A.) Suppose you want to construct a scale model of the Milky Way and Andromeda galaxies using two frisbees. How far apart should you place the two frisbees? Would they both fit in the classroom? How about a large lecture hall? A stadium?
B.) The light we receive from the Andromeda galaxy left it approximately 2.4 million years ago. Assuming that Andromeda is moving directly toward the Milky Way, and using the information given by Croswell in Ch. 1, estimate how much closer the Milky Way is to us *now* than it was when that light left. What fraction of the total distance is this? In the scale model above, how much closer would the two frisbees now be?
Suppose you observe the H α line (rest wavelength = 656.3 nm) from an edge-on spiral galaxy. You find that at the center of the galaxy the line is at 656.5 nm. At a distance 50,000 ly from the center, the H α line is at 656.0 nm and 657.0 nm on the left and right sides, respectively.
A.) Is the galaxy moving toward or away from the Milky Way? How fast?
B.) How fast is the galaxy rotating?
How far from the Sun is this binary star system?
Assuming the two stars are at exactly the same distance from the Sun,
compute the physical separation between Albireo A and B in AU.
P^{2} = a^{3}/(M_{1}+M_{2})
Prove these expressions are equivalent by looking up the values of G, the AU and the Solar Mass given in your textbook, (all in MKS units), to show that:
4π^{2}/G = 1 yr^{2} M_{SUN} /AU^{3}