Earth in Space

2. a push or pull that acts on an object, changing its speed, direction, or shape
3. the rate at which an object covers distance in a period of time
4. the measurement of an object's mass multiplied by its speed
6. the changing appearance of the moon (as seen from Earth) as it orbits Earth
8. a large cluster of stars held together by gravity
11. the relationship between things, as to size, quantity, or number
14. to travel in a circle around an object
15. the four gas planets of the outer solar system (Jupiter, Saturn, Uranus, and Neptune)
17. the wide-open space that holds all matter and energy known to exist

1. the four rocky planets of the inner solar system (Mercury, Venus, Earth, and Mars)
5. a body that orbits the sun, is massive enough for its own gravity to make it round, and has cleared out smaller objects around its orbit
7. occurs when one object in the solar system moves into the shadow of another object
9. a collection of planets and other objects that orbit a sun
10. the attractive force between all matter
12. a period of time characterized by specific weather patterns and by the length of day and night
13. a gravitational force exerted on an object by a planet or moon; measured in newtons (N)
16. a star at the center of a solar system