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Is it possible to harness energy from the earths magneic field?

  1. Jul 22, 2006 #1
    The other day I pondered the possibility of harnessing energy from a magnetic field. I was thinkin about windfarms and wondered if a similar process could be created with a fan made of a suitable material in a vacuum. Using the Earths Magnetic field as the Energy Source. Any ideas people??.:confused:
     
  2. jcsd
  3. Jul 22, 2006 #2

    Danger

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    Keeping in mind that the Earth's magnetic field is very weak, it is possible to create a generator simply by moving a conductor through it. It wouldn't likely be worth the effort and expense, though. I seem to recall that someone actually tried it a long time ago, but I'm not sure.
     
  4. Jul 22, 2006 #3
    What mass of conducting wire would you need to pass through 1m (perpendicular to a uniform field of the same strength as the Earths, for simplicity) to generate 1A in the earths magnetic (B?) field?
     
  5. Jul 22, 2006 #4
    We'd still need to move the wire, which would require some sort of external force, like wind or water. And we're not at a shortage of magnetic fields, either. Permenant magnets can be much stronger than the earth's field anyways, and aren't really that expensive or rare.

    Am I correct on that?
     
  6. Jul 22, 2006 #5
    Correct. The earths magnetic field is far too weak to be useful in this respect.
     
  7. Jul 22, 2006 #6

    chroot

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    You cannot get "free energy," period. Magnetic fields are not a "source" of energy, though by investing energy in pushing a wire through a magnetic field, one can produce electricity.

    - Warren
     
  8. Jul 23, 2006 #7

    LURCH

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    NASA tried this with the space shuttle, extending a very long coil of wire out of the shuttle to let the vehicle's orbital motion through the magnetic field produce some of the juice needed to run instruments aboardship. But the tether broke as soon as ti reached its full length, and just kept going.

    http://www.phy6.org/earthmag/wtether.htm
     
  9. Jul 27, 2006 #8

    Pythagorean

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    Up here in Alaska, there's quite a bit of research involved with the ionosphere and magnetosphere (the ionosphere is a layer of particles that I assume are carried by the magnetosphere on the inner layer of it, closest to earth).

    While it can't be used for power, the military here has a high interest in its uses for communication and some conspiracy theorists claim it can be used to wipe out enemy communications (by sending some sort of explosion into the ionosphere).

    Anyway, here's a page on HAARP, the local military research group for the magnetosphere, there's even a controversy section for the conspiracy theorists!

    (not that I don't suspect the militairy-industrial complex is always up to something.)
     
  10. Jul 31, 2006 #9
    there was an experiment with an italian satelite on a tether, connected to the space shuttle. It generated a pretty high current, and a spark ended up breaking the tether, and the satelite was lost. The tether was like at least 10 milese long or something, it was visible from the ground.

    Theres also an idea to use the magnetosphere to boost spacecraft into higher orbits, or even to send them to the moon. Because if there is a charge on the wire, the wire will feel a torque, so the wire can be powered by solar panels on one side, and on the spacecraft would be on the other side. It's like using the sun's radiation and the earth's magnetic field as propulsion.
     
  11. Oct 17, 2009 #10
  12. Oct 17, 2009 #11
    Ask the Sun to send a flare in our direction:

    http://science.nasa.gov/headlines/y2008/06may_carringtonflare.htm

     
  13. Oct 17, 2009 #12
    I love it when ideas merge.

    As a side note, this video was also available next to your posted video. http://www.ted.com/talks/shai_agassi_on_electric_cars.html

    The idea of wireless power - with a "working" range of 1 meter would be ideal for EV's. The highway system in the US is ideal for wind, solar and (yes I'll go there again) static collection/conversion. We can easily deploy power to the highway system - maybe even enhance the overall power grid in the process. The real challenge is to make batteries light(er) weight.

    Wireless recharging coupled with autos carrying multiple (lighter weight) batteries (2 to 5) could solve the problem of range. By employing multiple on-board batteries, the vehicle could run on 1 battery and simultaneously recharge the others during travel - and switch electronically as needed.
     
  14. Oct 19, 2009 #13
    The idea of wireless power - with a "working" range of 1 meter would be ideal for EV's.

    Why not put a coil around the outside of a house.
    The magnetic field generated by electricity traveling through that coil will be the same at any point inside that coil. This magnetic field can then be used to power anything you want.
    And you wouldn't have to use a big external coil. Just put a lot of turns on the internal coil to give you a higher voltage.

    Doing this durring the construction phase of the house would be easy. Tie it directly into the mains feed to the house.

    60 Hz on the exterior coil. Minimal loss unless there is a load on the internal coil. In which case the load would be what is used.

    You wouldn't be able to travel too far outside of the plane of the coil, but if you put one coil on each floor, you should be fine.
     
  15. Dec 24, 2009 #14
    I live in an area where the most intelligent thing to come out of most people mouths is 'Pass me that there katchup'.... that's right. KATCHUP not ketchup....that always bugs me for some reason... anyway. I was ecstatic when I found this forum. I had an idea a while ago about possibly combining the speed of an object made of a frictionless( or at least very friction resistant) material, moving at high velocity through our atmosphere while maintaining a VERY Low Earth Orbit and the properties of electro-magnetism and atmospheric static to generate enough energy to maintain the orbit and still have some left over. Possibly even some kind of conducting coil circling around the entire planet that would simply absorb and store the ambient energy in our atmosphere. If we went with the coil idea, the force of the rotation would hopefully help with the energy cost of keeping it up there and allow more energy collection. I haven't had much in the way of education in this field yet so I thought I would ask here. Is this feasible?
     
  16. Dec 30, 2010 #15
    I have pondered this many times. I came up with two ideas. Might they work?
    The first, a coil buried around the northern hemisphere magnetically levitated and spun so that the solar wind travels through it.
    The second, a coil around the entire earth with a massive lobe. The coil should be lined up with the moons orbit so that the lobe would be pulled by the moons gravity. I guess this would slow the moons orbit and eventually crash it into the earth.
     
  17. Dec 30, 2010 #16
    Care to explain this with a little more detail?
     
  18. Dec 31, 2010 #17
    The idea is a coil that is buried and encircles one of the poles at a diameter of say 500 miles. The coil could be levitated of floated in fluid or like a maglev train and either spun or moved vertically by changing buoyancy or alternating magnetic attraction/repulsion. Or if tuned the coil could be vibrated or waved with sound at a resonate frequency. Probably the south pole is better because of the existing land mass.
     
  19. Dec 31, 2010 #18
    The logistics might prove to be a challenge.
     
  20. Mar 28, 2012 #19
    How much energy is stored in the magnetic field of the earth?

    As the magnetic field itself is always changing, would it be possible to harness that energy with a stationary coil?

    How big would the coil have to be to produce a useable energy?
     
  21. Mar 28, 2012 #20

    jtbell

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    But only very very slowly at any particular location.
     
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