What happens to light from a laser pointer if I shine it up into the sky at night?

Question

Provided it doesn’t hit a pilot in the eye!

In: 32

Answer 1

The photons fly off into space until they hit something. Most will probably hit dust or droplets in the atmosphere before reaching space, but some will probably leave the solar system.

Laser beams aren’t perfectly focused. They don’t spread out as wide as quickly as a flashlight beam, but they do spread a little over distance. That’s why it doesn’t look like the beam goes on forever. As it gets wider the beam gets less dense until its too spread out to see, but all those photons are still there, flying on until they hit something.