Unit 8 Vocabulary

3. a device that is used to obtain information from outer space and send it back to Earth
6. a device without people on it that is designed for travel or operation outside of the Earth’s atmosphere
12. spinning of a planet, moon, sun, or another object around its axis
15. sun-centered
16. a spherical region that surrounds the solar system
17. objects of rock, metal, and ice that are smaller than planets and revolve around the Sun
20. object that revolves around a larger object in space
21. a unit used to measure distances in the Solar System equal to the average distance between the Earth and Sun

1. force of gravity between two objects increases as the mass of the objects increases and as the distance between them decreases
2. oval shaped
4. a small body from which a planet originated in the early stages of development of the solar system
5. a natural object that revolves around a planet
7. a piece of rock from space the enters Earth’s atmosphere and burns, creating a bright streak of light across the sky
8. the region of interplanetary space between the orbits of Mars and Jupiter in which most asteroids are found
9. solar system object made of ice, which follow a long, narrow orbit around the Sun dwarf planet: a celestial body similar to a planet by orbiting in a zone that has many other objects in it
10. one orbit of an object in space around another object in space
11. a relatively large spherical body that surrounds a star
13. a piece of a meteor that breaks off and lands on the Earth meteoroid: a relatively small, rocky body that travels through space
14. one of the large planets made mostly of gas geocentric: describes something that using Earth as the reference point gravitational force: force of attraction between two objects
18. rocky planets in the inner solar system
19. a rotating cloud of gas and dust from which the sun and planets formed