1. Terrestrial Planets- Mercury & Venus THE SOLAR SYSTEM

2. PLANETS All planets travel around the sun Some move faster than others Revolution-the time it takes for a planet to complete one orbit around the sun

3. PLANETS Planets also spin around an imaginary center line called the axis Rotation-the time takes for a planet to complete one spin on its axis Some planets are tilted on their axis

4. MERCURY Stats: 0.39 AU from the sun Rotation period: 1,407 hours (58 days) Revolution period: 88 days Axis tilt 0˚ Highest surface temperature: 427˚C Lowest surface temperature: -184˚C Gravity: 38% of Earth’s Diameter: 4,879 km

5. MERCURY Has the shortest orbit time of any planet Has the most elliptical orbit of any planet Planet is made of about 70% metallic and 30% silicate minerals

6. MERCURY Least understood of all the planets Only 2 missions have gone to Mercury Mariner 10 (1973) MESSENGER (2004)

7. MERCURY Mariner Program Designed to gather data about the inner planets-Mercury, Venus and Mars Only the Mariner 10 probe went to Mercury Launched in November, 1973 Flew past Mercury 3 times

9. MERCURY Mariner Program Mapped about 45% of Mercury’s surface First close pictures of surface Also studied the magnetic field around Mercury

10. MERCURY MESSENGER Program Launched in August, 2004 Entered Mercury’s orbit in March, 2011 Data is still being collected and analyzed

11. VENUS Stats: 0.72 AU from the sun Rotation period: 5,832 hours (243 days) Revolution period: 225 days Axis tilt 177˚ Average surface temperature: 465˚C Gravity: 89% of Earth’s Diameter: 12,104 km

12. VENUS Similar size and mass of Earth Has a Retrograde rotation Clockwise spin of a planet from the north pole Also has the slowest rotation of all planets

13. VENUS Venus is surrounded by thick clouds Only 10% of sunlight reaches the surface Cannot see the surface through the clouds Atmosphere is extremely dense Made of 96.5% CO 2 and 3.5% N 2 Pressure is 93 times that of Earth Rains sulfuric acid

14. VENUS Surface was mapped by the Magellan probe 80% of the surface is smooth, flat plains 20% of surface form two, raised continents 167 large volcanoes on the surface Features are very well preserved No tectonic plates Entire surface is recycled every 300-600 million years

15. VENUS Thousands of impact craters Between 3 and 280km in diameter Objects causing craters less than 3km burn up in atmosphere before impact

16. VENUS Many different missions from the USA and Russia went to explore Venus RussianAmericanOther Venera (1961-1984)Mariner 1-10 (1962-1973)Venus Express-ESA Vega (1986)Pioneer (1960, 1978)Akatsuki-JAXA Magellan (1989-1991) MESSENGER (2004- present)

17. VENUS Venera Project-16 missions, 10 successful landings First probes to safely land on another planet First to return images of another planet’s surface First to map the surface of Venus Probes lasted between 23 min and 2 hours on surface

19. VENUS Mariner Project-10 missions, 7 successful First planetary flyby First planetary orbiter First use of gravity assist maneuver Using gravity of a planet to accelerate a spacecraft

21. VENUS

22. VENUS