Download Chapter 23 Vocabulary

Chapter 23 Vocabulary
1. solar system- system of nine planets and many other objects that orbit our sun
2. inner planets- the four solid, rocky planets closest to the sun; Mercury, Venus,
Earth, and Mars
3. Mars- in our solar system, the fourth planet from the sun
4. Jupiter- in our solar system, the fifth planet from the sun; largest planet, mostly
gas and liquid
5. comet- moss of frozen gasses and rock particles that orbits the sun, often
developing a bright tail when it passes near the sun
6. Oort Cloud- cloud of comets surrounding the solar system outside Pluto’s orbit;
may be the source of most comets
7. outer planets- five planets farthest from the sun- Jupiter, Saturn, Uranus,
Neptune, and Pluto
8. Earth- in our solar system, the third planet from the sun; only planet known to
support life
9. Venus- in our solar system, the second planet from the sun; very similar to Earth
in size, is blanketed with thick clouds, and is very hot
10. Saturn- in our solar system, the sixth planet from the sun; second largest planet,
is mostly gas and liquid, has prominent rings
11. Uranus- in our solar system, the seventh planet from the sun. large, gaseous, and
the only planet that “lays on its side” in orbit
12. Pluto- in our solar system, usually the ninth and last planet from the sun
13. Neptune- in our solar system, usually the eighth planet from the sun, large and
gaseous
14. Mercury- in our solar system, first planet from the sun, second smallest planet,
has a cratered surface like our moon
15. astronomical unit (AU)- average distance from earth to the sun (150, 000,000
km), used for measuring distances to objects in the solar system
16. Great Red Spot- giant storm in Jupiter’s atmosphere
17. meteoroid- small pieces of rock that orbit the sun, resulting from the breakup of
comets
18. meteor- meteoroid that enters Earth’s atmosphere and burns up as it falls
19. meteorite- meteor that reaches Earth’s surface
20. asteroid- piece of rock, smaller than a planet, that orbits the sun; most are
between the orbits of Mars and Jupiter