• Question: Why can't a charged particle accelerate to the speed of light?

    Asked by dyaskelly to Sam, Ben, Clare, Ezzy, Mario on 16 Mar 2012.
    • Photo: Clare Burrage

      Clare Burrage answered on 15 Mar 2012:

      It’s not the charge that stops the particle from traveling at the speed of light, but its mass. You can’t accelerate massive particles to the speed of light, because that would need an infinite amount of energy.
      All of the charged particles that we know of do have a mass, but I think that’s just a coincidence.

    • Photo: Mario Campanelli

      Mario Campanelli answered on 15 Mar 2012:

      actually, right now we only know two particles which are massless, and both are neutral bosons (that means, marrying forces): the photon (light) and the gluon, responsible for carrying the strong nuclear force. But the gluons do not travel very far, since the laws of quantum mechanics prevent them from doing so; so the only particle actually going to the speed of light is… light!

    • Photo: Elizabeth Pearson

      Elizabeth Pearson answered on 16 Mar 2012:

      It’s mass not charge that stops something from accelerating to the speed of light. The closer to the speed of light something gets the more massive it gets as the energy is converted to mass. Currently we don’t now anything that doesn’t have mass but does have charge.

    • Photo: Ben Smart

      Ben Smart answered on 16 Mar 2012:

      Any particle that has mass can’t be accelerated to the speed of light. The faster you make the particle go, the harder is is to make it go any faster. You keep having to use more and more energy to make it go any faster, and you’d end up needing an infinite amount of energy to make it travel at the speed of light.

      Any particle that doesn’t have mass already travels at the speed of light though.

      As for accelerating charge particles, when you accelerate charged particles they emit radiation, and so lose energy, making it even harder to accelerate them further. Eventually they’ll be going so fast that all the energy you’re putting in to accelerate them will be emitted as radiation by the particles.

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