Outer Space

3. ________ planets are farthest from the sun and include: Jupiter, Saturn, Uranus, and Neptune.
4. The only place in our solar system, other than Earth, where humans have visited.
5. Small icy bodies.
7. The Milky Way ________ contains our solar system.
8. temperature
11. The Astronomical ________ is the distance from the center of the Earth to the center of the Sun.
14. An asteroid ________ divides the Inner and Outer Planets.
16. The Greenhouse _____________ is an increase in temperature caused when incoming solar radiation is passed but outgoing thermal radiation is blocked by the atmosphere.
17. The length of time required for a planet to make one complete trip around the Sun.
18. The circular path a planet takes around the sun.
19. The _______ planets are composed primarily of hydrogen and helium.
21. position
23. _______ planets are closest to the sun and include: Mercury, Venus, Earth, Mars.
24. _________ is the force by which a planet or other body draws objects toward its center.

1. Bright streak of light that results when a meteoroid burns up in the Earth’s atmosphere-sometimes called a “shooting star”.
2. The ________ planets are composed of rock and metal.
6. A __________ is a celestial body that orbits the sun and has a gravitational pull.
9. Small rocky bodies.
10. Meteoroid that reaches Earth’s surface without burning up completely.
12. small, rocky body that travels through space
13. The solar system formed from a collapsing cloud of gas and dust called a _________.
15. The length of time required for a planet to make one complete turn on its axis.
20. ________ is defined as the ratio of the mass of an object to the volume of space the object takes up.
22. ________ planets are objects that are similar to planets except that they orbit the Sun in areas where there are many similar objects