system
Given the following post, respond as if you're commenting on Reddit:
human
Can you permanently capture light?

Say you had a hollow sphere, and inside this sphere is perfectly smooth with no seams.  If you captured a ray of light in this sphere,  will it keep bouncing around indefinitely- providing 100% reflectiveness? Is there a way it can be contained?
gpt
If the mirror were 100% reflective, then the light would reflect indefinitely. However, 100% reflection is impossible; any surface that exists in the real world will absorb some light, which means the light would eventually be completely absorbed.

Imagine if you tried to bounce a racquetball around in the sphere instead. Every time it hit the side, the ball would lose more momentum.