| A | B |
|---|
| ASTEROIDS | SMALL ROCKY BODIES THAT ORBIT THE SUN BETWEEN THE ORBITS OF MARS AND JUPITER. |
| ASTRONOMER | A SCIENTIST WHO STUDIES THE PLANETS, STARS, AND OTHER CELESTIAL OBJECTS IN ORDER TO UNDERSTAND THE UNIVERSE. |
| ASTROMICAL UNIT (AU) | THE DISTANCE BETWEEN THE EARTH AND THE SUN, ABOUT 93 MILLION MILES. THIS UNIT IS USED FOR MEASURING DISTANCES IN THE SOLAR SYSTEM. |
| AXIS | AN IMAGINARY LINE AROUND WHICH A PLANET ROTATES. |
| CIRCUMPOLAR | AROUND THE POLES. CIRCUMPOLAR STARS ALWAYS APPEAR TO CIRCLE EITHER THE NORTH CELESTIAL OR THE SOUTH CELESTIAL POLE. |
| COMETS | CHUNKS OF ICE AND ROCK THAT TRAVEL AROUND THE SUN IN A VARIETY OF ORBITS. SOME OF THE ORBITS ARE VERY LONG AND SOME ARE SHORT. |
| CONSTELLATION | SOME KIND OF PICTURE FORMED BY STARS, |
| CORE | THE CENTRAL PART OF ANY STAR. |
| CORONA | THE UPPERMOST GASEOUS LAYER OF THE SUN'S ATMOSPHERE. |
| CRATER | A DEEP IMPRESION LEFT IN THE SURFACE OF A PLANET OR MOON BY THE IMPACT OF A METEOR. |
| ECLIPSE | A TEMPORILARY BLOCKING OF THE SUN OR MOON. |
| ELLIPSE | A FLATTNED CIRCLE. |
| EQUINOX | A DAY, OCCURING ONCE IN THE SPRING AND ONCE IN THE FALL WHERE THERE IS AN EQUAL AMOUNT OF DAY LIGHT AND DARKNESS. |
| GALAXY | A VAST COLLECTION OF STARS. |
| GRAVITY | THE FORCE OF ATTRACTION BETWEEN EVERY PARTICLE OF MATTER AND EVERY OTHER PARTICLE OF MATTER.CLE |
| LIGHT-YEAR | 6 TRILLION MILES...HOW MANY MILES LIGHT TRAVELS IN A YEAR |
| MAGNITUDE | THE DEGREE OF BRIGHTNESS OF A STAR. |
| METEOR | A METEROID THAT ENTERS EARTH'S ATMOSPHERE. |
| METEORITE | A METEOR THAT PLUNGES TO EARTH IN ONE PIECE. |
| METEROID | DUS, GAS PARTICES, AND ROCKS THROWN OFF BY COMETS |
| MOON | THE EARTH'S NATURAL SATTELITE. |
| ORBIT | THE PATH ONE OBJECT TAKES AROUND ANOTHER, SUCH AS THE PATH OF THE SUN OR MOON AROUND EARTH. |
| PHASE | ONE OF THE APPARENT SHAPES OF THE MOON. |
| PLANET | ONE OF THE LARGE NINE LARGE, SOLID, NEARLY SPHERACAL OBJECTS RELVOLVING AROUND THE SUN. |
| REVOLUTION | THE MOVEMENT OF ONE ONE OBJECT AROUND ANOTHER. |
| ROTATION | THE SPINNING OF A BODY ABOUT ITS AXIS. |
| SATELLITE | A NATURAL OR ARTIFICIAL BODY THAT ORBITS ANOTHER BODY. |
| SOLAR SYSTEM | THE SUN, ITS FAMILY OF PLANETS, AND ALL THE ASTEROIDS, COMETS, AND METEORS. |
| SOLSTICE | A DAY THAT HAS THE MOST HOURS OF SUNLIGHT OR THE FEWEST HOURS OF SUNLIGHT. |
| STAR | A LARGE GLOBE OF HOT GASSES. |
| SUN | THE SUN IN OUR SOLAR SYSTEM |
| UNIVERSE | EVERYTHING THERE IS. |
