| 1 |
The
quasar SDSS 1044-0125 has a redshift z=5.80. At what speed does this quasar
seem to be receding from us? Give your answer in km/s and as a fraction
of the speed of light c. |
| 2 |
Imagine driving
down a street toward a traffic light. How fast would you have to go so that
the red light (wavelength=700nm) would appear green (wavelength=500nm)? |
| 3 |
Suppose a
blazar at z=1.00 goes through a fluctuation in brightness that lasts one
week (168 hours) as seen from Earth.
(a) At what speed does the blazar seem to be moving away from us?
(b) What is the maximum size (in AU) of the region from which this blazar
emits energy? |
| 4 |
Suppose the
distance from point A to point B in 
is 26 light-years and the blob moves at 13/15 of the speed of
light. As the blob moves from A to B, it moves 24 light-years toward the
Earth and 10 light-years in a transverse direction.
(a) How long does it take the blob to travel from A to B?
(b) If the light from the blob at A reached Earth in 2000, in what year
does the light from B reach Earth?
(c) As seen from Earth, at what speed does the blob appear to move across
the sky? |
| 5 |
Observations
of a certain galaxy show that stars at a distance of 16 pc from the center
of the galaxy orbit the center at a speed of 200km/s. Use Newton's form
of Kepler's third law to determine the mass of the central black hole. |
| 6 |
Calculate
the Schwarzschild radius of a 109-solar-mass black hole. How
does your answer compare with the size of our solar system?
|