talk) 15:44, 29 July 2015 (UTC)

Earth's core and the geodynamo

There is a discussion of this article's content on this user page. RockMagnetist(talk) 17:21, 29 September 2015 (UTC)

I am going to revert this edit. It is full of errors and misleading statements. Among the errors:

• A "seed" field is only necessary to start the dynamo, not to sustain it.
• The relevant Curie temperature is that of iron oxides such as magnetite (853 K). Pure iron is a negligible part of the upper mantle.
• Much of the magnetization in deep rock is induced, not remanent; and any remanence will be the result of the Earth's magnetic field, not its cause.

Moreover, I have looked at the PhD thesis and it is not the source of any of this material. RockMagnetist(talk) 17:39, 29 September 2015 (UTC)

I reviewed the edits that you discarded and, there was not a single error nor any misleading statements. The so called "errors" that you list above were not in the text you reverted! While the text referred to "seed “stator” magnetic fields", nowhere in the text it is implied that such fields are necessary to sustain the dynamo, as you report. On the contrary, the "seed" implies the starting of the currents, and not necessarily their maintenance. No error there.

Iron was mentioned only, and explicitly so, as an example of the magnitude of a Curie temperature. The text actually discussed "magnetic materials in the upper mantle". No claim was made of iron being more relevant that the oxides. Grant you that oxides may be more abundant however, there are reducing reactions within the mantle and, even if pure iron were a "negligible" part of the upper mantle, as you say, you are corroborating that iron is present. No error there.

Ferromagnetic rocks have hysteresis. Once they have been exposed to a magnetic field, for example resulting from sun activity, there will be a remnant magnetic field left in them. It is that remnant magnetic field the one it was referred to in the text you discarded. There is no proof or indication that the current Earth magnetic field and dynamo were always present in the history of our planet. When suitable conditions arouse, the remnant magnetic fields provided one of the likely sources for the seed fields. Even if there are other possible mechanisms, no errors nor misleading statements were there either.

By the way, early sources of magnetic fields could have existed prior to the geodynamo (even you mention them in your new edits). So, you are mistaken when you say "any remanence will be the result of the Earth's magnetic field, not its cause". That is also misleading.

Lastly, the PhD thesis was the actual source where I extracted that the seed “stator” magnetic fields would induce the required growing currents in the convectively driven fluid behaving as a dynamo.

It looks like you did not read well or, misunderstood the contents of what you reverted. It would have been more constructive to have edited the text to improve its style/syntax and, to ad your contribution. However, you threw the baby out with the bathwater, something that I've noticed you, and others, do disgustingly often in Wikipedia. 98.217.158.136 (talk) 09:17, 3 October 2015 (UTC)

When more than one editor finds a paragraph confusing, the odds increase is that the problem is with the content, not the readers. I agree that a seed field is needed, and I appreciate your bringing the issue up. I state the role of a seed field clearly in my version. However, I could find no sources to support the idea that magnetic remanence in the mantle could have been the source of the seed field. In any case, even if there was remanence in the rocks before the geodynamo started up, there would have to be a field to give them a remanence, wouldn't there? They couldn't just magnetize themselves. So magnetic remanence is not the solution. RockMagnetist(talk) 17:33, 3 October 2015 (UTC)

Title: Move to Geomagnetic field (or similar)

Conventionally, "the magnetosphere of the Earth" refers to the external extent of the Earth's magnetic field in space where it is shaped and affected by the solar wind. But the title of this article uses the term "magnetosphere" in an unconventional way to refer to all of the Earth's magnetic field, including its internal dynamo, secular variation, polarity reversals, etc. Though this might seem "logical", as all of the geomagnetic field is contained within the external field, scientists don't normally us the word "magnetosphere" in such an all-inclusive way. I suggest changing the title of this article "Geomagnetic field". I tried to do this, but since there is a redirect in place from that term to "Magnetosphere of Earth", I was prevented from making such a move.

