Earth's Magnetic Field Weakens 10 Percent

caryw writes "Interesting story from the AP. 'The strength of the Earth's magnetic field has decreased 10 percent over the past 150 years, raising the remote possibility that it may collapse and later reverse, flipping the planet's poles for the first time in nearly a million years, scientists said Thursday. At that rate of decline, the field could vanish altogether in 1,500 to 2,000 years, said Jeremy Bloxham of Harvard University. Hundreds of years could pass before a flip-flopped field returned to where it was 780,000 years ago. But scientists at a meeting of the American Geophysical Union cautioned that scenario is an unlikely one. "The chances are it will not," Bloxham said. "Reversals are a rare event."'"

Comments

Wasn't this on PBS?

[Micro$will]

Or was it Discovery channel?

Apparently this is supposed to happen every 600,000 years. During the flip everyone on Earth will be exposed to elevated levels of cosmic/solar radiation increasing the chances for cancer. The good news is we'll have multiple auroras all over the planet as the fields move around.

Re:Wasn't this on PBS?

[Adam_Trask]

You're right. I saw it on PBS.
Nova has made a nice documentary abt this.

Not weakened 10%!

[Anonymous Coward]

The north-south polarity may have weakened 10%. The totality of the field remains the same. The north-south polarity appears to be randomizing as it realigns into a south-north flip.

Why should we care?

[Coppit]

Losing the magnetic field would cause some big problems. First, the magnetic field acts as a shield which diverts the solar wind to the poles. (That's the aurora we see.) I don't know about you, but I don't want to wear sunblock every day.

Second, much of our electronic communications would be interrupted without this protection. For more information see this FAQ

Re:Why should we care?

[barakn]

I think there's a problem with those high energy protons destroying ozone (mentioned in TFA), so sunblock might be necessary. And even if the total field doesn't weaken, during the reversal the dipole moment of the field will, leaving quadrupoles or octopoles or something. A magnetic field parallel to the ground is a good shield against charged particles, but a perpendicular field (a pole) actually guides charged particles towards the ground, hence phenomena such as aurora. If a pole erupts in my neck of the woods, I'd seriously consider moving elsewhere. Or dust off the ol' tinfoil hat and put it on.

Didn't we already discuss this ?

[freuddot]

Magnetic Poles May Be About To Flip.

So, all the discussions about end-of-the-world, and creating our own magnetic field are already available there. ;-)

J.

There was a great Nova about this

[michaelggreer]

It was called "Magnetic Storms." A little sensationalistic, but it does appear that we are a few millennia overdue for a flip. A flip is preceded by just this kind of drop in magnetic force, as "islands" of positive polarity start appearing in the negative area and visa-versa. Already a big one near Antarctica.

Take a look at the website. It has a great video of a simulated flip. Scary stuff.

Uh, very convincing

[Hamster Lover]

First, there is overwhelming evidence that the dipole component of the magnetic field has diminshed, reversed and strengthened only to diminish and reverse again many times.

Second, the measured dipole field strength is only one component of the total field strength. Extrapolating the age of the earth based on the dipole field strength alone is not based on any accepted science.

"Scientific" Creationists like to believe that they're using science to support their theist assertions, but that is just the problem. Science does not presuppose any conclusion and is effectively neutral any subject until logic, reason and experimentation point the way.

Re:all hands abandon convention!

[JonMartin]

well, do you care much at all about which way around the toilet your water swirls as it goes down the drain? of course you don't -- and it's a good thing because if you cross the equator and flush your toilet again, the water will go down the other direction.

Um, no.