Transcript Slide 1
The Outer Planets The Gas Giants JUPITER DISTANCE FROM SUN = 5.2 AU MASS = 318 X EARTH DIAMETER = 11 X EARTH ATMOSPHERE = HYDROGEN AND HELIUM SURFACE = LIQUID HYDROGEN ORBIT = 12 YEARS ROTATION = 10 HOURS MOONS = 63 (4 GALILEAN MOONS) ONE OBVIOUS FEATURE IS THE GREAT RED SPOT, WHICH IS LARGE ENOUGH TO PUT TWO EARTHS IN SIDE-BY-SIDE. IT IS A LARGE STORM, AND IT HAS LASTED FOR OVER 300 YEARS. Io, Europa, Ganymede, and Callisto TIDAL FORCES HEAT THE INTERIOR OF THE TWO INNERMOST MOONS. IO HAS TREMENDOUS VOLCANIC ERUPTIONS. IO IS 2% LARGER THAN EARTH’S MOON. EUROPA HAS A SHELL OF WATER ICE, WHICH IS ESTIMATED TO BE BETWEEN 12 AND 90 mi THICK. EUROPA IS ABOUT 12% SMALLER THAN EARTH’S MOON. CASTILLO AND GANYMEDE ARE BOTH SLIGHTLY LARGER THAN THE PLANET MERCURY. BOTH MAY HAVE LIQUID OCEANS DEEP BENEATH THEIR ICY CRUSTS. JUPITER MAY HAVE A ROCKY IRON/NICKEL CORE 1.5 TIMES EARTH’S DIAMETER. DUE TO THE EXTREME GRAVITY, THE CORE TEMPERATURE MAY BE AS HIGH AS 20,000o C. SATURN DISTANCE FROM SUN = 9.5 AU DIAMETER = 9.4 EARTH MASS = 95 X EARTH ORBIT = 29.5 YEARS ROTATION = 11 HOURS THOUGHT THAT SATURN HAS A CORE APPROX. 2.5 TIMES EARTH’S DIAMETER, 20 TIMES EARTH’S MASS, AND 15% OF SATURN’S TOTAL MASS. THE PLANET IS MADE MOSTLY OF MOLECULAR HYGROGEN (88%) AND HELIUM (11%). SATURN’S RINGS ARE VERY THIN. THEY ARE 250,000 km ACROSS, BUT THEY ARE ONLY 1 km THICK. THERE IS NOT MUCH MATERIAL THERE. IF IT WERE ALL COMPRESSED INTO A SINGLE OBJECT, IT WOULD ONLY BE 100 km THICK. LIKE JUPITER, SATURN RADIATES MORE ENERGY THAN IT RECEIVES FROM THE SUN. ALSO, LIKE JUPITER, SATURN HAS A STRONG MAGNETIC FIELD. SCIENTISTS THINK THIS IS CAUSED BY THE METALLIC HYDROGEN IN THE INTERIOR. TITAN IS THE LARGEST MOON OF SATURN. IT HAS AN ATMOSPHERE COMPOSED MOSTLY OF NITROGEN AND METHANE. THE ATMOSPHERIC PRESSURE AT THE SURFACE IS 1.6 TIMES THAT OF EARTH. THE SURFACE OF TITAN IS COVERED WITH HYDROCARBON LAKES, PRIMARILY METHANE AND ETHANE. PICTURE OF TITAN SHOWING ITS ATMOSPHERE. SATURN WAS THE FURTHEREST PLANET FROM THE SUN KNOWN TO THE ANCIENTS. URANUS WAS NOT DISCOVERED UNTIL 1781 BY WILLIAM HERSCHEL USING A TELESCOPE. URANUS DIAMETER = 4 X EARTH MASS = 11 X EARTH DISTANCE FROM SUN = 19.2 AU ROTATION = 17 HOURS ORBIT = 84 YEARS THE ROTATIONAL AXIS IS ONLY 8 DEGREES OUT OF THE PLANE OF THE ORBIT, SO WE SEE IT ON ITS SIDE. COMPOSITION = MOSTLY HYDROGEN AND HELIUM. MOONS = 5 LARGE AND 10 SMALL THE BLUE COLOR IS DUE TO METHANE IN THE ATMOSPHERE. URANUS HAS A MAGNETIC FIELD ABOUT 50 TIMES STRONGER THAN THAT OF EARTH. IT DOES NOT HAVE AURORA LIKE JUPITER AND SATURN AS IT IS FURTHER FROM THE SUN. URANUS HAS SOME NARROW RINGS – PROBABLY ROCKY COMPOSITION. NEPTUNE NEPTUNE IS SLIGHTLY SMALLER IN DIAMETER THAN URANUS, BUT HAS SLIGHTLY GREATER MASS. DISTANCE FROM SUN = 30 AU ROTATION = 16 HOURS ORBIT = 165 YEARS NEPTUNE IS THOUGHT TO HAVE A ROCKY CORE ABOUT 15 TIMES AS MASSIVE AS EARTH. TILT ON AXIS = 50 degrees NEPTUNE HAS A MAGNETIC FIELD SLIGHTLY LESS THAN THAT OF URANUS. NEPTUNE HAS FAINT RINGS. IT HAS 2 LARGE MOONS AND 6 SMALLER ONES. THE LARGEST IS TRITON AND IS ABOUT THE SAME SIZE AS OUR OWN MOON. TRITON HAS A THIN ATMOSPHERE OF MOSTLY NITROGEN AND POLAR ICE CAPS – ALSO NITROGEN. PLUTO PLUTO IS 2/3 THE SIZE OF OUR OWN MOON AND 1,200 TIMES FURTHER AWAY. THIS MAKES IT VERY DIFFICULT TO SEE, EVEN WITH A TELESCOPE. DISTANCE FROM SUN = 40 AU ROTATION = 6 ½ DAYS ORBIT = 248 YEARS PLUTO’S ORBIT PLANET MERCURY VENUS DISTANCE FROM SUN 0.39 0.72 EARTH MARS JUPITER 1 1.5 5.2 SATURN URANUS NEPTUNE PLUTO 9.5 19.2 30 40