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Energy and Gravity

  1. Jul 18, 2008 #1
    Gravity is the mutual attraction between matter right?
    I heard photons are light particles, so would that mean theres an attraction between photons and photons or photons and regular particles. Since matter is a concentrated form of energy and light is energy wouldn't that mean there would be a mutual attraction between energy(in this case light). Would there also be a attraction between energy and matter.

    BTW I'm just some curious 14 year old so don't laugh at me :(
    Forgive me for making a lot of typos.
  2. jcsd
  3. Jul 19, 2008 #2


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    Gold Member

    Yes gravity is the attraction between matter. In Newton's equatyion for gravitational attraction you need mass to create a force. Photons how ever have no mass so no force goes between them. Now to avoid confusion I'll explain about E = mc^2, this confused me alot. E= mc^2 is only for rest mass, photons rest mass is 0, since they are always moving we can't use this equation.
  4. Jul 19, 2008 #3
    Here's some info I found... not sure if it helps your understanding.


    "For most average objects, momentum is truly mass x velocity. When motion
    figure anything out until you reach speeds of perhaps thirty million meters
    you reach speeds close to the speed of light.

    magnetic force pushes sideways, perpendicular to the field direction.
    Gravitational force is just gravitational field multiplied by the mass being

    electric and magnetic fields."

    Dr. Ken Mellendorf
    Illinois Central College


    Source: http://www.newton.dep.anl.gov/askasci/phy00/phy00332.htm

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