The average red giant in the night sky is about 1,000 times more luminous than the average main-sequence star.If both kinds of stars have about the same brightness,how much farther away are the red giants compared to the main-sequence stars?
A) 32 times farther
B) 1,000 times farther
C) 65 times farther
D) The red giants and main sequence stars have approximately the same distances.

Question

Quizplus · Accepted Answer

The luminosity of a star is proportional to the square of its distance if the brightness is the same. Therefore, the distance ratio is the square root of the luminosity ratio: √1000 ≈ 32.

The Average Red Giant in the Night Sky Is About