Solar Winds to Protect Earth During Magnetic Pole Reversal

me98411 writes "A study published in April, hinted at possible anamolies/reversal in Earth's magnetic field. This study found that there is an anamoly in a large patch near South Africa where the Earth's magnetic field points in the opposite direction. Now, according to New Scientist, this planet might be safe during reversal of poles due to formation of replacement field created by interaction with solar winds. Phew! I was worried I will not be able to use my compass." Even better than compasses not being obsoleted, we won't be bombarded with dangerous levels of radiation, or so the scientists say.

Comments

So Lemme Get This Straight....

[Wandering Wombat]

The solar winds, which are charged particles being moved by solar radiation, will prevent us from being hit with charged particles and solar radiation?

Re:So Lemme Get This Straight....

[Jerf]

No, the interaction with the solar wind and the atmosphere will prevent us from being hit with charged particles.

Solar electromagnetic radiation comes through no matter what and is not affected by the magnetic field. In fact, that's something of a similar situation: The Ozone layer, as I understand it, is formed by the very radiation it absorbs. That's why a hole in the Ozone layer forms over the pole that gets no sunlight; Ozone breaks down relatively quickly and without the production mechanism, eventually it all breaks down. It reforms again once it is hit by sunlight again. CFCs were theorized to accelerate the destruction rate of the ozone, which caused a net reduction in the amount there was, starting near the poles since they get less sunlight and already had a lower production pace.

In the reverse direction, note that shielding can sometimes cause a net increase in dangerous radiation, as high-energy cosmic rays that would just pass through a person impact the shielding and bombard the shielded thing (like a person) with a series of lower energy radiations, which may total a lower energy overall then the cosmic ray but have a much greater effect on the person.

Second-order effects very often swamp the first-order effects. This is one of those basic facts of mathematical thinking that is vital to understanding any sort of science, and is one of the reasons having politicians, and people who think they understand science but don't understand this kind of mathematical thinking, scare me so much. Statements like "Higher taxes mean more income", "more shielding means less radiation", and "a lower magnetic field means more radiation getting to the surface" may all sound like common sense, but they aren't; the former two are certainly not universally true (only true under certain circumstances, which if you don't understand the limits you will almost certainly be led astray), this article suggests that the same is true of the third.

It's only confusing if you insist on trying to understand everything solely in terms of their first-order effects; the universe is far, far from that simple.

That said, I have no idea if this simulation is correct or not; I merely observe that there's no reason to dismiss it because it contradicts the results of a simplistic analysis based soley on direct effects.

(Minor nit: The solar wind is simply charged particles streaming away from the sun; they are not necessarily being moved by "solar radiation", which is really too generic a term in this context to be useful.)

Re:So Lemme Get This Straight....

[PurpleFloyd]

Because a map and decent compass don't cost more than about $25, require batteries, die when they get wet (you can easily get waterproof maps), or lose signal under heavy cover.

I use GPS when I go hiking, but I would never trust it with my life; my compass, on the other hand, has been dropped, stepped on, crushed and generally ill-treated for about 15 years and has served me faithfully through all that time (although I have had to adjust the declination after a few of the really rough treatments). GPS is an incredibly useful tool, but it's never a good idea to trust your life to something whose batteries might go dead on you, especially when an excellent backup is easy to use, weighs only a few ounces, and can be had cheaply.

Re:So Lemme Get This Straight....

[gumbi west]

...note that shielding can sometimes cause a net increase in dangerous radiation, as high-energy cosmic rays that would just pass through a person impact the shielding and bombard the shielded thing (like a person) with a series of lower energy radiations, which may total a lower energy overall then the cosmic ray but have a much greater effect on the person.

Nice try, but according the the United Nation's report on the sources and effects of radiation, the dose rate is higher for pilots who fly over regions of lower magnetic field strength (look at the section on ocupational exposure). Lower magnetic field strength occurs near the magnetic poles, and is where lower energy particles can penetrate the magnetic field (areas of lower geomagnetic cutoff).

Also, according to a paper in materials science research titled, Cosmic-Ray Neutrons on the Ground and in the Atmosphere And a number of other papers by the same author, the measurements show that the cosmic contribution to background dose rate increases as the strength of the magnetic field decreases.

The error in logic with your argument is that the magnetic field deflects particles before they reach the atmosphere and interact. Once they reach the atmosphere, they interact with the atmosphere (not the magnetic field) to generate the "more dangerous radiation." as you call it. That said, I'm not entirely sure that this radiation is any more or less dangerous. While it is true that the quality factor is lower (what you multiply the energy deposion by to get the increased quantity that is proportional to increased probability of cancer), the energy deposition can be higher (this is true for photons, but not electrons, and I just don't know for protons and higher Z charged particles with kinetic energies in the GeV range).

