What method is used by astronomers to infer the existence in space of a dark object of about 5 solar masses, such as a black hole?
A) infrared imaging of a region whose effective temperature is lower than the cosmic microwave background, rendering it dark
B) measurement of the gravitational redshift of spectral lines in the spectrum of the object
C) measurement of the effect of its gravitational force on a companion object in a binary system
D) estimation of the luminosity of the object and the application of the mass-luminosity relationship

Question

Quizplus · Accepted Answer

Astronomers infer the existence of a dark object, such as a black hole, by observing its gravitational effects on a companion object in a binary system. This method allows them to deduce the presence of the black hole due to its significant mass influencing the orbit of the visible companion star.

What Method Is Used by Astronomers to Infer the Existence