Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Megnatic Field Of Earth

  1. Mar 3, 2010 #1
    does earth has a megnatic field and if so how????????
     
  2. jcsd
  3. Mar 3, 2010 #2

    Pythagorean

    User Avatar
    Gold Member

    Yes. I don't think it's known for sure how, but a good guess is the motion of liquid-state metals in Earth's core, like iron.
     
  4. Mar 4, 2010 #3
    And there have been declines for unknown reasons in recent times...as well as shifts of north and south poles over the millenia...just wait until the man made global warming kooks find out that the magnetic field is about to undergo another upheaveal!!!

    another strange effect is that the north and south poles drift over time...deviation and variation are the two most importasnt variants in navigation

    http://en.wikipedia.org/wiki/Magnetic_variation#Variation
     
  5. Mar 9, 2010 #4
    but the megnatic field is caused by moving charges only how can movement of liquid state metal cause megnatic field?????????
     
  6. Mar 9, 2010 #5

    Pythagorean

    User Avatar
    Gold Member

    There are moving charges in it ;)
     
  7. Mar 10, 2010 #6
    all type of matter contains moving charges but on the whole every substance is neutral why is not magnetic field caused by other substances :confused:
    i m definatly missing something here:blushing:
     
  8. Mar 10, 2010 #7

    mgb_phys

    User Avatar
    Science Advisor
    Homework Helper

    Don't worry you're not as embarrassed as physics.
    The Earth's magnetic field is amazingly poorly understood even today, which is why we get away with handwaving explanations of the 'dynamo effect'.

    There are possible explanations from second order effects of a moving conductive (but overall uncharged) fluid moving in a field - a little like how the corriolis effect is a second-order effect of a rotating earth.
     
  9. Mar 10, 2010 #8
    If the earth is spinning doesn't that mean that the iron or whatever it is in the earth's core must be spinning. and when you spin isn't there acceleration? is it possible that in the earths core there is created some sort of strong electric field?
     
  10. Mar 10, 2010 #9
    electric field due to spin WOW that is some question
    my guess is that the earth spin with a CONSTANT anguler velocity (no accelaration ) if the earth were accelarating our days would be shortened with time!!
    but thats my personasl opinion could be wrong
     
  11. Mar 10, 2010 #10
    what are the efffects which are seen because of the megnatic field of earth ?????????
     
  12. Mar 10, 2010 #11

    mgb_phys

    User Avatar
    Science Advisor
    Homework Helper

    Important ones are:
    Compass needles point north.
    The effect of shielding us from solar radiation from the sun.
     
  13. Mar 10, 2010 #12
    even with CONSTANT angular velocity don't you get acceleration. towards the centre maybe? and then an electric field would be created magically causing a magnetic field to form perpendicular to a vector towards the centre of the earth, thereby pointing maybe to a north and south pole? . :smile: just speculating.
     
  14. Mar 10, 2010 #13
    maybe there are different materials inside the centre of the earth. and if the earth is spinning those materials are forced to the outside of the inner core. and then since those materials have different densities there could also be a distinct line that divides those two materials. even a third material between two materials. and if that third material has enough energy from heat could it accelerate electrons across a potential or something insane like that.
     
  15. Mar 12, 2010 #14
    actually when we talk about uniform circuler motion the average accelaration is zero we get only the instantaneous values of the accelaration !!!!(i guess)
    apart from that i m not completely familiar with the concept of electric field due to spin can you please enlighten me on that
     
  16. Mar 12, 2010 #15
    Well average acceleration is 0, but so is the average electric field. At any given moment there would be a changing electric field, which induces a magnetic field perpendicularly to that. I doubt I would provide you a fulfilling explanation. They do spin magnets in many devices though, try googling that.
     
  17. Mar 12, 2010 #16
    I think someone a long time ago buried a very large copper coil and batteries :biggrin:
     
  18. Mar 13, 2010 #17
    so the in that case megnatic field will also be zero (overall) but we will get some instantaneuos values right
    is that what you are trying too say ?
    but in that case the megnatic field it self would not be non uniform and an non uniform megnatic field will show non uniform effects which is not the case (if i m not wrong)
     
  19. Mar 16, 2010 #18
    the magnetic field isn't uniform to my knowledge. is it?
     
  20. Mar 16, 2010 #19
  21. Mar 16, 2010 #20
    when north goes south ??????????
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook