New Study of Reversals of Earth's Magnetic Field

[littlemissattitude]

This, from CNN, is interesting, similar to but not quite the same perspective as the BBC article posted by Brian in January.

-- Next time Earth's magnetic field flips, compass needles will point South instead of North. But scientists can't say when it will occur, and until now they've disagreed on how long the transitions take.

A new study pins down how long it took for the last four reversals to play out. It also finds that the dramatic turnarounds occur more quickly nearer the equator than at higher latitudes closer to the poles.

That means folks living during the next reversal -- which some scientists speculate might be underway -- will see compasses change and behave differently in different locations, said study leader Brad Clement of Florida International University.

http://www.cnn.com/2004/TECH/space/04/07/poles.reverse/index.html

Apparently, they've determined that it takes about 7,000 years for the earth's magnetic field to reverse polarity, but that it doesn't happen at the same rate everywhere on earth - it's quicker at the equator.

Also, the reversals don't happen at regular intervals. During the past 15 million years there have been an average of 4 reversals every million years, or about once every 250,000 years. The most recent reversal, however, was 790,000 years ago. So, we may be overdue for one - or not. And some say that we are in the early stages of a reversal.

 

[BAYLOR]

This reversal will wreak havoc with the atmosphere and could men a diminishment of Ozone protection for a time .

 

[Vertigo]

I believe the bigger worry is more to do with the magnetosphere than the ozone. During the transition, as I understand it, the magnetosphere will be almost negligible which means we will be massively more exposed to loads of bad stuff! At least now with GPS we're less dependant on magnetic compasses - of course that assumes our satellites can survive the experience. However I would expect them to on the basis that a reversal takes thousands of years so plenty of time to harden them as things progress.

The compass issue is already a problem in some locations simply because of the presence of magnetic rocks. If I try to use my compass on the Cuillin hills on the Isle of Skye then I really have to take a 'average' as I walk along as the needle will hop around all over the place as you walk.

 

[BAYLOR]

I believe the bigger worry is more to do with the magnetosphere than the ozone. During the transition, as I understand it, the magnetosphere will be almost negligible which means we will be massively more exposed to loads of bad stuff! At least now with GPS we're less dependant on magnetic compasses - of course that assumes our satellites can survive the experience. However I would expect them to on the basis that a reversal takes thousands of years so plenty of time to harden them as things progress.

The compass issue is already a problem in some locations simply because of the presence of magnetic rocks. If I try to use my compass on the Cuillin hills on the Isle of Skye then I really have to take a 'average' as I walk along as the needle will hop around all over the place as you walk.

The Radiation issue could force us to move underground for a time, for purposes of survival.

 

[Vertigo]

It is conceivable I guess but I think it most likely that we'll have to wear something similar to the mega sun block stuff that the Aussies still (I think) have to wear when outside. I'm not sure it would be quite so bad that we would have to take such drastic action otherwise we'd see major evolutionary shifts, genetic mutations and outright extinctions in the fossil record from previous polarity shifts.

Edit: ...and probably have to be very alert to solar flare events.

 

[BAYLOR]

It is conceivable I guess but I think it most likely that we'll have to wear something similar to the mega sun block stuff that the Aussies still (I think) have to wear when outside. I'm not sure it would be quite so bad that we would have to take such drastic action otherwise we'd see major evolutionary shifts, genetic mutations and outright extinctions in the fossil record from previous polarity shifts.

Edit: ...and probably have to be very alert to solar flare events.

Sunblock 10,000 and protective suits might be the order of the day. This will likely put the beach going and the bathing suit industry out of business.

On a more serious note,this could impact food production and could lead to the extinction of species on land , though not so much in the seas but even there there will be disruptions of the plankton cycle.

 

[Vertigo]

Most certainly some problems but as I said I'm not aware of any significant increase in extinctions during previous reversals (Wiki says "Statistical analysis shows no evidence for a correlation between reversals and extinctions"). But I'm sure that if there had been the media would have leapt on it and this idea has been around for quite some time. There was a documentary about it in the UK some years ago (Horizon maybe?) and I seem to recall their biggest concerns were sunblock and the impact on our growing dependence on high tech that may be seriously affected. I also seem to recall them mentioning that it might create some spectacular visual effects in our skies but can't remember the exact reasons.

 

[Stephen Palmer]

There was a documentary about it in the UK some years ago (Horizon maybe?) and I seem to recall their biggest concerns were sunblock and the impact on our growing dependence on high tech that may be seriously affected. I also seem to recall them mentioning that it might create some spectacular visual effects in our skies but can't remember the exact reasons.

That was a good documentary.

