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

If it does not hit *anything*, yes.

It does not need a solid object, even a gas molecule could take out energy from a light wave.

That said, it actually takes no energy at all. It’s pretty easy. The conservation of energy says, that as long as you do not have any force counteract, there is not energy needed to continue whatever you are doing.