2
17
26
35
46
57
74
80
83
87
103
110
122
125
129
139
155
158
171
190

THE GAS THAT IS ABOVE THE PLANET'S
SURFACE

ONLY THE LARGER PLANETS AND MOONS
HAVE ENOUGH GRAVITY TO HAVE AN
ATMOSPHERE

SOMETIMES THE ATMOSPHERE IS MADE OF
EVAPORATED MATERIAL FROM THE
OBJECT'S SURFACE

CO2 MEANS CARBON DIOXIDE

LIFE AS WE KNOW IT REQUIRES OXYGEN,
WHICH ONLY EARTH HAS
AVERAGE WEIGHT PER UNIT VOLUME OF
THE OBJECT

WATER HAS A DENSITY OF 1 GRAM PER 
CUBIC CENTIMETER

OBJECTS WITH A LOWER DENSITY WILL
FLOAT IN WATER; THOSE WITH A GREATER
DENSITY WILL SINK
WHEN AND BY WHOM THE OBJECT WAS
FIRST OBSERVED

THE SUN, MOON AND THE FIRST SIX
PLANETS CAN BE OBSERVED WITH A NAKED
EYE AND WERE KNOWN TO EARLY PEOPLE
 
THE OTHER PLANETS AND MOONS REQUIRED
TELESCOPES TO BE OBSERVED
AVERAGE DISTANCE BETWEEN A GIVEN
MOON AND ITS PLANET

A KILOMETER (KM) IS 0.6 MILES

A TYPICAL AIRPLANE TRAVELS 900 KM
PER HOUR

LIGHT TRAVELS 300,000 KM PER SECOND
OR ABOUT A MILLION TIMES FASTER THAN
AN AIRPLANE
AVERAGE DISTANCE BETWEEN A PLANET
(AND ITS MOONS) AND THE SUN

A KILOMETER (KM) IS 0.6 MILES

A TYPICAL AIRPLANE TRAVELS 900 KM
PER HOUR

LIGHT TRAVELS 300,000 KM PER SECOND
OR ABOUT A MILLION TIMES FASTER THAN
AN AIRPLANE
MISCELLANEOUS FACTS AND FEATURES
INCLUDING -- PHYSICAL APPEARANCE OR
FEATURES, ORDER OF MOON FROM PLANET

DEFINITIONS:  

SCARP: SCALLOPED CLIFF 

CRATER:  BOWL-SHAPED PIT
USUALLY CAUSED BY A METEOR IMPACT

ECCENTRIC ORBIT: ELONGATED
ELLIPTICAL ORBIT 

EQUATOR AND ORBIT PERPENDICULAR: 
OBJECT APPEARS TO ROLL RATHER THAN
SPIN
YOUR RELATIVE WEIGHT ON THAT OBJECT
COMPARED TO EARTH

ALSO INDICATES HOW FAST SOMETHING
WILL FALL TOWARDS THE OBJECT OR HOW
HARD IT IS TO BLAST OFF THE OBJECT
THE WEIGHT OF A PLANET COMPARED TO
EARTH OR THE WEIGHT OF A MOON
COMPARED TO EARTH'S MOON
MAKE UP OF OBJECT (OR ITS SURFACE)
FOR EXAMPLE, ROCK OR ICE

SO2 IS SULFUR DIOXIDE
FOR WHOM OR WHAT THE OBJECT WAS
NAMED

MOST OF THE PLANETS AND MOONS
WERE NAMED FOR GREEK OR ROMAN GODS
OR GODDESSES

JUPITER IS NAMED FOR THE KING OF THE
GODS BECAUSE OF ITS SIZE

MARS IS NAMED FOR THE GOD OF WAR
BECAUSE IT IS RED

MERCURY IS NAMED FOR THE MESSENGER
TO THE GODS BECAUSE IT MOVES
QUICKLY ACROSS THE SKY
THE NUMBER OF MOONS THAT HAVE SO FAR
BEEN DISCOVERED

THESE NUMBERS HAVE CHANGED BECAUSE
OF NEWLY DISCOVERED MOONS FROM
BETTER TELESCOPES AND THE PIONEER
AND VOYAGER SPACECRAFT
THE TIME FOR THE PLANET TO GO ONCE
AROUND THE SUN OR FOR A MOON TO GO
ONCE AROUND ITS PLANET (THE OBJECT'S
"YEAR")

THE EARTH TAKES ONE YEAR TO ORBIT
THE SUN

SOME MOONS ORBIT THEIR PLANETS IN A
RETROGRADE ORBIT, WHICH IS BACKWARDS
WITH RESPECT TO THE PLANET'S
ROTATION
THE ORDER OF THE PLANETS FROM
CLOSEST TO THE SUN (MERCURY) TO
FURTHEST (PLUTO)
A PHOTOGRAPH OF THE PLANET (IF ONE
HAS BEEN TAKEN BY NASA) OR AN
ARTIST'S CONCEPTION (FOR CERES,
PLUTO AND CHARON)
THE DISTANCE FROM THE CENTER OF THE
OBJECT TO ITS SURFACE

ALL OF THE OBJECTS LISTED ARE
SPHERICAL EXCEPT FOR PHOBOS AND
DEIMOS WHICH ARE TOO SMALL TO BECOME
SPHERICAL AND THEREFORE ARE LIKE
IRREGULAR CHUNKS OF ROCK

A KILOMETER IS 0.6 MILES
THE TIME IT TAKES FOR THE OBJECT TO
ROTATE OR SPIN ON ITS AXIS (THE
OBJECT'S "DAY")

THE EARTH TAKES ONE DAY TO ROTATE ON
ITS AXIS

ALL THE MOONS WHOSE ROTATIONAL
PERIODS ARE KNOWN HAVE THEIR ORBITAL
AND ROTATIONAL PERIODS THE SAME
WHICH MEANS THAT THE SAME SIDE OF
THE MOON ALWAYS FACES THE PLANET

PLUTO AND CHARON HAVE THE SAME
ROTATIONAL PERIOD WHICH MEANS THAT
ONE SIDE OF PLUTO NEVER FACES CHARON
THE RELATIVE SIZE OF THE PLANETS
FROM LARGEST (JUPITER) TO SMALLEST
(PLUTO)
THE MAJOR SPACECRAFT THAT HAVE COME
NEAR TO THE OBJECT

ALL OF THE PLANETS HAVE BEEN VISITED
EXCEPT FOR PLUTO AND THE ASTEROID
BELT

MORE SPACECRAFT ARE ON THE WAY OR
ARE PLANNED FOR THE SUN, JUPITER AND
SATURN

NONE ARE CURRENTLY PLANNED FOR
CERES, PLUTO OR CHARON
A MEASURE OF HOW HOT THE OBJECT IS

FOR SOME OBJECTS (MERCURY AND THE 
MOON) THE DAYTIME AND NIGHTTIME 
TEMPERATURES ARE VERY DIFFERENT

FOR OBJECTS WITHOUT A WELL-DEFINED
SURFACE, AN EFFECTIVE TEMPERATURE IS
GIVEN -- THIS IS THE TEMPERATURE THE
OBJECT WOULD APPEAR TO BE

ZERO DEGREES C (CELSIUS) IS THE
FREEZING POINT OF WATER (32 DEGREES
FAHRENHEIT); 100 DEGREES C IS THE
BOILING POINT OF WATER (212 DEGREES
FAHRENHEIT)

GENERALLY OBJECTS ARE HOTTER THE
CLOSER THEY ARE TO THE SUN