The spectacular visuals would occur if there were more than two poles during the crucial stages of a reversal - there could be four, or even eight. Then you'd get aurora at all latitudes, not just at the poles.

 

[Venusian Broon]

Sunblock 10,000 and protective suits might be the order of the day. This will likely put the beach going and the bathing suit industry out of business.

Mmmmm not quite the right angle on what protection we'd need...we'll still have an ozone layer (although see thoughts later) blocking the harmful UV rays, hence the sunblock is unnecessary. The problem will be the solar flares and cosmic rays that will reach the surface and sun tan lotion isn't designed for energetic particles. A layer of aluminium foil might be enough to stop solar particles, as these aren't too energetic...but cosmic rays are another matter altogether. We'd become a (higher risk) cancer planet. However, I don't know if that means we should be living deep underground. Actually I wouldn't be surprised if it isn't too bad just to continue living on the surface.

The most immediate problem however will be that our surface electronics - anything that isn't hardened will be likely be shorted and loads of power outages due to solar flares. One presumes that is is theoretically possible to harden the whole of our power and electronic grids and life...but think of the cost!

Yes, if the lack of a magnetic field carries on for a while, then more and more of our atmosphere will be broken up and ejected into space. So perhaps this will 'push out' our ozone layer. But then again it may remain at strength - as long as there is oxygen in the atmosphere and a sun shining on it, ozone will be produced. I believe there is no clear idea what would happen to the ozone layer - would a big solar flare be able to push it to one side? Who knows.

However on the plus side - the magnetic field seems to flip 4-5 times every million years and in the big general scheme of things life on Earth seems to have taken it in its stride.

I think there are much worse nightmare scenarios that trump this one.

 

[Vertigo]

That was a good documentary.

The spectacular visuals would occur if there were more than two poles during the crucial stages of a reversal - there could be four, or even eight. Then you'd get aurora at all latitudes, not just at the poles.

That's right I remember now; multiple poles + aurora!

Mmmmm not quite the right angle on what protection we'd need...we'll still have an ozone layer (although see thoughts later) blocking the harmful UV rays, hence the sunblock is unnecessary. The problem will be the solar flares and cosmic rays that will reach the surface and sun tan lotion isn't designed for energetic particles. A layer of aluminium foil might be enough to stop solar particles, as these aren't too energetic...but cosmic rays are another matter altogether. We'd become a (higher risk) cancer planet. However, I don't know if that means we should be living deep underground. Actually I wouldn't be surprised if it isn't too bad just to continue living on the surface.

The most immediate problem however will be that our surface electronics - anything that isn't hardened will be likely be shorted and loads of power outages due to solar flares. One presumes that is is theoretically possible to harden the whole of our power and electronic grids and life...but think of the cost!

Yes, if the lack of a magnetic field carries on for a while, then more and more of our atmosphere will be broken up and ejected into space. So perhaps this will 'push out' our ozone layer. But then again it may remain at strength - as long as there is oxygen in the atmosphere and a sun shining on it, ozone will be produced. I believe there is no clear idea what would happen to the ozone layer - would a big solar flare be able to push it to one side? Who knows.

However on the plus side - the magnetic field seems to flip 4-5 times every million years and in the big general scheme of things life on Earth seems to have taken it in its stride.

I think there are much worse nightmare scenarios that trump this one.

Agreed It's happened many times before so biologically I think we'd survive, if, as you say, with a higher cancer risk. And with the timespan of a reversal I think we'd get the hardware sorted!

 

[Dave]

The problem will be the solar flares and cosmic rays that will reach the surface and sun tan lotion isn't designed for energetic particles. A layer of aluminium foil might be enough to stop solar particles, as these aren't too energetic...

Are you saying we need to wear tin foil hats!

 

[Venusian Broon]

And with the timespan of a reversal I think we'd get the hardware sorted!

And if you are with Virgin media, you wouldn't even notice the difference that the outages make!

 

[Venusian Broon]

Are you saying we need to wear tin foil hats!

This is a bit off-topic, but talk of tinfoil hats reminds me of one of my favourite scientific papers, namely the great: On the Effectiveness of Aluminium Foil Helmets: An Empirical Study...

See http://mozai.com/writing/not_mine/aluminium_helmets_research.pdf

As you can see from the abstract they come to some interesting conclusions....okay, it might have been a little spoofed up

 

[BAYLOR]

Are you saying we need to wear tin foil hats!

And what's wrong with tin foil hats? Without mine, I wouldn't be able to come up with topics and my witty repartee would be much diminished . Your also forgetting that some of history's greatest minds wore tin foil hats.

Of course during lighting storms I do have to remember to take mine off.