3. A waning moon refers to the phases after a full moon, but before a new moon. A waxing moon refers to the phases after a new moon, but before a full moon. A gibbous phase shows more than half-full moon, whereas a crescent moon shows less than a half-moon.

5. A lunar eclipse is the result of the earth's shadow falling on the moon. Anyone that has a view of the moon when this happens can see the eclipse. A solar eclipse is the result of the moon's shadow falling on the earth. This shadow only covers a small portion of the earth's surface that faces the sun. In order to see the lunar eclipse you must be with that shadow.

8. Thermonuclear fusion gives the sun its energy. The fusion is the result of extreme gravitational forces within its center.

16. There is an error in the book. The problem should read:

Jupiter has more than 300 times the mass of the earth....

Note: Jupiter's diameter is 10 times that of earth, also recall gravity obeys the inverse square law i.e. twice the distance means one fourth the gravity. So, (about 300 times the mass of earth)/(10 times the distance, squared) gives us about 3 times earth's gravity.

20. The poles of Uranus almost lie in the its orbital plane, whereas the poles of the other planets are nearly perpendicular to their orbital plane.

21. Neptune was the first planet discovered beyond Uranus, and Pluto the second. Likewise, Neptunium was the first element discovered beyond uranium, and plutonium second.

22. Antarctica, because most would be embedded in the ice.

23. The comet occupies a very small part of the sky. With all the other points of light out there, it is very difficult to spot the new one. Consider a 'Where's Waldo' poster the size of Muncie.