Assume that an average globular cluster is 25 pc in diameter. If you observe a galaxy that contains globular clusters that are 9 arc seconds in diameter, how far away is the galaxy? (Hint: Use the small-angle formula)

If a standard passenger aircraft can fly at 0.37 km/s (828 mph), how long (in yr) would it take to reach the Sun? How long (in yr) would it take to reach the galactic center? (Note: 1 pc = 3.1 ✕ 1013 km. The radius of the Sun's orbit around the galactic center is approximately 8,300 pc.)

If a standard passenger aircraft can fly at 0.26 km/s (582 mph), how long (in yr) would it take to reach the Sun? yr How long (in yr) would it take to reach the galactic center? (Note: 1 pc = 3.1 ✕ 1013 km. The radius of the Sun's orbit around the galactic center is approximately 8,300 pc.) yr

If a galaxy has an apparent radial velocity of 2000 km/s and the Hubble constant is 70 km/s/Mpc, how far away is the galaxy?

Suppose you observe a star orbiting the galactic center at a speed of 1500 km/skm/s in a circular orbit with a radius of 24 light-days. Calculate the mass of the object that the star is orbiting.

What evidence can you cite that our galaxy has a galactic corona?

If a quasar is 1,640 times more luminous than an entire galaxy, what is the absolute magnitude of such a quasar? (Note: The absolute magnitude of the Milky Wag Galaxy is about -21. Use the formula for magnitude and flux ratio, Mv - Ma = 2.5log(Fa\Fb)).

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…

The Sun is at a distance of about 8 kpc from the galactic center and moves around the galactic center in a circular path with a velocity of about 220 km s. Make a rough estimate of the mass of the Galaxy.

If a quasar is 2,000 times more luminous than an entire galaxy, what is the absolute magnitude of such a quasar?  Note: The absolute magnitude of the Milky Way Galaxy is about −21. Hint: Use the formula for magnitudes and flux ratios,