Which Apollo spacecraft landed on the Moon in February 1971?

Which of the following statements does not use the term light-year in an appropriate way?
A) A light-year is about 10 trillion kilometers.
B) It's about 4 light-years from here to Alpha Centauri.
C) It will take the Voyager spacecraft about 20,000 years to travel just 1 light-year.
D) The Milky Way Galaxy is about 100,000 light-years in diameter.
E) It will take me light-years to complete this homework assignment.

Orion is visible on winter evenings in the northern hemisphere but not summer evenings because of

a. interference from the full Moon

b. the tilt of Earth's axis

c. the location of Earth in its orbit

d. the precession of Earth's axis

Which of the following statements about the celestial sphere is not true?

a. The celestial sphere does not exist physically.
b. When we look in the sky, the stars all appear to be located on the celestial sphere.
c. The Earth is placed at the center of the celestial sphere.
d. The "celestial sphere" is another name for our universe.