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Gravitational lensing

  1. Jan 28, 2014 #1
    I recently engaged in a argument with a fellow that tried telling me that gravitational lensing was not because of the warping of space due to mass but instead he told me this

    " On a cosmic scale , the mowing energy is in the form of angular momentum, quantum mechanically , the creation of rotation-counter rotation is easy to see and understand. The light bending or space bending theories cannot get things spinning and happily ignore 99% of the entire cosmic moving energy. in the case of the existing counter rotating galaxies the nonlocal quantum mechanical momentum creation explains it just fine"

    Now am I just being ignorant or does this statement make no sense what so ever when it comes to gravitational lensing?

    "He said that a prism bends light and in such case the photons interact directly with the medium that is the glass that's space bending isn't it"

    Someone please tell me what he is trying to say lol

    I tried every argument and source I could use to try and show him that light needs a media to travel through and in space there are no glasses so what is the light propagating through to bend it??
  2. jcsd
  3. Jan 28, 2014 #2
    any strong gravitational source can form a lens by bending light stars, galaxies, dark matter etc.
    space is never truly empty at any point it is filled with radiation, quantum particles etc so light does travel through a medium though far less dense than a prism. A high enough energy-mass in a given region can form a lens however densities high enough in those region are typically near another stellar mass ie dark matter, stars etc.


    light paths in our universe can also be affected by the universes geometry however this would not be strong enough nor have the correct properties to form a lens. see some of the images on the wiki article to see why that is so.

    see this article on the light bending due to geometry

  4. Jan 28, 2014 #3


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    mordred has given you links that will allow you to explore gravitational lensing and how it actually work. The statement above by your friend is incoherent rubbish.
  5. Jan 28, 2014 #4
    Thank you guys!! I knew a lot about gravitational lensing but I could not for the life of me figure out these little details when debating lol The whole debate just had me second guessing myself but now thanks to you guys its obvious he has no idea really. He also kept bringing up quantum non locality but from what I have learned is that non locality does not allow for faster than light communication. is this right??
  6. Jan 28, 2014 #5
    correct, entangled particles and quantum tunneling will not allow faster than light communications
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