Astr 104, Spring 2008 – Quiz 10

1. What is dark matter?
a. The matter out of which black holes are made.
b. Matter whose gravity repels rather than attracting.
c. Clouds of dust responsible for the fact that the sky is dark at night.
d. Matter that we detect only by its gravitational pull on other objects.

2. According to current ideas, what is the approximate composition of the universe?
a. 95% regular matter, 5% dark matter.
b. 10% regular matter, 90% dark energy.
c. 50% regular matter, 30% dark matter, 20% dark energy.
d. 5% regular matter, 25% dark matter, 70% dark energy.

3. What is the main evidence we have that the universe started with a hot big bang?
a. The cosmic microwave background.
b. The existence of dark matter.
c. The age of the globular clusters in our galaxy.
d. The high temperatures still found in the cores of many galaxies.

4. How long after the Big Bang did the first stars and galaxies form?
a. A few seconds.
b. Three minutes.
c. 300,000 years.
d. Several hundred million years.

5. According to the best cosmological evidence, approximately how long has it been since the Big Bang?