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Magnetic Field Reversals Unlikely To Be a Problem For Life, Says Astronomer (arxiv.org)
RockDoctor writes: A common trope in "the world is going to end, maybe tomorrow" alarmism is the prospect of the earth undergoing one of its frequent (but aperiodic) magnetic field reversals. Popular conceptions have migrating birds falling out of the sky, satellites and GPS systems no longer working, and much other such silliness. Of course, geologists point out that it has literally all happened before, that there is no significant association of extinction with reversals, and that what evidence there is points to a reversal taking a number of centuries to millennia to achieve. And then the next story comes out and the same old "sky is falling" garbage comes out again.
Just for a change, an astronomer has thrown in his few cents worth. In a letter to The Astrophysical Journal (Warning: source paywalled; alternative source), Manasvi Lingam of Harvard University looks at the implications of a magnetic reversal, or of the "switching on" of the Earth's "dynamo" on the flux of radiation experienced by an organism living near the surface. Lingam deduces that during a reversal (or before the dynamo started) "neither the biological radiation dose rates [...] would vary by more than a factor of 2." Behind the "..." is a prospect which will appeal to those looking for ways to die, as "the atmospheric escape rate" is also somewhat affected by the strength of the magnetic field. As a theoretical astronomer, Lingam agrees with the geological record (yay!) that field reversals are unlikely to have major effects on life, or on the atmosphere, or really, on anything other than astronomers' and geophysicists' gauges and dials. None of this will even slightly slow down the overblown hysteria that accompanies the next twitch of the magnetic field.
Just for a change, an astronomer has thrown in his few cents worth. In a letter to The Astrophysical Journal (Warning: source paywalled; alternative source), Manasvi Lingam of Harvard University looks at the implications of a magnetic reversal, or of the "switching on" of the Earth's "dynamo" on the flux of radiation experienced by an organism living near the surface. Lingam deduces that during a reversal (or before the dynamo started) "neither the biological radiation dose rates [...] would vary by more than a factor of 2." Behind the "..." is a prospect which will appeal to those looking for ways to die, as "the atmospheric escape rate" is also somewhat affected by the strength of the magnetic field. As a theoretical astronomer, Lingam agrees with the geological record (yay!) that field reversals are unlikely to have major effects on life, or on the atmosphere, or really, on anything other than astronomers' and geophysicists' gauges and dials. None of this will even slightly slow down the overblown hysteria that accompanies the next twitch of the magnetic field.
All stars end up as iron, as it's the lowest energy state that can neither be fused nor fissioned.
A star usually fuses its elements in a chain, and a fraction always ends up as iron, by the time it explodes.
Our sun is not the first generation.
So the cloud it formed in, also contained some iron.
And from that cloud came our planet.
That alone would not be enough.
The key factor is, that it is liquid. Allowind the poles of the iron atoms (and everything else) to line up, at least regionally.
Add spinning, forces from other large bodies and varying levels of liquidity, and you get quite a bit of sloshing stirring chaos in there.
The pole emerges form most polar material lining up.
But of course it isn't precise, and changes all the time in that big mess of poles and smaller poles and arcs and twisting.
And once in a while, the main pole gets so disturbed, that it splits. Then you have multiple smaller poles, and a useless compass.
It takes some time to align into something we and the birds consider useful again.
I have had to use a compass, in the Lake District, in the snow, on my own. Not the cleverest thing to do. There were five paths going away from a cairn so I too a compass bearing from the map. Unfortunately 72 deg leaves a lot of ambiguity and I ended up walking into the wrong corrie (cirque) as tarns can look very similar in the snow. It was only when I got half way down that I realised that "those peaks shouldn't be visible from here".
I'm reminded of similar statements by scientists that an EMP or another Carrington event will have minimal effects on humans or animal life. In both cases (and in this), the problem isn't the direct effects, it's the secondary ones. An EMP will mostly pass through biological tissue just fine, and might not even permanently disable some older cars -- but if the US is out of power for 14 months because no one can get the transformers rebuilt, that particular aspect doesn't really matter, now does it?
For a pole flip, I'm not really concerned about the biosphere (except maybe birds), for precisely the reasons indicated. Rather, how does a magnetic flip affect GPS? Compasses? Does it induce current in the process of the flip? That sort of thing.
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