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If a photon is emitted from a light source moving at any speed, the photon will nonetheless always move at c (assuming it is emitted in a vacuum.)

If the speed of a photon's emitter cannot influence its speed, will the energy from its emitter's speed then contribute towards giving the photon a higher frequency? If not, where does this energy go?

I feel like I may be looking at incorrectly overall as I can't entirely justify why a photon would get anything from its emitter's speed (aside from an annihilating particle/antiparticle where they have to get rid of all their energy,) besides a weak analogy to emitting a photon being like throwing a ball.

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I don't think it's useful to consider this as energy from the emitter's speed. Photons don't have mass and so don't gain kinetic energy from the source's movement – Martin Beckett Jan 14 '12 at 5:51
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Yes. this is called the "Doppler Shift", and it happens because frequency of something emitting waves moving towards you is higher.

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I wasn't aware this applied to waves without a medium (although in retrospect it makes sense.) Thanks! – 0x5f3759df Jan 13 '12 at 16:46

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