Astronomers Now Think That There Is a Black Hole with More

Multiple Choice

Astronomers now think that there is a black hole with more than 4 million times the mass of our Sun at the center of our Galaxy? Roughly how large would the event horizon of such a supermassive black hole be?

A) the size of our Moon
B) about 4 light years across
C) about 17 times the size of the Sun
D) about the size of an atom (so much mass really compresses the event horizon)
E) we can't answer this question without knowing exactly what kind of stars were swallowed by the black hole