system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What colours are beyond infrared and ultraviolet?

What colours could potentially exist when you keep going further along the colour spectrum? I imagine there could possibly be an infinite amount of colours, like there could be an infinite amount of radio frequencies.
gpt
Colour only makes sense as a quality which our brains interpret.  One cannot *imagine* a new colour, although some people and animals might be able to perceive more colours owing to things such as having more colour light receptors or other physical adaptions.  

In terms of the electromagnetic spectrum, the limits are essentially infinite.  You could make arguments for the longest wavelength radio wave having a wavelength on the order of the Observable Universe and highest energy gamma ray having a wavelength just small enough such that the energy concentration does not spontaneously form a black hole.