Inner Planets 1st Planet 2nd Planet 3rd Planet 4th Planet Name/Class: Date: 1st Planet 2nd Planet 3rd Planet 4th Planet

Inner Planets Surface & Atmosphere Mercury: Smallest Planet in Solar System Surface & Atmosphere Flat plains and craters. Looks similar to Luna (Earth’s moon). Craters formed early in solar system’s history. Because no water or atmosphere, the craters have not worn away over time. No atmosphere means extreme temps. Surface facing sun: day = 430C; night = -170C.

Inner Planets Exploring Mercury Mercury Much of our data comes from two space probes: Mariner 10 space probe flew around Mercury three times between 1974 – 1975. Mercury MESSENGER has passed Mercury several times and began orbiting it in 2011.

Inner Planets Surface & Atmosphere Venus = Hottest Planet in Solar System Surface & Atmosphere Flat plains covered by lava flows. More than 10,000 volcanoes. Thick atmosphere of CO2 with heavy clouds of sulfuric acid. Human would be crushed by atmosphere = 90 times greater than Earth’s pressure Hottest planet because atmosphere holds in the heat—Greenhouse effect. Similar size and mass as Earth.

Inner Planets Rotation Venus = Reverse Rotation Rotates CCW—different from most other planets and moons. Unusual rotation possible cause = large object struck it billions of years ago.

Inner Planets Exploring Venus Venus = Earth’s Twin Venera 7 = 1970 Magellan = 1990 Venus Express = 2004 & 2005has helped scientists understand how Venus’s clouds form and change.