Talk:Magnetosphere

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[edit] Comment on page name

This page should be called Earth's Magnetosphere. Previous page correctly (prior to Jan 1, 2006) noted that Earth is not the only planet with a magnetosphere. Content from previous page that defined a magnetosphere in general should link to Earth's Magnetosphere.


What is the current state of the the magnetosphere, isn't it decaying? At what rate? How often do the poles reverse?

[edit] MSPF

There are several references to seeing the MSPF section or page. This doesn't exist on wikipedia, nor is it found through exhaustive use of Google. Due to the level of experience and expertise of the originator DavidStern, I am fairly confident that this copy is valid for Wikipedia use. I've added a request on his Talk Page for the Magnetic Storms and Plasma Flows section to be included.

Xaminmo 15:16, 13 October 2006 (UTC)

[edit] Velikovsky Prediction

I have found many claims on the internet that essentially say:

The Earth's magnetosphere was predicted by controversial author, Immanuel Velikovsky in a letter dated 5 Dec 1956 to Prof. Harry H. Hess in a memorandum on "Tests and Measurements Proposed for Inclusion in the Program of the International Geophysical Year". Velikovsky wrote:
"Measurement of the strength of the terrestrial magnetic field above the upper layers of the ionosphere. It is accepted that the terrestrial magnetic field — about one-quarter of a Gauss at the surface of the earth — decreases with the distance from the ground; yet the possibility should not be discounted that the magnetic field above the ionosphere is stronger than at the earth’s surface."[1]

How does this constitute a "prediction" of Earth's magnetosphere? I don't see the connection. If anyone can provide the connection, please contribute. I have found a discussion of this on Google Groups [2]. I don't think the issuse is settled enough to warrant its inclusion in a encyclopedia article. I have added the link to the Google Groups discussion to the Velikovsky Wiki page.

[edit] Comment to author who cut-and-pasted a web page here in January 2006

Please allow the Wiki community to help. There are some very obvious problems in the current page. For example, the first sentence has two glaring errors:

"The magnetosphere of Earth is the space region whose processes are shaped by the Earth's magnetism ...". The errors are (1) the use of "shape" is inappropriate because a process does not have a shape; "determined" would be more appropriate, but the entire sentence should be rewritten, and (2) magnetospheric processes would not exist without the solar wind.

The above may no longer apply unless it is reverted.

[edit] Coining of the term "magnetosphere"

The current sentence about the coining of the term magnetospehre reads: "The name was suggested by Thomas Gold in 1959, as an upwards extension of the lower part of Earth's atmosphere ...". I don't think this makes sense as it does not make clear if the magnetosphere is part of the atmosphere. I think it would be better to refer to how the region differs physically as in James Van Allen's bio [3] "In 1959 Thomas Gold suggested the term 'magnetosphere' for the region around the earth in which the geomagnetic field has a controlling influence on the motion of charged particles and the term 'magnetospheric physics' was widely adopted. Magnetosphere joined the already established list of 'spheres' -- atmosphere, ionosphere, mesosphere, thermosphere, etc. -- as a geophysical term. "

Any comments?

Sounds great, be bold and go for it, you seem like you're interested in making this artilce better, which is great. --Matthew 15:31, 22 February 2006 (UTC)

[edit] merger proposal

I suggested a merger of Magnetic tail. It seem to be such a related concept and (as of now) such a stubby page that it could just be integrated here. Thoughts? --Chaser T 23:19, 6 June 2006 (UTC)

Great idea. I probably should have just done that in the first place. --S.O.T.A. 23:30, 6 June 2006 (UTC)

[edit] Inverse cube(major error)

This page says: "The dipole field has an intensity of about 30,000-60,000 nanoteslas (nT) at the Earth's surface, and its intensity diminishes like the inverse of the cube of the distance, i.e. at a distance of R Earth radii it only amounts to 1/R³ of the surface field in the same direction."

Why do they say cube? I'm pretty sure it should be the inverse square of distance not cube.

I feel like the author is either correct and are not being clear about what is being measured, or they are wrong.

This is a pretty major error, so I'll probably ask people who can verify 100% on monday and change it then, but if the originator of this claim would like to provide an explanation before then I would appreciate one.

As evidence as to why I believe the article to be incorrect, Look at the wikipedia article on magnetic fields.

It has the following equation for magnetic field strength:

d\mathbf{B} = \frac{\mu_0}{4\pi} \frac{I d\mathbf{l} \times \mathbf{\hat r}}{r^2}

It clearly shows the field strength varying as the inverse square of the radius not the cube. (Look at the term on the bottom) So unless magnetospheric field strength seriously deviates from an ideal magnetic field, there is a major problem here. —Preceding unsigned comment added by 128.97.68.15 (talk) 21:47, 14 December 2007 (UTC)

I think I was just confused, I retract my comment, it should be cube. —Preceding unsigned comment added by 128.97.68.15 (talk) 22:17, 14 December 2007 (UTC)

[edit] CNN said "Mercury is the only planet in the solar system other than Earth to have a magnetosphere"

CNN said "Mercury is the only planet in the solar system other than Earth to have a magnetosphere" in an article from yesterday: http://edition.cnn.com/2008/TECH/space/01/30/mercury.messenger.ap/index.html . Is that true and wikipedia is wrong?, because according to the wikipedia article: "Earth is surrounded by a magnetosphere, as are the magnetized planets Jupiter, Saturn, Uranus and Neptune. Mercury and Jupiter's moon Ganymede are magnetized, but too weakly to trap plasma". Mi intention is not to start a controversy, I just wish someone could clarify this for me because I feel confused. Thanks. --Dhcp 15:50, 31 January 2008 (UTC)

The CNN article is wrong in this case - many planets (as listed in the wikipedia article) have magnetospheres. PhySusie (talk) 16:01, 31 January 2008 (UTC)
Actually that's an AP story from an unknown source. The unknown source might have written from yesterday's MESSENGER press release [4] which compared Mercury's and Earth's field, and which mentioned a few other planets. -- SEWilco (talk) 16:08, 31 January 2008 (UTC)
Both CNN and Wikipedia were wrong. CNN was wrong because several planets besides Mercury and Earth have magnetospheres. Wikipedia was wrong because MESSENGER has shown that Mercury's magnetospheres does trap significant densities of solar wind plasma.[5] I have corrected our lead accordingly. Kaldari (talk) 03:23, 2 February 2008 (UTC)