# Do massless particles create tiny gravity-booms?

So just a precursor, my main focus is math and I don't fully understand everything in physics so I apologize if this has an obvious answer or the wrong tags are used.

That being said, I do know that mass-less particles travel at the speed of light and they have energy, meaning they exert a gravitational force. I also know that gravity travels at the speed of light. By knowing these 2 things can we conclude that light makes a sort of sonic boom with gravity being the pressure wave and the mass-less particle being the supersonic object?

• Note that for light, one doesn't get Cherenkov radiation (roughly the equivalent of a Mach cone for sound) until the emitter's speed exceeds the local speed of light. So you'd have to either have a warp bubble or a matter distribution with a gravitational index of refraction. – rob May 4 '18 at 0:46
• @rob, I'm saying that photons exert gravitational waves in the direction they're traveling and since the wave will travel at the speed of the photon it will be like a sonic boom but for gravity. – Jacob Claassen May 4 '18 at 0:59
• For a massless photon traveling through vacuum, it can't create a "gravity boom" because the energy would have to come from somewhere, and we know from astronomy that photons don't lose energy traveling through vacuum. – Peter Shor May 4 '18 at 2:18
• If you consider electromagnetism, no electromagnetic waves are produced for a moving charged object that is not accelerating. Using that as an analogy I would imagine a light pulse would carry some miniscule gravitational field but wouldn't lose energy due to radiation. Maybe someone has done the calculation for classical GR coupled to classical EM. – octonion May 4 '18 at 2:21
• @PeterShor, would creating this gravity boom lower the energy of the photon? Because it interacts with gravity regardless. This would just be the gravitational effect clumping together. If that makes sense... – Jacob Claassen May 4 '18 at 2:29