Talk:South Atlantic Anomaly

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An image to illustrate this would be useful. The last paragraph makes reference to "figures below" which aren't.

Contents 1 Is this backwards? 2 Backward or not depends on your viewpoint. 3 Radiation? 4 Argus connection 5 It may not be backwards... but is the Magnetic Field reversing...? 6 Continental outlines? 7 Operation Argus 8 Insufficient explanation 9 Answering various questions

[edit] Is this backwards?

Is it me or is this article backwards? i.e. the SSA is the van allen belts, caused by the magnetic field. Shouldn't that be the SSA is the magnetic field.... it caues the van allen belts to move etc.

[edit] Backward or not depends on your viewpoint.

I am not a geoscientist and was indeed hoping that something real about the SAA was in Wiki. I worked thru a contractor at NASA for several years as an EE, and issues with the Hubble Space Telescope (HST) involving radiation from the SAA were nontrivial for us.

The limit of my understanding is that there is *something* in the South Atlantic basin that affects Earth's magnetic field enough to warp the Van Allen belts. The effect is that low earth orbit (LEO) satellites like HST pass through a pulled-down edge of the Van Allen belt often--almost once per orbit on average. Low-earth equatorial orbits largely avoid this, while geosynchronous orbits are not only equatorial but higher than the Van Allens (verify?), so they are subjected to general space radiation but not the concentration that Earth's magnetic field has created in the Van Allens.

The excess radiation (gamma-photon-x-ray) due to the SAA fouls up many processes and ages electronics prematurely. Thus, for example, good old micropower CMOS integrated circuits can experience "single event upsets" (SEUs) that can cause systems to go bonkers and require extra design precautions, such as very simple "watchdog" timers that reset the system if they aren't "petted" frequently. New ultrasmall transistor memory locations in VLSI and like devices are also susceptible to SEUs because the capacitors that form the instruction bit storage are small enough to be flipped by the charge that a single gamma ray can induce.

What I was looking for was speculation or better as to what the physical phenomenon that manifests as the SAA actually is. I read somewhere that the name refers to magnetic compass errors, gravimetric irregularities, radar altimeter discrepancies, or some such that coincide spatially with the later-discovered (?) Van Allen issues. I suppose evidence for a hypothetical Mars-sized asteroidal ferrous masscon in the mantle associated with formation of the Moon a few billion years ago would be tough to dig up. Literally.

Compared to this, the Wiki discussion of the K-T boundary debate is rigorous.

Your turn.

[edit] Radiation?

I'm confused. Why would an annomaly in the magnetic sphere cause sattilites to experience more radiation? Could someone clarify that in the article? Thanks! Schwael 17:02, 30 June 2006 (UTC)

[edit] Argus connection

Was there the anomaly before the Argus? And was it also this much radiating?

Can it be, that the anomalous radiation is still the remnant of a nuclear weapon test?

Can it be, that the magnetospheric hole, that makes inner van-Allen belt getting near ground, was caused by that?

[edit] It may not be backwards... but is the Magnetic Field reversing...?

I first heard of the concept of field reversal in a quote Graham Hancock attributed to Albert Einstien in "Fingerprints of the Gods".

Earlier this year, I was channel surfing and came across a documentary on Discovery, or NatGeo. It talked about the fact that every so many hundreds of thousands of years, there is a magnetic field reversal, just as I had read so long ago. It mentioned that the SAA may be symptomatic of this, as it seems to be getting steadily larger and more chaotic.

Some information can be found here: http://www.crystalinks.com/earthsmagneticfield.html

CrusherV 00:12, 17 December 2006 (UTC)

[edit] Continental outlines?

Can someone update the maps to overlay continental outlines? It'd be nice to see exactly where the SAA is.

Also, 0.3 degrees a year means that it travels all the way around the earth in about 1200 years, correct? It might be interesting to search the literature for recurring events, especially in the area of the SAA, which have 1200-year cycles. --Scott McNay 06:34, 1 March 2007 (UTC)

[edit] Operation Argus

What does the comment about Operation Argus have to do with the rest of the article? 65.113.40.130 23:41, 2 May 2007 (UTC)

I agree with 65.113.40.130, I removed the statement from there and added it as "see also" Javit 10:49, 28 May 2007 (UTC)

And I removed the link to it in the "See Also" section. For future reference to those who will read this, the notion that any action of man caused this magnetic anomaly is a physical impossibility. --76.224.71.159 09:38, 2 October 2007 (UTC)

[edit] Insufficient explanation

The SAA is produced by a "dip" in the Earth's magnetic field at that location, caused by the fact that the center of Earth's magnetic field is offset from its geographic center by 450 kilometers (280 miles).

This is insufficient to explain the anomaly, since by itself it implies that there should also be a North Pacific Anomaly. There isn't. Elaboration required. --76.224.92.141 17:31, 26 August 2007 (UTC)

[edit] Answering various questions

On 26 Aug 2007 User:76.224.92.141 noted: This is insufficient to explain the anomaly, since by itself it implies that there should also be a North Pacific Anomaly. There isn't.

This is true. There's no north pacific anomaly. That's because the inner van Allen belt is furthest from Earth's surface over the north Pacific. The belt is symmetric to the Earth's magnetic axis, which is both tilted and offset from the rotational axis.

About the whole Operation Argus thing: Yes, Operation Argus (and later Operation Starfish) did pump a great number of charged particles into the van Allen belts. This caused a temporary increase in the size and intensity of the SAA. The SAA had returned to its pre-test intensity levels by 1967.

Going way back to the first question at the top of the page, it asks: "Is it me or is this article backwards? i.e. the SSA is the van allen belts, caused by the magnetic field. Shouldn't that be the SSA is the magnetic field.... it caues the van allen belts to move etc."

No, the article isn't backward. Earth's magnetic field is not caused by the particles trapped in the van Allen belts. Earth's magnetic field is caused by the dynamo effect resulting from the rotation of Earth's liquid iron core. The magnetic field traps energetic protons and electrons from the solar wind in the van Allen belts. The SAA is not the magnetic field. The SAA is shaped by the magnetic field.

The real experts on the SAA are folks in the Applied Engineering Technology Directorate at the Goddard Spaceflight Center. Look at the literature for articles by E. C. Stassinopoulos and others from AETD for more on the SAA.

BillGawne 18:46, 14 November 2007 (UTC)