The Core 2: This Time It's Not Just a Crappy Movie

[livius drusus]

Okay, so my title may be a tad sensationalistic, but it does look like the magnetic field of the earth is collapsing again. I knew it reversed every million years or so, but I can't say I've ever thought about what the practical consequences of that reversal might be.

Here's an interesting NYT article on the subject: Will Compasses Point South? (http://www.nytimes.com/2004/07/13/science/13magn.html?ei=5006&en=b69c1088848a1e21&ex=1090382400&partner=ALTAVISTA1&pagewanted=print&position) I particularly enjoyed the long, thoughful analysis of the possible effects throughout the article compared to the rather wry description of the movie.

A reversal could knock out power grids, hurt astronauts and satellites, widen atmospheric ozone holes, send polar auroras flashing to the equator and confuse birds, fish and migratory animals that rely on the steadiness of the magnetic field as a navigation aid. But experts said the repercussions would fall short of catastrophic, despite a few proclamations of doom and sketchy evidence of past links between field reversals and species extinctions.

vs.

In March 2003, "The Core," a Hollywood film, gave a wildly exaggerated portrayal of what would happen if the field vanished. People with pacemakers fall dead. Pigeons fly into people and windows. And the planet, a scientist warns, will fry in a year.

He he...

[Dingfod]

Not to mention all the lost Boy Scouts...


I can understand that power grids might suffer a temporary shutdown during the transition, but how on earth ;) could a polarity reversal hurt astronauts and satellites? I thought magnetic field polarity reversals were linked to ice ages.


Warren

[Hugo Holbling]

Sometimes the field weakens without reversing and there is no evidence currently to suggest that a reversal is inevitable. There is also no indication that the effects will be harmful since the change takes so long to occur; indeed, the available historical record suggests no lasting impact.

The field itself is not dipolar and it is likely that the more complex components will compensate for the dipole shift. The associated idea that the field will reach zero in one to two thousand years is interpolated linearly from dipole strength, but the other components are actually increasing. Moreover, the assumption that the rate of decrease is constant appears to be false.

Since the event, if (or when) it comes, would be gradual, animals will be able to reorient themselves over generations. The same would apply to the other predictions made. As i understand it, the present dipole moment is higher than it has been for many thousands of years, so guessing what will happen next is probably better applied to the lottery numbers.

Of course, i could be wrong.

[Corona688]

Not to mention all the lost Boy Scouts...


I can understand that power grids might suffer a temporary shutdown during the transition, but how on earth ;) could a polarity reversal hurt astronauts and satellites? I thought magnetic field polarity reversals were linked to ice ages.


Warren (wild guess) Radiation? The earth's magnetic field is responsible for deflecting a lot of harmful radiation, if the poles reversed there could be a brief interval in which it is not doing that function.

big magnetic fluxes could also harm electronics in satellites directly, by inducing large currents in them. That's how solar flares interfere with power, I believe; they bend the earth's magnetic field as if it's being blown on by a strong wind, and the change in flux induces large currents in long conductors such as power systems.

[Paul H.]

I bet we will never see a movie this good, based on Science, that bad.

It's cool, just because of that.

[livius drusus]

I think The Day After Tomorrow might just take that prize for me. I love every ludicrous minute of it.

[Ensign Steve]

A reversal could knock out power grids, hurt astronauts and satellites, widen atmospheric ozone holes, send polar auroras flashing to the equator and confuse birds, fish and migratory animals that rely on the steadiness of the magnetic field as a navigation aid. But experts said the repercussions would fall short of catastrophic, despite a few proclamations of doom and sketchy evidence of past links between field reversals and species extinctions.

I read that as "aereolas". :giggle:

PS: I haven't seen The Core but I lurved The Day After Tomorrow.

[MonCapitan2002]

I never saw either movie in their entirety. I think they are both rubbish.