Switching Poles...

[Turtle]

Good thing about knowledge is that it's always amendable.:phones: All this prodding on Eclog's part & all this searching on my part has swayed me round to at least some of the specifics I argued.

To whit, the atmosphere is the 'big dog' protecting Earth from solar UV and X-ray radiation. My error in this appears to derive from a combination of not enough knowledge of high energy physics + widely spread popular science media references to Earth's magnetic field as 'protecting' us.

I have to ask Eclog when/where/how/who this idea started & how/why has it persisted? (Obviously I played my part in propogating it:hyper: )

What info/observations do you have on the solar storm-power grid scenario?

Duty calls; I have to run. Good stuff Eclog.:evil:

[Eclogite]

I think this research is apposite:

 

M C Thorne Background radiation: natural and man-made 2003 J. Radiol. Prot. 23 29-42

 

Abstract. A brief overview and comparison is given of dose rates arising from natural background radiation and the fallout from atmospheric testing of nuclear weapons. Although there are considerable spatial variations in exposure to natural background radiation, it is useful to give estimates of worldwide average overall exposures from the various components of that background. Cosmic-ray secondaries of low linear energy transfer (LET), mainly muons and photons, deliver about 280 µSv a-1. Cosmic-ray neutrons deliver about another 100 µSv a-1. These low- and high-LET exposures are relatively uniform to the whole body. The effective dose rate from cosmogenic radionuclides is dominated by the contribution of 12 µSv a-1 from 14 C. This is due to relatively uniform irradiation of all organs and tissues from low-energy β particles. Primordial radionuclides and their progeny (principally the 238 U and 232 Th series, and 40 K) contribute about 480 µSv a-1 of effective dose by external irradiation. This is relatively uniform photon irradiation of the whole body. Internally incorporated 40 K contributes a further 165 µSv a-1 of effective dose in adults, mainly from β particles, but with a significant γ component. Equivalent doses from 40 K are somewhat higher in muscle than other soft tissues, but the distinction is less than a factor of three. Uranium and thorium series radionuclides give rise to an average effective dose rate of around 120 µSv a-1. This includes a major α particle component, and exposures of radiosensitive tissues in lung, liver, kidney and the skeleton are recognised as important contributors to effective dose. Overall, these various sources give a worldwide average effective dose rate of about 1160 µSv a-1. Exposure to 222 Rn, 220 Rn and their short-lived progeny has to be considered separately. This is very variable both within and between countries. For 222 Rn and its progeny, a worldwide average effective dose rate is about 1105 µSv a-1. For 220 Rn and its progeny, the corresponding value is 91 µSv a-1. In both cases, the effective dose is mainly due to α particle irradiation of the bronchial tissues of the lungs. Overall, the worldwide average effective dose rate from natural background is about 2400 µSv a-1 or 2.4 mSv a-1. For comparison, worldwide average effective dose rates from weapons fallout peaked at 113 µSv a-1 (about 5% of natural background) in 1963 and have since fallen to about 5.5 µSv a-1 (about 0.2% of natural background). These values perhaps serve to emphasise that even gross insults to the natural environment from anthropogenic releases of radioactive materials are likely to be of limited significance when set in the context of the ambient radioactive environment within which all organisms, including humans, have developed.

 

Link: http://www.iop.org/EJ/abstract/0952-4746/23/1/302

[Turtle]

I think this research is apposite:

Link: http://www.iop.org/EJ/abstract/0952-4746/23/1/302

 

It struck me the same way. I recant my heresay...er, heresy & genuflect in your specific direction. Shall we dine?:) :eek2: [i'm serving fresh fish with the bier tonight, but the only foodicon I found was pizza:shrug: ]

[CraigD]

All this prodding on Eclog's part & all this searching on my part has swayed me round to at least some of the specifics I argued.

To whit, the atmosphere is the 'big dog' protecting Earth from solar UV and X-ray radiation. My error in this appears to derive from a combination of not enough knowledge of high energy physics + widely spread popular science media references to Earth's magnetic field as 'protecting' us.

It’s wonderful to see hypography accomplish its purpose of hosting ideas and spreading knowledge. Applause for Eclog, Turtle, and hypography in general!

 

Let’s be cautious, however, not to conclude that a major decrease in the Earth’s magnetic field would be a minor event. The solar wind is a huge source of high-velocity atomic nuclei, most of which are currently, due to the Earth’s magnetic field, not striking its atmosphere of surface. It’s a medical known that photons produced by those that do strike the atmosphere can cause damage cells and cause disease, so, even absent a precise prediction of the world-wide health impact of a pole reversal, it’s not inaccurate to say that both the Earth’s magnetic field and its atmosphere are important shields between the environment of interplanetary space and biological life.

I have to ask Eclog when/where/how/who this idea started & how/why has it persisted?

