Earth, Sun, and Moon

4. The time or date at which the sun crosses the celestial equator, when day and night are of equal length
6. A gradual decrease in magnitude or extent
9. Each of the twelve named periods into which a year is divided
12. The vertical difference between the high tide and the succeeding low tide
13. A colorless, odorless, flammable gas
17. Created the theory that the Earth was at the center of the universe and that the sun and the other planets all revolved around the Earth
18. The process of combining two or more things together into one
20. Having or representing the sun as a center
22. Having or representing the earth as a center
23. A tide just after the first or third quarters of the moon when there is the least difference between high and low water
25. A natural body that revolves around a planet

1. The fully shaded inner region of a shadow cast by an opaque object
2. The partially shaded outer region of the shadow cast by an opaque object
3. The large rise and fall of the tide at or soon after the new or the full moon
5. To move or cause to move into a sloping position
7. Force that attracts a body to the center of the earth, or to any other physical body having mass
8. An eclipse in which the moon appears darkened as it passes into the earth's shadow
10. A spot or patch appearing from time to time on the sun's surface, appearing dark by contrast with its surroundings
11. A period of 365 or 366 days
14. A period of twenty-four hours as a unit of time
15. Proved that other galaxies existed beyond the Milky Way
16. An eclipse in which the sun is obscured by the moon
19. A gradual increase in magnitude or extent
21. One of the first people to use a telescope to observe objects in space
24. A distinct period or stage in a process of change or forming part of something's development