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The speed of light (mander.xyz)
submitted 5 months ago by to c/science_memes@mander.xyz
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[+] -6 points 5 months ago (4 children)

They have mass. Everything that has energy has mass. They don't have inertial mass but it's just part of the equation

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  • [–] 4 points 5 months ago

    I think you are stating that backwards.

    You can definitely say that everything with mass has energy. And yeah the two are kind of interchangeable.

    But that does not mean that a photon HAS mass. It just means that we can calculate how much mass its energy is equivalent to.

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  • [–] 3 points 5 months ago (2 children)

    They have momentum, not mass, in relativistic physics you need something more complex than p=mv to describe momentum.

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  • [–] -4 points 5 months ago (1 child)

    Energy=mass always. Theoretically you can make a black hole out of light, or you can turn that photon energy into inertial mass by running light in a closed loop.

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