Naked Science Forum

Non Life Sciences => Geology, Palaeontology & Archaeology => Topic started by: Azwan Faez on 06/02/2011 17:30:04

Title: Would the magnetic field change if geographic north is not magnetic north?
Post by: Azwan Faez on 06/02/2011 17:30:04
Azwan Faez  asked the Naked Scientists:
   
Would the magnetic field change in any way if magnetic north is not the same as the geographic north of the Earth?

What do you think?
Title: Would the magnetic field change if geographic north is not magnetic north?
Post by: CliffordK on 06/02/2011 23:30:37
Magnetic North has never been precisely aligned with true north, (the axis of rotation of the Earth).  Nor is the magnetic field direction completely uniform.  So all maps will show a correction factor for "magnetic North".

http://www.calvinistcadets.org/4d.php
(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fwww.calvinistcadets.org%2Fimages%2Fdeclinationmap.jpg&hash=db22b60972c04f63cb2f84fd7304977b)

I believe the theory is that the magnetic North has to do with actual differences in the rotation of earth's core with respect to the surface.  If such a rotation was to be perpendicular to the axis of Earth's rotation, then it would cause instability to the spin of the earth.

The moon/earth system maintains earth's axis of rotation to some extent with respect to the sun. 

The magnetic field gives some degree of protection to the earth from cosmic rays and solar winds.

(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fupload.wikimedia.org%2Fwikipedia%2Fcommons%2Fthumb%2Ff%2Ff3%2FMagnetosphere_rendition.jpg%2F360px-Magnetosphere_rendition.jpg&hash=08de67941e29c2541d82e1a8dee4cb1a)
(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fupload.wikimedia.org%2Fwikipedia%2Fcommons%2Fthumb%2F2%2F29%2FPlasmasphere.jpg%2F800px-Plasmasphere.jpg&hash=516dbddcb926bb00db42eb7a56b13a7e)

If the magnetosphere was tilted, it would likely open the earth to much higher solar radiation, likely on a seasonal basis.

Another question would be what would happen with a higher axial tilt.
Uranus is the only planet with a very high axial tilt...  giving it the effect of very wicked seasons.
http://en.wikipedia.org/wiki/Uranus#Axial_tilt

One other thing with a perpendicular magnetic field.
Interactions with the solar magnetic field would become more noticeable, with high seasonal variations.