AST 248: The Search for Life in the Universe

1. The speed of light is 3 x 10¹⁰ cm/s.
   1. How fast do X-rays with a wavelength of 10^-6 cm travel in space?
   2. What is the frequency of these X-rays?
2. The star Capella is 12 pc away. The star Regulus is 24 pc away. It is known that both stars are very similar and have approximately equal luminosities. Which star appears brighter to us, and by what factor?
3. Vega is a main sequence star, as is the Sun, but Vega has a luminosity about 40 times that of the Sun and a mass about 3 times that of the Sun. Which star will live longer, and by what factor?
4. Which star, Vega or the Sun, has a larger habitable zone, i.e., region in which an Earth-like planet could retain liquid water?
5. Of all the spectral types, which type is the most abundant in our Galaxy?
6. What spectral type is the Sun?
7. Why do collapsing, rotating, gas clouds flatten into pancake-like shapes?
8. What is the reason that elements like Fe are more abundant in solid materials in the inner solar system than in the outer solar system?
9. Where are most asteroids in the solar system located?