1. According to Newton's Law of Gravity, if you take two objects and separate them so they end up 4 times farther from each other than they started, what has happened to the force of gravity between them?

a. It is 16 times weaker.

b. It is 4 times weaker.

c. It is 2 times weaker.

d. The force of gravity hasn't changed, since the masses of the two objects hasn't changed.

2. If Humans were to send a message to some friendly aliens living on an Earth-like planet orbiting the nearest star, Alpha Centauri, how long would we have to wait after sending the message to get their response?

a. 8.8 years.

b. 4.4 years.

c. 2.2 years.

d. It would depend on how many other people were on-line at the same time.

3. About how many stars are there in our Galaxy?

a. Less than a million.

b. About 50,000.

c. About 100 million.

d. More than 100 billion

4. Which of the following is not evidence for the Big Bang theory?

a. The fact that nearly all galaxies in the Universe are moving away from each other.

b. The cosmic microwave background radiation.

c. The fact that the Universe is mostly three-fourths hydrogen and one-fourth helium.

d. The fact that the Sun is about 4.5 billion years old.

5. Which of the following astronomical objects is the largest ?

a. A planet.

b. A star.

c. A galaxy.

d. A galaxy cluster.