The stars Procyon and Betelgeuse both appear equally bright to Earthbound viewers.Yet Betelgeuse emits 5000 times more light than Procyon.Why do they appear to be equally bright?

Question

Quizplus · Accepted Answer

The apparent brightness of a star is affected by both its actual luminosity and its distance from Earth. Betelgeuse may emit 5000 times more light than Procyon, but it is also much farther away from Earth, so the two stars appear equally bright. This is similar to how a distant streetlight might appear equally bright as a closer car headlight, even though the car headlight emits much less light than the streetlight.

The Stars Procyon and Betelgeuse Both Appear Equally Bright to Earthbound