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B Shapes and gravitational radiation

  1. Oct 3, 2016 #1

    wolram

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    IIRC , a perfect sphere will not be detectable with a gravitational detector, but an ovoid shaped body will, why is this so? or am i wrong.
     
  2. jcsd
  3. Oct 3, 2016 #2

    phinds

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    Why do you think what you think?
     
  4. Oct 3, 2016 #3

    wolram

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    I found this on wiki
    Vhttps://en.wikipedia.org/wiki/Gravitational_wave#Rotating_neutron_stars

    As noted above, a mass distribution will emit gravitational radiation only when there is spherically asymmetric motion among the masses. A spinning neutron star will generally emit no gravitational radiation because neutron stars are highly dense objects with a strong gravitational field that keeps them almost perfectly spherical. In some cases, however, there might be slight deformities on the surface called "mountains", which are bumps extending no more than 10 centimeters (4 inches) above the surface,[45] that make the spinning spherically asymmetric. This gives the star a quadrupole moment that changes with time, and it will emit gravitational waves until the deformities are smoothed out.
     
  5. Oct 3, 2016 #4

    phinds

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    So it seems you have answered your own question.
     
  6. Oct 3, 2016 #5

    wolram

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    No, I do not understand the mechanism for the production of gravitational radiation.
     
    Last edited by a moderator: Oct 3, 2016
  7. Oct 3, 2016 #6

    Chalnoth

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    In order to have gravitational radiation, you have to have a changing quadrupole moment of the field. A simple spinning sphere won't have that.
     
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