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

The photon doesn’t require energy to move, it requires energy (or mass] to STOP (or slow down, or be absorbed)

Imagine throwing a rock in empty space, it will go until it hits something with only the energy from your arm

The photon has no mass but it still follows the same principle