When we say that a cluster of galaxies is acting as a gravitational lens, what do we mean?
A) It magnifies the effects of gravity that we see in the cluster.
B) It is an unusually large cluster that has a lot of gravity.
C) It bends or distorts the light coming from galaxies located behind it.
D) The overall shape of the cluster is that of a lens.
Question 2
What kind of object do we think lies in the center of the Milky Way Galaxy?
A) a 3- to 4-million-solar-mass black hole
B) a gigantic X-ray binary system
C) a dense cluster of young, hot stars
D) an enormous collection of dark matter, which explains why we detect no light at all from the galactic center