Dispelling Myths About Geomagnetic Reversal

UniverseToday has an interesting look at geomagnetic reversal, the process in which the Earth's magnetic poles trade places. The article cites known trends and recent studies to debunk doomsday myths and unsubstantiated claims about the process. One such study is attempting to model the earth's core with a 26-ton ball of molten metal. Another recently found evidence that the Earth has a second, weaker magnetic field. "We do know that this magnetic pole flip-flop has occurred many times in the last few million years; the last occurred 780,000 years ago according to ferromagnetic sediment. A few scaremongering articles have said geomagnetic reversal occurs with 'clockwork regularity' — this is simply not true."

Comments

Comment removed

[account_deleted]

Comment removed based on user account deletion

Re:Not really worried.

[jcorno]

The only reason I'd really be worried about the magnetic field flipping is that a changing magnetic field induces a current in a conductor. This means every electronic and electrical device with a closed loop would experience a large current, likely destroying the smaller equipment.

The earth's magnetic field is about half a gauss at the surface. It's weaker than the field generated by a refrigerator magnet. I think it's safe to say that the flip is not gonna destroy your electronics.

Re:It's all hopelessly out of date!

[Anonymous Coward]

That's utter nonsense. The magnetic field is continuously monitored from orbit by all sorts of satellites. One of many such satellites is Ørsted. There are papers all through the 1990s and 2000s that analyze the data from this and the others. People don't fund surface expeditions to study large-scale magnetic field variations because they've been largely superceded by satellite measurements. The only people interested in surface measurements are usually exploration geologists (e.g., looking for signs of sub-surface mineral deposits).

Don't worry

[mangu]

why is this a cataclysm?

It really isn't. The problem itself is not the reversal itself, but the period inbetween, when the magnetic field will be very small or inexistent. The earth's magnetic field has the effect of diverting charged energetic particles emitted by the sun towards the poles. It's those particles entering the atmosphere that cause the northern lights. Without a magnetic field, they would penetrate more into the atmosphere, possibly causing harm to living beings.

However, this reversal will happen several hundred years from now. By that time, I'm sure that, if I'm alive, it will be because we will have some pretty advanced medicine, capable of handling the increased radiation effects.

Re:Don't worry

[mangu]

I still think cellphone antennas can affect more in this cancer matter than something that has happened before in Earth with no big impact at all

Cell phones transmit at a relatively low frequency, which is called "non-ionizing".

Electromagnetic radiation is transmitted by particles called photons, each of which carry a fixed amount of energy, proportional to its frequency. Therefore, to transmit a given amount of power, it takes more low-frequency photons than high-frequency ones. There is a certain frequency, higher than what cell phones use, where the energy of a single photon is enough to break the chemical bonds that keep molecules together, that's what is called "ionization".

At lower, "non-ionizing" frequencies, you can send as much power as you want, you may cook the tissue, but the chemical bonds will not be broken in the same way, because the photons don't have the required energy.

The sun emits particles in a very wide range of energies, including ionizing ones. The charged particles with ionizing energy which are diverted by the earth's magnetic field are certainly more dangerous than any cell phone antenna.

The dangers of non-ionizing radiation have been the subject of debate, but one should be careful when judging the data. With high enough power, like in a microwave oven, there will be damage to living tissues, of course, but it's in an entirely different level from ionizing radiation, where a single photon is enough to break a molecule and, pick your worse nightmare, start a cancer or cause a mutation.

Re:Best quote ever

[Anonymous Coward]

I build the navigation systems used in many commercial aircraft. Primary system is inertial, not GPS; input from multiple accelerometers is integrated to determine velocity and position.

4 * 10-13 Hz

[S-100]

I don't think a field change at .0000000000004 Hz is going to induce much current anywhere.

TFA does little to debunk what may be the biggest danger, and that is the disruption of the Van Allen radiation belt, and the protection that it provides to the Earth from cosmic rays. While I'm sure that the radiation belt would re-establish itself to match the "flipped" magnetic poles, it may not do so during the transition period. And this pole flipping may be quick in geological terms, but it may take a number of years, and during that time, part or all of the Earth may be bombarded with cosmic rays. Or, the distorted field may actually concentrate cosmic rays upon parts of the Earth many times what you'd find in space outside the belt. These cosmic rays would cause massive increases in cancer and genetic mutations in all species of plants and animals, and even a stack of tinfoil hats won't help. Much.

Increases in cancers would not be detected in the geological records, and periods of high radiation may explain things like the Cambrian Explosion, where many new species spontaneously appeared. If the field swaps by rotating from pole to pole, the radiation belt will probably just follow along, but if the poles swap by diminishing to zero and then building at the opposite pole, there will be a very dramatic change (and possible collapse) of the radiation belt that could very well affect life on the planet very dramatically (from our perspective). The scourge of AIDS killed 2.1 million people in 2007. That's .03% of the world population. Just a doubling of the current rate of death due to cancer would kill 7.9 million people - almost four times that of AIDS. And with sufficient radiation exposure, the cancer rate could well escalate way beyond 2X.

Of course, ancient calendars not withstanding, there's no reason to believe any of this is likely to happen during our lifetimes.