Magnetic Fields Around Earth: Effects on Smaller Magnetic Fields

In summary, the Earth's magnetic field is actually very weak, and constant magnetic fields do not interfere with electromagnetic wave propagation. The combined effect of the Earth's magnetic field and other magnets already interferes with medical equipment, radio wave propagation, and other devices that create a magnetic field. The Earth's magnetic field has a huge dipole moment, but its resulting field is smaller than that of a common fridge magnet. However, charged particles traveling through the field can have a significant impact. While the Earth's magnetic field can disrupt some experiments, it can easily be cancelled out by using a small coil and adjusting the current.
  • #1
TWC59
2
0
Since we have such a strong magnetic field around the earth, why does it not interfere with smaller magnetic fields we use such as medical equipment, radio wave progagation and other things that creates an magnetic field ?
 
Physics news on Phys.org
  • #2
Earth's magnetic field is actually very weak. Also, constant* magnetic field does not interfere with electromagnetic wave propagation in any way.

* In fact, electromagnetism is linear, so an EM wave propagates regardless of what other magnetic and electric fields are present, at least through vacuum, but an oscillating magnetic field would create noise that could potentially cause problems for the receivers.
 
  • #3
Hello, its a most common problem regarding the interference of the Earth's magnetic field with the other magnet within( or on) the Earth's surface. The magnetic effect shown by all the magnets on the Earth is the combined (or the already effected) effect of the Earth's and the magnet. For instance, the north pole of a magnet points towards the magnetic south pole of the earth. Had there been no magnetic field of the earth; the orientation of the taken magnet would have been opposite! Hence, magnetic fields we use such as medical equipment, radio wave propagation and other things that creates an magnetic field are ALREADY interfered by the Earth's magnetic field!
 
  • #4
Thank you! This is what I thought but just was not sure. I expermint wih RF and antenna design. I know we have an electrostatic and electromagnatic with radio progragation, and one creates the other. I am the back yard mechanic type, so I have a lot of questions about our magantic field in regarding RF. I guess a good example would be the aroura and 50mhz reflection. This indeed affect RF at this frequency but I did not know about all the rest. Thank you for your input.
 
  • #5
You probably know about magnetic dipoles then.

Earth has a huge dipole moment which is approximately centered at the center of the planet. So on the surface you are looking at the magnetic field of a dipole some 6360 km away. The resulting field is quite small, even smaller than that of a common fridge magnet. But fridge magnet has a very small dipole moment, so that when you get a little distance away its field will have dropped to below the Earth's field.

Charged particles from the sun or elsewhere have to travel thousands of km through this field, so the integrated effect is pretty large.

There are some experiments such as electron spectroscopy that are disturbed by the Earth's magnetic field. But as the field is static, it is easy to put a small coil around the experiment and tune the current until the Earth's field is cancelled.
 

FAQ: Magnetic Fields Around Earth: Effects on Smaller Magnetic Fields

What is a magnetic field?

A magnetic field is a region of space where a magnetic force can be detected. It is produced by moving electric charges and can be represented by magnetic field lines.

How does Earth's magnetic field affect smaller magnetic fields?

Earth's magnetic field has a significant influence on smaller magnetic fields, as it creates a protective shield around our planet that deflects harmful solar wind particles. This can alter the direction and strength of smaller magnetic fields within the Earth's atmosphere.

What are some examples of smaller magnetic fields affected by Earth's magnetic field?

Some examples of smaller magnetic fields affected by Earth's magnetic field include the magnetic fields of compass needles, animal migration patterns, and the aurora borealis (or Northern Lights).

Can Earth's magnetic field change over time?

Yes, Earth's magnetic field is constantly changing and can even reverse its polarity. Scientists believe that these changes are due to the movement of molten iron in the Earth's outer core.

How does Earth's magnetic field protect us from harmful radiation?

Earth's magnetic field creates a barrier around our planet that deflects charged particles from the sun (known as solar wind) away from Earth's atmosphere. This protects us from the harmful effects of these particles, such as damage to satellites and disruption of electronic systems.

Similar threads

Replies
7
Views
2K
Replies
14
Views
722
Replies
2
Views
704
Replies
8
Views
1K
Replies
3
Views
2K
Back
Top