Re:So Lemme Get This Straight....

[sethanon]

You're using a once in a million years event (albeit one that may last for a thousand years) to claim that compasses aren't reliable?

I suspect that if I go hiking tomorrow there is more chance of my GPS unit screwing up than the earth's magnetic field suddenly vanishing.

The real point of the post you are replying to is: if you are going to stake your life on a piece of equipment, make sure you have a backup. Preferably something that has different failure modes.

Good slides from UW Aeronautics and Astronautics

[joelparker]

Good lecture slides on solar events in PDF
are from the Aeronautics and Astronautics
group at the University of Washington.

They also have nice slides on airplane/spacecraft design,
also in PDF here

What does the fossil record show?

[beeplet]

Records of the field direction, frozen into sediments laid down on the seabed, show that the magnetic field has reversed hundreds of times in the past 400 million years.

I would have thought that that alone would indicate that field reversals are not exactly "disasterous" for life on Earth. Poor for human health, maybe, but it's not like we're facing mass extinction.

Actually, given that they're apparently able to identify eras of field reversal in the archeological record, I wonder if anyone has tried to correlate it with periods of extinction or rapid evolution? That would be more interesting to me - at least better than all of the speculation that seems to be going around.

Re:What does the fossil record show?

[bcrowell]

I would have thought that that alone would indicate that field reversals are not exactly "disasterous" for life on Earth. Poor for human health, maybe, but it's not like we're facing mass extinction.
I don't think it's that easy to read the fossil record and apply it to our situation. A species could easily get its population knocked down to 1/1000 of its former value, then recover over the course of a few centuries, without ever leaving a detectable trace in the geologic record. Also, it's often unclear why one species survived a mass extinction event while another went extinct, e.g., nobody knows why alligators and crocs survived the event that killed off the dinosaurs.

Actually, given that they're apparently able to identify eras of field reversal in the archeological record, I wonder if anyone has tried to correlate it with periods of extinction or rapid evolution?
I'm not a biologist, but IIRC, radiation-induced mutations are not a major driving force behind evolution. I think most evolution occurs simply by reshuffling the preexisting genes. And remember, there are plenty of chemicals in the environment that are mutagens. If radiation was a big factor driving evolution, it would be hard to understand most of the evolutionary history of life on earth, since most life on earth isn't terrestrial, and the nonterrestrial stuff (fish, underground bacteria,...) is shielded from radiation that comes from space. (Some radiation comes from the earth itself.) A lot of radiation doesn't penetrate very deeply, either, so it's a lot more likely to give you skin cancer than to mutate your sperm or egg cells.

BTW, I believe there was no measurable increase in mutations among the kids of the Hiroshima and Nagasaki survivors.

Worried about your compass?

[jgaynor]

"Phew! I was worried I will not be able to use my compass."

Oh yeah! I forgot about my compass not working! Silly me - I was too busy thinking about the possible massive upsurge of CANCER . . .

Re:Worried about your compass?

[Anonymous Coward]

I was too busy thinking about the possible massive upsurge of CANCER

Doesn't affect me, I'm a Capricorn.

Re:Bush is to blame!

[Anonymous Coward]

Bush and the Republicans are to blame for this!

Nice joke, but were you aware of the huge stack of magnets Bush is having set up at the science station on the south pole? He has errected a giant stack of iron-ferrite magnets a mile high with a magnetic field opposite to that of the Earth. Every day it gets higher. Apparently he is trying to speed up the reversal process, because it is rumored that durring a field shift special instruments can be used that make it easier to locate huge oil deposits under the earth, and these instruments are usually rendered useless by the Earth's magnetic field.

Just food for thought.

Re:Don't buy compass stock just yet...

[Teancum]

Mars does indeed have a significant magnetic field, it is just that it has several dozen north and south poles, which is the current theory about what will happen during the transition phase when the poles switch:

At first the poles weaken in strength.

New "North" & "South" poles start to appear in strage places, like in equatorial regions.

For a geologically brief period of time there are dozens to hundreds of magnetic "poles" scattered throughout the planet.

Eventually the number of poles start to drop, and the new magnetic "North" & "South" poles become more established and start to gain more strength. At this point the reversal is complete.

Mars appears to have gone geologically dead during the middle of one of these pole reversals, so Mars is also being used to provide a "snapshot" as to what the Earth might be like in the next 500 years.

Nova recently had a show about this!

[GooberToo]

http://www.pbs.org/wgbh/nova/magnetic/