Astronomers believe that the massive object at the center of the Milky Way is a black hole because
A) images show an accretion disk surrounding an empty spot.
B) gravitational wave measurements indicate a black hole is there.
C) observations at X-ray waves, infrared waves, and radio waves limit the size of the object to smaller than 10 AU.
D) it is necessary to explain the Galaxy's rotation curve.

Question

Quizplus · Accepted Answer

Observations at various wavelengths, including X-ray, infrared, and radio, have shown that the object at the center of the Milky Way is extremely compact, with a size smaller than 10 AU, which is consistent with the characteristics of a black hole.

Astronomers Believe That the Massive Object at the Center of the Milky