Across
- 3. A __________ is a streak of light formed by a space rock burning up as it plunges into Earth's atmosphere.(243)
- 6. A light year is the ________________ light travels in a year.(245)
- 7. The different shapes that the moon appears to have are called the moon's _______________.(235)
- 8. The ________ giants are planets that have surfaces made of a kind of slush that forms from their gaseous atmospheres.(240)
- 10. Earth's ________ is an imaginary line that runs from the North Pole to the South Pole.(233)
- 11. Nuclear ______________ reactions occur when hydrogen atoms combine to form helium atoms.(245)
- 14. An __________________ galaxy does not have a distinct shape.(247)
- 15. If a rock from space strikes the Earth's surface, it is called a ___________________________.(243)
- 16. Terrestrial ________________ are those having rocky surfaces and cores made of iron.(240)
- 18. A _____________ is a mixture of frozen gases and tiny particles of dust.(242)
- 20. An _________________ occurs when one object in space casts a shadow on another.(236)
- 21. An _______________ galaxy is shaped like a flattened football.(247)
Down
- 1. Dish-shaped pits formed when objects from space struck the surface.(239)
- 2. A ____________ is a natural satellite of a planet.(239)
- 4. _____________ are changes in ocean water levels that take place in a regular pattern.(237)
- 5. Each complete spin, or _______________ of the Earth takes 24 hours.(233)
- 9. After moons, the next largest objects in the solar system are large rocks called __________________.(241)
- 12. The ____________ system includes the sun and all the objects in space affected by the sun's gravity.(238) (238)
- 13. A ________________ is an object that stays in an orbit around a planet. (230)
- 17. A ____________ galaxy is disk-shaped with a bulge in the middle and arms that spiral out from the bulge.(247)
- 19. The path a moon or planet follows as it moves around the sun is called its ________________.(234)