| A | B |
|---|
| terrestrial | small, dense, and rocky planets |
| jovian | large, gaseous, and no solid surface |
| asteroid belt | located between Mars and Jupiter |
| astronomical unit | distance from the sun to the planet |
| satellites | artificial or natural bodies revolving around larger bodies |
| Thea | early planet that crashed into Earth, making our moon |
| full moon | when the earth is between the sun and moon |
| solar eclipse | event that occurs during a new moon |
| apogee | when the moon is the farthest away from earth |
| perigee | when the moon is the closest to earth |
| waxing | when the moon appears to be growing each night |
| waning | when the moon is going from full moon to new moon |
| lunar eclipse | a more common event that is viewed at night |
| comets | "dirty snowballs" |
| asteroids | similar to meteoroids, but much larger |
| meteors | "shooting stars" |
| meteorites | space rock that strikes the earth's surface |
| dwarf planet | pluto |
| Sputnik | first satellite in space |
| Yuri Gagarin | first man in space |
| Alan B. Shephard Jr. | first American in space |
| President Kennedy | created the Apollo program |
| President Nixon | created the Space Shuttle program |
| Neil Armstrong | first man to walk on the moon |
| space shuttles | reusable space vehicle |
| International Space Station | research facility orbiting the earth |
| Columbia | exploded in 2003 during re-entry |
| Challenger | exploded in 1986 after launch |
| private-company space flights | new objective for NASA |
| build the ISS | main purpose for the space shuttles |
