Across
- 1. This layer of the Moon is actually much thinner on the side that faces the Earth than on the far side.
- 7. This theory of the origin of the Moon states that the Moon and Earth were "twins", forming side by side from a common cloud of gas and dust.
- 8. These objects are long, light streaks of pulverized rock that extend out of craters.
- 10. The large, smooth, dark areas of the Moon's surface are called this, from the Latin word for "seas."
- 11. Lunar scientists have detected only tiny quantities of gas above the Moon's surface. Most of the gas is this element.
- 14. When the Moon is more than half lit, it has this shape.
- 15. This theory of the origin of the Moon states that the Earth initially spun enormously faster than now and formed a bulge that ripped away from the Earth to become the Moon.
- 17. When an eclipse occurs, this happens at the time when the Moon's disk completely covers the Sun.
- 19. The difference in rocky material between the maria and highlands were discovered by samples collected by astronauts of this mission.
- 20. Sometimes an eclipse is _______, with only a portion of the Moon or the Sun ever being covered over.
- 22. These are the large circular pits located in bright areas on the Moon.
- 24. The second reason why the Moon lacks an atmosphere is because the Moon's ________ is too weak to retain gas for long.
- 25. When growing from a new phase, the Moon will next take this shape in its sequence of lunar phases.
- 26. A _____ ________ occurs whenever the Moon passes directly between the Sun and the Earth and blocks our view of the Sun.
- 27. A _____ ________ occurs when the Earth passes between the Sun and the Moon and casts its shadow on the Moon.
Down
- 2. As it orbits, the Moon keeps the same side facing the Earth. The Moon does turn on its axis but with a rotation period exactly equal to its orbital period. This condition is known as ___________ _____________.
- 3. These tides are abnormally large tides that occur during the Moon's new and full phases.
- 4. The bright areas that surround the maria are called _______________. This region differs from maria in brightness because they are composed of different rock types.
- 5. Since the Moon exerts a stronger force on one side of Earth and a weaker force on the other side of Earth, the difference in force overall is called this 3 word term.
- 6. Tides create forces on the Earth and the Moon that slow their rotation. This phenomenon is known as __________ __________________.
- 9. When talking about moon phases, at the beginning of the phases, the Moon grows or ______ from invisibility.
- 12. The Moon lacks this kind of field, suggesting that the core is at most partially molten. This is also due to a small amount of iron in its core.
- 13. This is known as the regular change in the height of the ocean and is caused mainly by the Moon.
- 16. These tides are not as extreme as normal high and low tides and occur during a Moon's first and third quarters.
- 17. The reason why we do not have an eclipse every lunar cycle is because of the ______ of the Moon's orbit, and because it remains fixed over time.
- 18. Sometimes, the Moon is so far away that its shadow does not reach the Earth. This will cause an eclipse where a ring of sunlight is seen as the Sun is setting. This is the name of this eclipse.
- 21. The first reason why the Moon lacks an atmosphere is because its interior is too cool to cause much _______ activity.
- 22. This theory of the origin of the Moon states that the Moon was originally a small planet orbiting the Sun. It approached the Earth and was captured by Earth's gravitational pull.
- 23. This term, meaning blanket of rock, consists of rock chunks and fine powder, the result of successive impacts breaking rock into smaller and smaller pieces.