Do we agree that "Geomagnetic field" is a more appropriate title? If so, can someone with more understanding of how to do this, then, please move the article to that title? Thanks, Isambard Kingdom (talk) 13:02, 27 June 2016 (UTC)

I also think that "Magnetosphere of Earth" is not an appropriate title, for exactly the reasons you describe. I would support changing the title to "Geomagnetic field" or back to the original "Earth's magnetic field". Cavit2 (talk) 17:25, 27 June 2016 (UTC)

The change of name was requested as an "uncontroversial" move for supposed consistency with articles such as Magnetosphere of Jupiter. But it is controversial, and rightly so, because it is incorrect. I have reverted to the previous title. Now we can discuss a possible move to "Geomagnetic field". RockMagnetist(talk) 18:48, 27 June 2016 (UTC)

Thanks, RM. I'm fine with "Earth's magnetic field". Isambard Kingdom (talk) 22:01, 27 June 2016 (UTC)

Magnetosphere of Earth has now been nominated for RfD. An RM will be discussed in the section below. GeoffreyT2000 (talk) 19:51, 27 June 2016 (UTC)

Requested move 27 June 2016

The following is a closed discussion of a requested move. Please do not modify it. Subsequent comments should be made in a new section on the talk page. Editors desiring to contest the closing decision should consider a move review. No further edits should be made to this section.

The result of the move request was: Not moved. (non-admin closure) — Andy W. (talk · ctb) 00:59, 5 July 2016 (UTC)

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Earth's magnetic field → Geomagnetic field – See the section above. The name "Geomagnetic field" is a shorter name and also a more common name. GeoffreyT2000 (talk) 19:54, 27 June 2016 (UTC)

• Oppose per WP:COMMONNAME. Both names are valid, but Earth's magnetic field seems to be used more often in reliable sources:

• Google scholar: 227,000 results for geomagnetic field and 308,000 results for Earth's magnetic field.
• Google books: 148,000 vs 301,000

RockMagnetist(talk) 20:16, 27 June 2016 (UTC)

• Oppose tentatively, adding the point that for consistency with other planets' articles, should they be renamed as they too encompass more than simply their magnetosphere, and seeing as there are no common names like "Jovimagnetic" (though there is "Heliomagnetic", but that's the only one I know), such that their likely option would be to move to an article name like "Jupiter's magnetic field" or similar, and as this sentence is getting way too long, it seems that "Earth's magnetic field" is the right choice for long-term consistency. SamuelRiv (talk) 20:28, 27 June 2016 (UTC)

Rather than aiming for a consistent name, we should look at the contents. Magnetosphere of Mercury has very little on its magnetosphere, so Mercury's magnetic field would be more appropriate; but Magnetosphere of Jupiter only has a couple of paragraphs on its internal magnetic field. I think that their names are best discussed on the individual pages. RockMagnetist(talk) 21:25, 27 June 2016 (UTC)

I see that Magnetosphere of Mercury was renamed from Mercury's magnetic field after an "uncontroversial technical move" request by that same @JorisvS. RockMagnetist(talk) 21:29, 27 June 2016 (UTC)

RM is correct, and we need to use terms as they are conventionally used. In this case, this article is about the magnetic field of the Earth, a subject that encompasses (but is not equivalent to) the subject of the magnetosphere of the Earth. Isambard Kingdom (talk) 22:05, 27 June 2016 (UTC)

• Oppose per Isambard Kingdom's explanation. — Gorthian (talk) 20:11, 28 June 2016 (UTC)
• Oppose I agree with RockMagnetist's argument that Earth's magnetic field is the more common name. Making Geomagnetic field and Magnetosphere of Earth redirects will prevent any confusion. --Chetvorno^TALK 01:41, 29 June 2016 (UTC)

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The above discussion is preserved as an archive of a requested move. Please do not modify it. Subsequent comments should be made in a new section on this talk page or in a move review. No further edits should be made to this section.