If I may speculate, I’d say the idea didn’t start, but became accepted fact in 1958, when the Explorer missions successfully detected their presence by detecting the Van Allen radiation belts. By this date most scientist expected to find these particle clouds, and had a solid understanding of the magnetic field that forms them – otherwise, the Explorer spacecraft would not have been designed for the mission of detecting them. Prior to around 1800, few people understood the idea of magnetic fields well enough, I think, to accurately speculate about the Earth having one, though by the late 1800s, after Faraday, Maxwell, and others work, most scientist did.

 

The general public seems to have started becoming aware of the Van Allen belts around the same time as the Explorer missions. As one of the pressing questions answered by these missions was whether a human being could survive a trip into space passing through these clouds of ions, the whole subject had a dangerous feel to it. As more detailed mapping of the belts showed how the magnetic field was interacting with the solar wind, and later missions such as Apollo informed people of how catastrophic exposure to infrequent surges in the solar wind could be to astronauts unprotected a magnetic field or atmosphere, I believe people drew the correct conclusion – that the magnetic field is important – but an exaggerated sense that its failure would leave us as exposed to a solar flare event as an Apollo astronaut.

What info/observations do you have on the solar storm-power grid scenario?

It’s important to clearly describe what happens when a change in the solar wind causes electic power systems to have problems:

• The Sun emits more than the usual number of ionized nuclei (anout 95% hydrogen, 4% helium)
  
• They encounter, and are deflected by the Earth’s magnetic field
  
• Since they have mass, this deflection requires an equal and opposite force. This force accelerates – moves, deforms – the magnetic field, not only its outer field lines, but ones near the surface
  
• The moving magnetic field induces a (lot of) current in any long conductors perpendicular to it, such as high-tension power lines
  
• This extra current, causes power-handling systems to disconnect (trip), or fail to trip and be damaged.
  
• ”Cascades” of failures, power outages, and general woe ensues.
  

A tricky problem to handle, but one on which a lot of clever people are working :lightbulb

[Turtle]

It’s wonderful to see hypography accomplish its purpose of hosting ideas and spreading knowledge. Applause for Eclog, Turtle, and hypography in general!

 

... As more detailed mapping of the belts showed how the magnetic field was interacting with the solar wind, and later missions such as Apollo informed people of how catastrophic exposure to infrequent surges in the solar wind could be to astronauts unprotected a magnetic field or atmosphere, I believe people drew the correct conclusion – that the magnetic field is important – but an exaggerated sense that its failure would leave us as exposed to a solar flare event as an Apollo astronaut....:phones:

 

Thanks Craig, and a tip o' the hat to you as well! Here here Hypography!

I received a reply to one of my E-mails today:

Hi there,

 

check out this article and the links therein:

http://en.wikipedia.org/wiki/Magnetosphere

 

Best regards,

 

Daniel Mueller

 

-----------------------------------------------------------

Dr. Daniel Mueller ([email protected])

SOHO Deputy Project Scientist

European Space Agency c/o NASA Goddard Space Flight Center

The article is helpful & informative, and hats off to these folks for taking the time to reply to a turtle.:) :)

Off to do more reading then. :friday:

[Eclogite]

Thank you Turtle for the offer of sustenance.

 

Please note in all of this:

 

1. I am not disputing that the switching of the poles will have marked effects on the biosphere. I am simply challenging the popular view that it spells widespread disaster, or at least dangerous changes including increased exposure to radiation.

 

We know that several creatures use the magnetic field to navigate. Will geese, for example, now be condemned to mass extinction as they fly north for the winter instead of south (in the Northern Hemisphere)? Probably not. Most animals use more than one navigational trick.

I was reading some research the other day - completely forgotten where. Sorry. - wherein they had disrupted the directional sense of birds by exposing them to a strong magnetic field. The birds headed off in the wrong direction, but reset there magnetic directional sense by the location of the setting sun.

(Incidentally, I don't know what research has been done on humans being able to allign to the Earth's field, but I suspect I can orient within about +/- fifteen degrees of North. However, I may be using other subtle clues - on an overcast day, for example, there is still a hint of the sun's direction.)

 

2. I am also prepared to accept that there might be an increased risk from cosmic rays. However, I have yet to see a single peer reviewed item of research in a reputable journal that claims this, let alone proves it. All I see are the same repetitive remarks in popular science publications and documentaries that the magnetic field protects the Earth. This is what, I suspect, lured you into the same belief. I concede that when the National Geographic says it is so, one is inclined to listen.

 

 

You asked when did this false idea gain currency. I am less certain of CraigD's explanation of this. As I recall the discovery of the van Allen Belts came as a complete surprise. Still, since I was still wearing short trousers at the time, my recollection may be hazy.:hyper: I attribute it to the presumed need by science journalists to make the topic as dramatic as possible.

