Answer:
1. a) Astronomers use the parallax method to measure the distance to nearby stars, but
we can’t use it to measure the distance to stars in other galaxies. Why not? Why isn’t the
parallax method useful for measuring the distances to stars in other galaxies?
They are so distant that the parallax is too small to be measured since parallax varies
inversely with distance.
b) Instead of the parallax method, we use the standard candle method to measure the
distance to stars in other galaxies. In particular, we use the standard candle method to
measure the distances to Cepheid variable stars in other galaxies. What is special about
Cepheid variable stars that makes them useful for this purpose?
We can figure out their luminosities from their periods of variation. Then if we measure
their fluxes we can calculate their distances.
2. a) From what were the protons and electrons in your body made, and roughly when
were they made?
They were made from energy (or gamma rays) very soon after the big bang (in the first
second). 400,000 years later they got together to make hydrogen atoms.
b) From what were the carbon atoms in your body made, and where were they made?
They were not made in the big bang. They were made much later inside of stars or in
supernovae. They were made by fusion from lighter atoms.
3. Make two sketches of the Milky Way Galaxy, one an edge-on view and one a face-on
view, labeling the various parts of the galaxy.
You should have labeled the
