system
Given the following post, respond as if you're commenting on Reddit:
human
If light has no mass, when it moves, is it doing work?

If light has no mass, when it moves, or when something moves it, is it doing work?  If not, what is it doing?  Is any work accomplished to move light particles?
gpt
*Nothing* does work simply by moving; "work" in physics means a force applied over some distance parallel to that force. It's impossible to apply a force to light in parallel directions (since you can't change its velocity), so it's impossible to do work to light.