Eli5 If you shine a laser up in the sky for ~3 seconds, does the beam eventually fizzle out or does it keep going until it hits an object?

Question

Eli5 If you shine a laser up in the sky for ~3 seconds, does the beam eventually fizzle out or does it keep going until it hits an object?

In: 5

Answer 1

It will be absorbed slightly be the air, but then travel through space and spread out more or less forever. Maybe some distant alien astronomer will be wondering why that star blipped slightly green, though probably not.