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my question in regards to light. Since gravity warps space time, and we have discovered gravitational waves. Would the light at the front of the wave, be traveling faster than lightspeed? Essentially like a surf board on a wave?

Also, does gravity behave differently at light-speed? Would faster than light-speeds nullify gravity?

Qmechanic
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Curtis Rusin
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    The key question is: how are you measuring the speed of light? Remember that warping spacetime would also warp your ruler and stopwatch as well. – probably_someone May 04 '20 at 23:11
  • @probably_someone But according to your ruler and stopwatch, they would measure $c$ to be the same. They would only appear warped compared to some other reference frame.

    Also, under what intuition would light be travelling faster at the front of the grav wave? And doesn't a surfboard ride the crest of the wave? Rather than being 'in-front' of it?

     – SamuraiMelon May 05 '20 at 00:57
  • @SamuraiMelon "They would only appear warped compared to some other reference frame" - That's the point. "Also, under what intuition would light be travelling faster at the front of the grav wave?" I never made that claim. "And doesn't a surfboard ride the crest of the wave? Rather than being 'in-front' of it?" Why would the dynamics of a surfboard be at all relevant here? Do you have evidence that gravitational waves behave in any way similar to water waves? If not, this is not a particularly apt analogy. – probably_someone May 05 '20 at 01:31
  • @probably_someone, Sorry my comment was probably rather misleading, only the 1st thing was addressed to you. In regards to both our points stating the same thing, regardless of reference frame, all the grav waves would travel at $c$.

    Knowing that Curtis would be notified, the rest of the comments were addressed to him, quoting things directly from his question.

     – SamuraiMelon May 05 '20 at 12:51

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Gravitational waves always move at the speed of light as you say. Light also moves at the speed of light. For the question does light move faster than the speed of light in a gravitational wave. Well the answer is no. This is because light can never move faster than the speed of light. This is because the maximum speed through spacetime is the speed of light,c. Normal object move through time at the speed of light. Sometimes this can be a combination of moving through space and time. However normal matter could never reach the speed of light through space. Light however can move at the speed of light but since it is moving at this speed it experiences no time. Since light will not move any faster it will lose or gain energy to the gravitational wave. The gravitational wave will not speed up either due to the fact that it too is moving at the fastest speed possible-the speed of light.

MiltonTheMeme
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  • I find an inherent error in this but it is simply because it relates to the 5th law of thermodynamics. I'm not saying you are wrong in what you've said because it is correct according to current understanding. It just occurs to me that light does travel at different speeds and is never exactly the same velocity universally but, the mathematics used to measure it is flawed by being integral rather than independent of the universe. I think this is the point OP is making but not having the descriptor tools available since they don't yet exist. – Rhodie May 31 '20 at 07:38
  • Light can move at different speeds through different materials. The light itself is not moving slower. It is the interaction between the materials that slows light down. – MiltonTheMeme May 31 '20 at 13:51
  • For example it can happen in air or any medium. However in the vacuum of space light always moves at the speed of light, c. – MiltonTheMeme May 31 '20 at 13:52
  • But that's just the point the op was making, it's in space and light is not at a constant velocity. Even Einstein said everything is relative... – Rhodie May 31 '20 at 14:36
  • If you look closely at the special theory and general theory of relativity, everything is relative except for the speed of light. Here it is:https://physics.stackexchange.com/questions/2230/why-and-how-is-the-speed-of-light-in-vacuum-constant-i-e-independent-of-refer – MiltonTheMeme May 31 '20 at 14:38