What is the mechanism for the energy output of quasars?

How many neutron stars are estimated to be in the Milky Way galaxy?   10         2000         30,000         100 million         100 billion

Suppose a quasar has a luminosity of 1012 LO. What is the smallest mass that the quasar could have and still continue to pull surrounding gas into itself?

Using a value for Hubble's constant of 71 km/s per Mpc, find the distance of a galaxy that is receding at a velocity of 1600 km/s.

Figure 2 shows the "rotation curve" of NGC 2742. It plots the “radial velocity (V)" (how fast material is moving either toward or away from us) that is measured for objects at different distances (R = radius") from the center of the galaxy. The center of the galaxy is at 0 kpc (kiloparsecs) with a speed of 9 km/sec away from us. (These velocities have been corrected for the observed tilt of the galaxy and represent true orbital velocities of the stars and gas.) 200 100 U4779 -100 As you can see, one side of the galaxy is moving with a negative velocity (spinning toward us), while the other side has a positive velocity (spinning away from us). Using Newton's gravity equation, we will be able to determine the gravitational mass of the entire galaxy and how the mass varies versus distance from the galaxy's center. -200 -8 8 -4 Radius (kpc) Read the following text carefully and follow the instructions: Select five radii spaced evenly from 0-10 kpc across the galaxy. Your selections should…

Astronomers estimate the mass of the stars in a certain galaxy to be about 3.0e40 kg, and the total mass of this galaxy to be about 1.2e41 kg. The amount of the galaxy’s mass is made up of dark matter is_____ percent.

What is messier 1 crab nebular

What are the similarities and differences between blazars and quasars?