this post was submitted on 30 May 2025
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[–] [email protected] 24 points 2 days ago (1 children)

Yep. In fact there’s a process called inverse Compton scattering that essentially works this way. In ordinary Compton scattering, a photon scatters off a stationary electron and typically leaves with less energy (since the electron gets a kinetic kick). In inverse Compton scattering, a photon collides with a moving electron which can cause the photon to gain energy.

One application of this is to produce gamma-ray beams. You take a beam of light (often from a laser) and collide it head on with a beam of relativistic electrons traveling in the opposite direction. In the electron rest frame, the photon has gamma-ray energy, while in the lab frame it might only be visible light. The back-scattered photon can then be boosted to the gamma regime in the lab frame, and now you’ve got a gamma-ray beam.

[–] [email protected] 1 points 1 day ago

I just want know when my giant fission-powered robot can finally be armed with nuclear-pumped gamma lasers.

[–] [email protected] 10 points 2 days ago* (last edited 2 days ago) (1 children)

Yes (if you change the wording to “if I accelerate toward it until I’m moving near the speed of light relative to my original reference frame”).

[–] [email protected] 7 points 2 days ago (2 children)

So, while he accelerates toward it until near the speed of light in his original frame of reference, he will detect the oncoming photon as gamma radiation, but in my frame of reference where I'm not accelerating and just idling, and looking at the same photon, I'll still see the photon as not gamma radiation at all?

[–] [email protected] 7 points 2 days ago

I think if there's a guy accelerating to the speed of light and you're staring at a photon, you're missing out on some incredible things in this life.

[–] phdepressed 4 points 2 days ago

A blueshift or redshift depends on your frame of reference. Unless you are also moving you would see a redshift or blueshift.