[Turtle]

I just watched a new Science Channel piece on Venus & ESA's new craft. A mix of Venus facts & past missions as well as data from the new craft. Anyway, they made the comment how the solar wind strips 100 tons of atmosphere from venus every day because Venus has no(weaker than Earth?) magnetic field. Along with this commentary they showed some solar wind measurements taken before orbit entry to test the equipment,

So now I wonder to what degree Earth's magnetic field keeps the atmosphere in place?:confused:

I hope this is new speculation on my part, & not part of the common speculation we have already discussed.:shrug:

[Eclogite]

One of the problems with Terraforming Mars is atmospheric erosion. You could provide an atmosphere by impacting several large comets. However, the solar wind, acting on an unprotected atmosphere on a low gravity planet, would remove much of the atmosphere in a geologically short interval - I have seen estimates as low as 50,000 years.

 

So, there is no doubt that the permanent loss of the Earth's field would be problematic in the very long term. Let's do a quick back of the envelope calculation.

Even though our atmosphere is less dense, and we are further from the sun, let's assume the same loss rate - 100 tons per day.

Consider the loss we would have experienced since the Cambrian

100 tons x 365 days x 550 million years = 2.0 x 10^13 tons

 

Now consider the total mass of the atmosphere

 

First, the surface area of the Earth is given by 4.pi.r^2. (I'll calculate it in square inches for reasons that will become apparent.)

Area = 4 * pi * (4,000*5280*12)^2

= 8.07 x 10^17

 

Air pressure, due to the overlying mass of air, is 14.7 psi.

Therefore, mass of the atmosphere in pounds = 8.07 x 10^17 x 14.7 = 1.19 x 10^19

Mass in tons = 1.19 x 10^19/2200 = 5.39 x 10^15 tons

 

So had we been losing atmosphere to the solar wind, then since the Cambrian we would have lost (2.0 x 10^13/5.39 x 10^15), or 0.4%.

 

I think you'll agree that's not much of a problem.:)

[Turtle]

It’s wonderful to see hypography accomplish its purpose of hosting ideas and spreading knowledge. Applause for Eclog, Turtle, and hypography in general!

 

Let’s be cautious, however, not to conclude that a major decrease in the Earth’s magnetic field would be a minor event. ...It’s important to clearly describe what happens when a change in the solar wind causes electic power systems to have problems:

• The Sun emits more than the usual number of ionized nuclei (anout 95% hydrogen, 4% helium)
  
• They encounter, and are deflected by the Earth’s magnetic field
  
• Since they have mass, this deflection requires an equal and opposite force. This force accelerates – moves, deforms – the magnetic field, not only its outer field lines, but ones near the surface
  
• The moving magnetic field induces a (lot of) current in any long conductors perpendicular to it, such as high-tension power lines
  
• This extra current, causes power-handling systems to disconnect (trip), or fail to trip and be damaged.
  
• ”Cascades” of failures, power outages, and general woe ensues.
  

A tricky problem to handle, but one on which a lot of clever people are working :ip:

 

Earth's magnetosphere aside, we have not only the items you list at risk of solar storms, but satellites as well.

http://space.com/scienceastronomy/060502_solar_storm.html

The implications stemming from a geomagnetic superstorm akin to the one that occurred in 1859 would be economically devastating given our reliance upon satellites. That's the view of Sten Odenwald of the QSS Corporation based at the Goddard Space Flight Center in Greenbelt, Maryland.

:cup: :)

[IDMclean]

Nice Calc's Ecolite. I would wonder however could it be that there are issues with your calculations? As I understand the earth had higher pressure at sea level, way back when. Could it be a reducing problem? Something like Half-life. Where you strip off half and it takes twice as long to strip off the next half? You treat 100 tons as a constant for an inheriently dynamic system.

 

Just somethoughts to think about.

[nkt]

I suspect that the effects will be quite fatal for our way of life, but only until everything reboots. Some of the modern hard disks might develop faults, but this is pretty unlikely. The errors will be due to power outages and spikes, and the odd computer that has not enough shielding will die briefly.

 

I think it will last for about three or four days, hopefully.

 

As regards the increased risk of skin cancer, well, I think going from factor 5 to factor 10 will be enough.

 

Many geese will die, however, as they get upset at being a full 180 out, and some will probably refuse to accept the error.

 

Charged particles like a proton travel a few millimeters in air, for what it is worth. They hit air molecules, and strip off electrons, causing a shower of particles, but, again, they are absorbed within a few millimeters at ground pressures. Flying might become a far more radioactive venture, of course, as the air in thinner up there, and the radiation dose from flying is far higher than on the surface. What that dosage might be with no magnetic shielding, I have no idea.

