Question

Why do young stars appear blue and old stars red?

• A. Because young stars are cooler than old stars.
• B. Because young stars are hotter than old stars.
• C. Because young stars are far away from the Earth.
  
• D. Because the light coming from young stars refract more compare to old stars.

Answer 1

The correct option is B Because young stars are hotter than old stars.

Young stars appear blue and old stars appear red because the young stars are hotter than the old stars. The hot stars emit more energy and appear blue, old star emits less energy and appear red.