system
Given the following post, respond as if you're commenting on Reddit:
human
If a laser is shot in space and it doesn't hit it's target, what happens to the laser?

I'm thinking of like Battlestar Galactica and Star Wars, all space movies/tv shows in which they go to battle and shoot lasers at the enemies. Sometimes they miss. Does the laser keep going until it hits something? For how long?
gpt
Lasers have a certain amount of divergence, which will cause the spot size of the targeted laser to increase over distance/time, leading to reduction of the power density at whatever is hit. A rough estimate is that most laser tech humanity currently has / could build, would have a functional maximum range of our own solar system.

Edit: This applies even in a perfect vacuum, with no dust or other particles.