Suppose you see two stars: a blue star and a red star. Which of the following can you conclude about the two stars? Assume that no Doppler shifts are involved. (Hint: Think about the laws of thermal radiation.)

Question

Quizplus · Accepted Answer

According to the laws of thermal radiation, hotter objects emit more radiation at shorter wavelengths (bluer colors) and cooler objects emit more radiation at longer wavelengths (redder colors). Therefore, if we see a blue star and a red star, we can conclude that the blue star is hotter than the red star. We cannot determine their distances or masses based solely on their colors.

Suppose You See Two Stars: a Blue Star and a Red