1. How are Cepheid variables used to measure distances?
2. The parallax method fails for large distances because
a) The orbit of the Earth is not known to a good accuracy
b) The angles measured become too close to 90 degrees
c) The distant stars are too dim
d) The 1/r2 rule fails
e) The motion of the Solar System around the galaxy needs to be taken into account and that is not well known
3. Imagine a yellow star that is orbiting a very compact and massive object that does not emit visible light. An astronomer on Earth would see (assume that the orbit is slanted as seen from Earth)
a) A yellow star
b) A red star
c) A blue star
d) A star that is first a little redder, then a little bluer, and that this pattern repeats periodically
e) Nothing, since the light of the star cannot leave the vicinity of the compact object.
4. Imagine a cloud of very hot hydrogen gas in space that is emitting light, but before this light gets to Earth it has to go through a very cold and very dense cloud also of hydrogen, an astronomer on Earth will see
a) Light in a few specific colors
b) A smooth rainbow of colors
c) Nothing
d) White light with a few colors removed
e) White light
5. The cosmic background radiation is
a) The result of the emission of many stars
b) A result of the cosmological constant
c) The result of gas emissions throughout the universe
d) A result of the creation of the early elements in the early universe
e) The red-shifted radiation from the time atoms were first formed in the early universe
6. One of the puzzles the inflationary hypothesis aims to solve is
a) The existence of the cosmic background radiation
b) The uniformity of the cosmic background radiation
c) The existence of the cosmological constant
d) The abundances of light elements
e) The existence of dark matter
7. In the early universe
a) All elements were manufactured
b) Only light elements were manufactured
c) All elements were manufactured, but only the light ones were not subsequently destroyed
d) No elements were manufactured, this happened later once stars started to form
e) Only hydrogen was manufactured
8. An unconfirmed prediction of the Big Bang theory is
a) That the universe should be immersed in a bath of microwaves
b) That the universe should be expanding or contracting
c) A significant amount of matter in the universe should take the form of dark matter
d) That the cosmological constant should not be zero
e) That the universe should be immersed in a bath of slowly moving neutrinos
9. The “horizon puzzle” results form the observation that
a) Only light elements were created in the early universe
b) We cannot see infinitely far away into space
c) The cosmic background radiation presents small non-uniformities
d) Black holes do not allow light to leave once it comes too close to them
e) Regions of the universe that apparently have not been in contact have identical average properties
10. The dark matter hypothesis was proposed in order to
a) Understand the uniformity of the cosmic background radiation
b) The behavior of stars orbiting galaxies
c) The incontrovertible observation that the density of the universe is far below the critical value
d) Understand violations of the cosmological principle
e) Explain why gravity is not always attractive