system
Given the following post, respond as if you're commenting on Reddit:
human
Does light stop moving at absolute zero?

I know that absolute zero signifies that all matter stops moving. So, can a photon still travel through 0 K?
gpt
>absolute zero signifies that all matter stops moving  

This actually isn't the case. Quantum systems almost always have energy of motion which is still nonzero as you approach absolute zero temperature. For instance, electrons don't stop moving around their atoms because it's cold. What absolute zero does mean is that your system no longer has any excess internal energy it can lose.

>So, can a photon still travel through 0 K?  

The is more complicated. Temperature does not just exist on its own, it's a property—a substance has a temperature and different substances interact with light in different ways. So a medium at one temperature might impede light while a different medium at the same temperature lets it travel through just fine. Being close to absolute zero doesn't have anything to do with it.