Download Magnetic Storms Video Note Skeleton

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Magnetic Storms Video Note Skeleton
The earth’s magnetic field is what makes our compasses point north.
Recently, scientists have detected a dramatic change in the earth’s magnetic field.
It seems the earth’s magnetic field is rapidly fading.
The earth itself is a gigantic magnet.
The magnetic field is created deep in the earths core. It streams out near the south pole,
loops around the planet and then runs back into the core near the north magnetic pole.
Today, Mars has no overall magnetic field, but the satellite also dectected signs
indicating that that had not always been the case.
If molton rock cools in a strong magnetic field, iron based minerals can
The fact that there was magnetism in the martian crust proved that when the lava
first erupted mars must have had a global magnetic field.
Like volcanic rock, clay contains tiny pieces of an iron based mineral called
magnetite.
As regions reform, they align with earths mag field.
With millions of tiny magnets all pointing in the same general direction, the pot
itself becomes slightly magnetic.
So its really currents inside the earths liquid metal core that we think gives rise to
the magnetic field.
Scientists believe that just as the electric currents produce the magnetic field so the
magnetic field produces the electric currents.
Every layer of lava contains a record of the magnetic field at the time of that
eruption.
There have been many fluctuations of the fields strength.
Today the earth’s magnetic field runs from south to north which is why compass
needles point toward the north pole.
At some point, the entire global magnetic field had done a sudden, 180 degree flip
completely reversing direction.
Scientists found more and more reversals, On average 1 reversal every 200 thous years.
Whenever the earth’s magnet field reversed direction, the magnetic intensity was
very weak.
Beneath the south atlantic, Jeremy has found clear evidence for a region of magnetic
anomalies places where the field has already started to reverse, and these anomalies are
growing.
In a region of the core 2000 miles beneath the south atlantic, the magnetic currents
have reversed direction, canceling out the main field causing its strength to decline.
Radiation at ground level increases as well.
One estimate is that our overall exposure to cosmic radiation will double and in some
places it could be even worse.
Today, the magnetic field focuses space radiation toward the far north and south
where few people live. But as the main field collapses, the weak field that is left will
have a more complex structure.