Behavior of compasses AFTER the magnetic pole

In summary: So, as long as you are in the magnetic field of the south pole, it will point towards the magnetic south pole. However, in the scenario described, the needle will rotate 180 degrees when passing over the south pole.
  • #1
jaumzaum
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So I know that a compass points to the south magnetic pole, that is near the north geographic pole. Let's consider the Earth to be a magnetized bar with all 4 poles aligned (for didactic purposes). The compass will try to "follow" the south magnetic pole, so, if I am in the Equator for example, it will point towards the geographic North. What if I pass the magnetic south pole (I am below the geographic north and above the magnetic south pole)? In my understanding the compass will continue to points towards the south magnetic pole, but in that case it will be pointing towards the opposite way, the geographic south!

Is this statement correct?
 
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  • #2
No. The way you set up your scenario means the needle will rotate 180 degrees when you step over the south pole.

Provided it's a very sensitive compass: the magnetic field there points skywards !

Wiki pic:

compare lower left needle with lower right

1589497693236.png
 
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  • #3
BvU said:
No. The way you set up your scenario means the needle will rotate 180 degrees when you step over the south pole.

Provided it's a very sensitive compass: the magnetic field there points skywards !

Wiki pic:

compare lower left needle with lower right

View attachment 262789

Thank you @BvU. Exactly in the magnetic south I am sure it will, but what about a little to the right of it, e.g. in the middle ground of the south-magnetic and north-geographic? I would say the field would have a much higher radial component, but the tangential component there will not be zero, and will make the compass point towards the geographic south, am I right?
 
  • #4
jaumzaum said:
e.g. in the middle ground of the south-magnetic and north-geographic
I thought that's not in your scenario

jaumzaum said:
magnetized bar with all 4 poles aligned
Did I misinterpret this ? 2 magnetic and 2 geographic is all I could think of.

jaumzaum said:
e.g. in the middle ground of the south-magnetic and north-geographic
...
the compass point towards the geographic south, am I right
Yes. The compass points to the magnetic pole. It does not know about the geographic pole.
 

1. What happens to a compass after the magnetic pole shifts?

After a magnetic pole shift, the behavior of a compass may change. The compass needle will align itself with the new magnetic field, which may result in the needle pointing in a different direction than before.

2. Can a compass still be used after a magnetic pole shift?

Yes, a compass can still be used after a magnetic pole shift. However, it may need to be recalibrated to account for the new magnetic field direction.

3. How often do magnetic pole shifts occur?

Magnetic pole shifts occur irregularly and can happen multiple times in a century or not at all for hundreds of years. The last major magnetic pole shift occurred about 780,000 years ago.

4. What causes a magnetic pole shift?

The cause of magnetic pole shifts is still not fully understood. It is believed to be the result of changes in the Earth's molten core, which generates the planet's magnetic field.

5. Are there any potential dangers associated with a magnetic pole shift?

There are no known direct dangers associated with a magnetic pole shift. However, changes in the magnetic field can affect navigation systems and communication equipment, which may have indirect consequences.

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