# What kind of physical force does the earth's magnetic field exert on any object?

Firstly let me waste a bit of your time by explaining I have not done much with maths or physics for ages! So please forgive my stupidity.

My question:
What kind of physical force does the earth's magnetic field exert on any object on earth?

My calculations (very probably deeply flawed):
Google says the earth's magnetic field is 0.3 - 0.7 Gauss in strength.
This is equal to 0.00003 - 0.00007 Tesla
T= 1(N/A*m)

I assumed:
N = newton
A = Area / surface in m2
m = mass of the (magnetic?) body(?) in kg

So the force on an object (weight: 1kg / contact area with ground: 1m2) would be:

T = N = 0.00003 - 0.00007 Newton

Now after someone has pounded my math into dust I still wonder if this only applies to a place on earth where the magnetic field lines are at a 90 degree angle with the earth's surface? And what would apply for a place around the equator for example?

vanesch
Staff Emeritus
Gold Member
Firstly let me waste a bit of your time by explaining I have not done much with maths or physics for ages! So please forgive my stupidity.

My question:
What kind of physical force does the earth's magnetic field exert on any object on earth?

My calculations (very probably deeply flawed):
Google says the earth's magnetic field is 0.3 - 0.7 Gauss in strength.
This is equal to 0.00003 - 0.00007 Tesla
T= 1(N/A*m)

I assumed:
N = newton
A = Area / surface in m2
m = mass of the (magnetic?) body(?) in kg

Nope, it is Newton per Ampere - meter. See http://en.wikipedia.org/wiki/Tesla_(unit [Broken])

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The Earth's magnetic field produces only torques on magnets like compass needles, because the compass needle is a magnetic dipole, equivalent to a magnetic monopole at each end. If we had any free monopoles around, they would be pulled to either the North pole (near Greenland) or the South pole (near Antartica).