1. Mercury: Mean Distance from Sun 57,909,175 km (35,983.1 miles) or 0.387 astronomical units Diameter 4,879.4 km (3,031.92 miles) Volume (Earth = 1) 0.054 Mass 3.3 x 10 23 kg (0.012 x 10 27 ounces) or 0.055 (Earth = 1) Density 5.43 gm/cm 3 Surface gravity 0.376 (Earth = 1) Rotation period (length of day in Earth days) 58.65 Revolution period (length of year in Earth days) 87.97 Mean surface temperature 116.86 C (332.33° F) Natural satellites None

2. Missions to Venus... Venus: Mean Distance from Sun 108,208,930 km. (6.72 x 10 7 miles) or 0.723 astronomical units Diameter 12,103.6 km (7,520.83) miles Volume (Earth = 1) 0.88 Mass 4.87 x 10 24 kg (0.17 x 10 27 ounces) or 0.814 (Earth = 1) Density 5.24 gm/cm 3 Surface gravity 0.903 (Earth = 1) Rotation period (length of day in Earth days) 243 Earth days (spins backwards compared to most other planets) Revolution period (length of year in Earth days) 224.7 Earth days Mean surface temperature 456.85 C (854.33° F) Natural satellites None

3. Venus has few craters indicating relatively young surfaces. Its atmosphere is composed mostly of carbon dioxide. There are several layers of clouds many kilometers thick composed of sulfuric acid. These clouds completely obscure our view of the surface. This dense atmosphere produces a run-away greenhouse effect that raises Venus' surface temperature by about 400 degrees to over 740 K (hot enough to melt lead).

4. MarsEarth Average Distance from Sun 142 million miles93 million miles Average Speed in Orbiting Sun 14.5 miles per second18.5 miles per second Diameter4,220 miles7,926 miles Tilt of Axis25 degrees23.5 degrees Length of Year687 Earth Days365.25 Days Length of Day24 hours 37 minutes23 hours 56 minutes Gravity.375 that of Earth2.66 times that of Mars TemperatureAverage -81 degrees FAverage 57 degrees F Atmospheremostly carbon dioxide some water vapor nitrogen, oxygen, argon, others # of Moons21

5. Evidence for Large Water Flows on Mars Layered Sedimentary Rock Possible water Channels

6. Mean Distance from Sun 778,412,010 km (4.84 x 10 8 miles) or 5.20 astronomical units Diameter 142,984 km (88,846.1 miles) Volume (Earth = 1) 1,316 Mass 1.90 x 10 27 (66.97 x 10 27 ounces) or 317.8 (Earth = 1) Density 1.33 gm/cm 3 Surface gravity 2.34 (Earth = 1) Rotation period (length of day in Earth days) 0.41 Earth day (9.8 Earth hours) Revolution period (length of year) 11.86 Earth years Mean surface temperature 14.85 - 19.85 C (58.73 - 67.73° F) Natural satellites Four largest are Ganymede, Callisto, Io, Europa. Two of next largest are Amalthea and Himalia. Twenty-two others had been discovered before 2001. Jupiter

7. Io Orbit: 422,000 km from Jupiter (5.9 R J ) Diameter: 3630 km Voyager 1 discoveries hundreds of volcanic calderas, many are still active. First real proof that the interiors of other "terrestrial" bodies are actually hot and active. The material erupting from Io's vents appears to be some form of sulfur or sulfur dioxide.

8. Voyager 1

9. Io’s Interior: Mantle of Rock, with Metallic Core

10. Distance from Jupiter: 671,000 km 9.3 R J Radius: 1,565 km Europa Europa has almost a complete absence of craters as well as almost no vertical relief. Major Atmospheric Constituent: Oxygen

11. A warm, convecting ice layer, located several kilometers below a cold, brittle surface ice crust (top model), or a layer of liquid water with a possible depth of more than 100 kilometers (bottom model). These artist's drawings depict two proposed models of the subsurface structure of Europa, If a 100 kilometer (60 mile) deep ocean existed below a 15 kilometer (10 mile) thick Europan ice crust, it would be 10 times deeper than any ocean on Earth and would contain twice as much water as Earth's oceans and rivers combined. Major salt would be magnesium sulfate while the Earth's oceans are salty due to sodium chloride (common salt).

12. Europa has an atmosphere From Plasma Sputtering

13. Distance from Jupiter: 1,070,000 km 14.95 R J Radius: 2,634 km Ganymede Ganymede is most likely composed of a rocky core with a water/ice mantle and a crust of rock and ice. Major Atmospheric Constituent: Oxygen It is heavily cratered, especially in the dark regions, implying ancient origin.

