The visible parts of galaxies contribute about one-tenth of the critical density of the universe.
Indicate whether the statement is true or false
Question 2
In M82, observations indicate that there are several bright sources close to the center of the galaxy. These might be
A) supernovae.
B) accretion disks of supermassive black holes, millions of times as massive as our sun.
C) accretion disks of intermediate black holes, hundreds of times as massive as our sun.
D) accretion disks of stellar mass black holes.
E) red giants in the process of forming planetary nebulae.
