Eli5: If a laser is shined into space will it continue to infinity (if it doesn’t hit a solid object)?

Question

Seems like a gargantuan, if not infinite amount of energy would be required for this to occur

In: 10

Answer 1

It won’t. Outer space isn’t a perfect vacuum. Some of the photons of light will hit stray bits of matter and scatter and be absorbed. Eventually, it won’t be much of a beam anymore. Light has a finite velocity so it cannot literally travel to infinity without an infinite amount of time.