 

An interesting idea is that the ground/earth (in electrical terms) might change for a while, too. An influx of protons without the electrons to balance it out, might shift the neutral point, until the earth harvests some more electrons from somewhere.

 

Also, CRTs will stop working properly. They are adjusted to compensate for the earth's magnetic field. I'm not sure if degaussing would be enough.

 

How long does it take to switch over, anyway?

[HydrogenBond]

One reversal of the magnetic field shows some similarity to todays global warming. It led to many modern species of plants and animals.

 

A study was made of intermittently produced Miocene lava formations at Steen's Mountain, Oregon, USA, which gave a very detailed picture of both the intensity and directional changes which occurred during a magnetic reversal. The complete reversal took about 4500 years and the average magnetic field at the surface fell to about 20% of normal during the change. The transitional field was typically non-axisymmetric and there was much meandering, even crossing the equator three times. Three geomagnetic impulses occurred which corresponded to high rates of change of the field. The angular rates of change were approximately 50 +/- 20 degrees per year.

 

The Miocene epoch is a period of time that extends from about 23 to 5.3 million years before the present. The Miocene was a time of warmer global climates than those in the preceeding Oligocene, or the following Pliocene. It is particularly notable in that two major ecosystems first appeared at this time: kelp forests and grasslands. Recognizable wolves, raccoons, horses, beaver, deer, camels, whales, etc. existed in the Miocene. Recognizable crows, ducks, auks, and owls appear in the Miocene.

The oceans gradually cooled, and brown algae plants, called kelp, proliferate, supporting new species of sea life, including otters, fish and various invertebrates.

 

What is interesting about the field reversal was the speed at which it was moving around the earth during its transition. This rate can not be explained using the existing magneto dynamics theory. This miocene data is usually ignorred for that reason.

[CraigD]

Also, CRTs will stop working properly. They are adjusted to compensate for the earth's magnetic field.

CRTs and other consumer electronics don’t require compensation for the Earth’s magnetic field. If this were the case, CRTs would have to be adjusted whenever they were moved to point in a different direction of the compass.

 

CRT’s can be affected by magnetic fields, but such fields must be many hundreds of times stronger than the Earth’s. The vicinity of large generators are commonly afflicted with such fields. The effects are usually just an annoying distortion of on-screen images, which can be resolved by moving the CRT farther away from the source of the field. A strong magnet such as one might attach to a refrigerator can also distort the image on some CRTs when placed on them.

[HydrogenBond]

The movement of the earth's magnetic field during the Miocene period was quite impressive. If we assume it moved 30 degrees per year, that is about 2000 miles per year or roughly six mile per day, or about 1/4 mile per hour. It was slowly combing the earth and could be seen moving with the naked eye.

 

This movement rate and its migration change back and forth across the equator would correlate to a very high rate of core convection changes in a relatively short period of time, using dense visco-plastic material. The thermal requirements for such convection changes would imply the earth's core needing to generate a lot of heat. Just plane old gravity just can't cut the mustard. This leaves radioactive decay or maybe even fusion as logical sources of the extra heat. The extra heat needed for the convection also indicates a possible source of global warming at that time was geothermal. The oceans cooled after the reversal.

[DougF]

Very good thread thanks for the research and links.;)

one question though. :phones:

HydrogenBond

The movement of the earth's magnetic field during the Miocene period was quite impressive. If we assume it moved 30 degrees per year' date=' that is about 2000 miles per year or roughly six mile per day, or about 1/4 mile per hour. It was slowly combing the earth [b']and could be seen moving with the naked eye.[/b] [/Quote]

How would this be visible to the naked eye? :shrug:

[aquamarinegreen]

Yes the earths magnetic poles have switched over many times during its long history - look at the magnetic map of the sea floor in the atlantic to see the mirror image reversed polarity on either side of the mid atlantic ridge where the new sea floor is made. It seems to be a property of the way the magnetic field is generated within the earths liquid core - the polarity randomly reverses!

[Moontanman]

I just started leaning about magnets at school and came across and interesting fact, Earths magnetic field changes! It has been proved that the magnectic field has frequently switched so that our north pole was south and vise versa, the next interesting part is that we are due for another change in the next 1000-2000 years

this is bad news because earths magnetic field protects us from a lot of the suns harmful radiation... but im sure we can come up with an alternate solution when push comes to shuv

 

 

We don't really know how long the switch takes, some studies have indicated a possibility of very fast shifts others seem to show a slow shift. Radiation danger would depend on how fast the switch was. As long as it wasn't more than a century I don't think we would have to worry. The real danger is our atmosphere being blown away, that don't happen overnight but it could be significant if the change takes thosands of years. our atmosphere protects us like several inches of lead or maybe it's feet i can't remember the quote. Mars dosn't have much atmosphere because it has very little if any magnetic feild. It might have had one at some time but that was long ago.

 

Michael