system
Given the following post, respond as if you're commenting on Reddit:
human
Does gravity effect wavelengths or energy? such as radio, light and so on.

Could something like a blackhole effect the wavelengths and energy of radio signals, light and turn them into different parts of the electromagnetic spectrum?
gpt
In fact, this partially explains why black holes are black. As you know, the speed of light is invariant. So if you shoot a beam of light away from the singularity, what happens? With massive particles, you would say that no matter how fast they go, if they're within the event horizon, they will slow to a stop and then fall back instead of escaping.

But what about light? Light cannot slow down. So how can the gravity prevent light from escaping? Well, photons don't get slower, but they do lose energy. The equation works out the same: no matter how energetic, if a photon is emitted within the event horizon, it would need to lose all of its energy (i.e. have an infinite wavelength) before escaping. So we see no energy escape, thus no photon.