How would astronomers,ancient or modern,use a "standard candle"?
A) They would use its faint light to illuminate the setting dials of their telescopes.
B) They would use it to measure time,using its slow but steady melting.
C) They would use it to generate a known and extremely reproducible standard spectrum for comparison with stellar spectra.
D) They would measure distance by comparing its apparent brightness with its known absolute brightness.

Question

Quizplus · Accepted Answer

Astronomers, both ancient and modern, use a "standard candle" to measure distances. A standard candle is a celestial object with a known intrinsic brightness or luminosity. By comparing the observed brightness of the standard candle with its known absolute brightness, astronomers can determine the distance to the object. This is known as the distance modulus method and is used to measure the distances of galaxies and other celestial objects.

How Would Astronomers,ancient or Modern,use a "Standard Candle