The difference between an asterism and a constellation is that an asterism is:

a. a group of stars bound together by gravity, whereas those in a constellation are not.

b. a group of stars, whereas a constellation is an area of the sky.

c. a group of stars represented by an easily recognized object, whereas a constellation is a group of stars represented by some abstract or imaginary figure.

d. the formal astronomical listing of a group of stars, whereas a constellation is a popular name for the group of stars usually inherited from ancient sky-watchers.

Which of the following statements about the sky is TRUE?

a. The distances to two stars must first be known in order to determine their separation distance.

b. Polaris was not always located at the North Pole.

c. The celestial sphere is located at the edge of the solar system, about the distance to Pluto.

d. The zenith is a point on the celestial sphere directly over Earth's North Pole.

An object with an apparent visual magnitude of +12 is:

a. similar in brightness to the full Moon.

b. 100 times brighter than an object whose magnitude is +17.

c. emitting 100 times less energy than an object whose magnitude is +17.

d. 12 times brighter than the dimmest star observable with the human eye.

Our system of expressing direction on Earth (i.e., N, S, E, W) is based on:

a. the star Polaris.

b. Earth's rotation.

c. the axial tilt of Earth.

d. the zenith.

Earth's axis is tilted from the perpendicular of its orbit. A consequence of this is that:

a. Earth and the moon are slowly separating from one another.

b. Earth is not always closest to the sun at the same time of the year.

c. Earth wobbles as it rotates, causing precession.

d. Earth experiences seasons