14. Ganymede Interior : Rock/Ice Crust Water/Ice mantle Rock Outer Core Metallic Core

15. Ganymede: Plasma Wind Erosion/ Mid-Latitude Projection via Global Magnetic Field

16. Distance from Jupiter: 1,883,000 km 26.3 R J Radius: 2,403 km Callisto It orbits just beyond Jupiter's main radiation belt. Major Atmospheric Constituent: Carbon Dioxide Callisto is the most heavily cratered satellite in the solar system. Its crust is very ancient and dates back 4 billion years, just shortly after the solar system was formed.

17. Callisto’s Interior : a relatively uniform mixture of comparable amounts of ice and rock.

18. Mean Distance from Sun 1,426,725,400 km (8.87 x 10 8 miles) or 9.54 astronomical units Diameter 120,536 km (74,897.6 miles) Volume (Earth = 1) 755 Mass 5.69 x 10 26 kg (2.01 x 10 28 ounces) or 95.2 (Earth = 1) Density 0.70 gm/cm 3 Surface gravity (896 cm/s (2)) 1.16 (Earth = 1) Rotation period (length of day in Earth days) 0.44 (10.2 Earth hours) Revolution period (length of year) 29.46 Earth years Mean surface temperature -139.15 C (-218.47° F) Natural satellites Titan is the largest, and the next six in size are Rhea, Iapetus, Dione, Tethys, Enceladus, Mimas. Twenty-three others had been discovered before 2001. Saturn

19. Like Jupiter, Saturn is about 75% hydrogen and 25% helium with traces of water, methane, ammonia and "rock", similar to the composition of the primordial solar system Both planets also generate more energy than they absorb from the Sun – Brown Dwarfs The rings are actually composed of innumerable small particles, ranging in size from a centimeter or so to several meters. A few kilometer-sized objects are also likely. Saturn's rings are extraordinarily thin: though they're 250,000 km or more in diameter they're less than one kilometer thick.

20. Titan Distance from Saturn: 1,221,830 km, 10 R S Radius: 2,575 km An impenetrable layer of atmosphere and clouds. Liquid seas or pools of methane or ethane; water would be frozen due to Titan's low surface temperature.

21. Kuiper Belt is a disk-shaped region past the orbit of Neptune roughly 30 to 100 AU from the Sun containing many small icy bodies. It is now considered to be the source of the short-period comets.

22. Mean Distance from Sun 2,870,972,200 km (1.78 x 10 9 miles) or 19.19 astronomical units Diameter 51,118 km (31,763.3 miles) Volume (Earth = 1) 52 Mass 8.68 x 10 25 kg (3.06 x 10 27 ounces) or 14.48 (Earth = 1) Density 1.30 gm/cm 3 Surface gravity 1.15 (Earth = 1) Rotation period (length of day in Earth hours) 0.72 or 17.9 Earth hours (spins backwards compared to most other planets) Revolution period (length of year in Earth years) 83.75 Mean surface temperature -197.15 C (-322.87° F) Natural satellites Five of largest are Miranda, Titania, Oberon, Umbriel, Ariel. Sixteen others had been discovered before 2001. Uranus

23. Mean Distance from Sun 4,498,252,900 km (2.80 x 10 9 miles) or 30.07 astronomical units Diameter 55,528 km (34,503.5 miles) Volume (Earth = 1) 44 Mass 1.02 x 10 26 kg (3.61 x 10 27 ounces) or 17.2 (Earth = 1) Density 1.76 gm/cm 3 Surface gravity tba (1100 cm/s (2) 1.19 (Earth = 1) Rotation period (length of day in Earth days) 0.67 (19.1 Earth hours) Revolution period (length of year) 163.72 Earth years Mean surface temperature tba -200.15 C (-328.27° F) Natural satellites Naiad, Thalassa, Despina, Galatea, Larissa, Proteus, Triton, Nereid Neptune

24. Mean Distance from Sun 5,906,376,200 km (3.67 x 10 9 miles) or 39.48 astronomical units Diameter 2,390 km (1,485.08 miles) Volume (Earth = 1) 0.005 Mass 1.29 x 10 22 kg (0.00046 x 10 27 ounces) or 0.0025 (Earth = 1) Density 1.1 gm/cm 3 Surface gravity 0.066 (Earth = 1) Rotation period (length of day in Earth days) 6.39 (spins backwards compared to most other planets) Revolution period (length of year) 248 Earth Years Mean surface temperature -215.35 C (-355.63° F) Natural satellites Charon Pluto