Eli5 why are you able to see lights far away but the light it projects doesn’t go nearly as far? (Car lights, street lights, etc)

Question

Eli5 why are you able to see lights far away but the light it projects doesn’t go nearly as far? (Car lights, street lights, etc)

In: 0

Answer 1

There is an inverse square Law describing the drop off in light intensity. Basically each time the distance doubles the light intensify is just a quarter.