2.  Small, have rocky surfaces  Terrestrial Planets: meaning earth

4.  closest to the Sun  Interior is made up of iron and nickel metals  So close to the sun that people can’t get a good view of it.  Only half of Mercury has been photographed  Many flat plains and craters

5.  Thin/No atmosphere  Gases where once heated so much they moved so fast they escaped Mercury’s atmosphere  Greatest range of temperature of all planets

6.  Nearest planet to sun  Our moon and Mercury’s surface look alike (craters)  No atmosphere  No moons  Revolves around sun with same side always facing sun  Greatest range of temperature  (662°F=day, -274°F=night)

8.  Earth’s twin (similar in size)  If you see a bright object in the west after sunset it is most likely Venus  Venus’s Rotation  Takes 7.5 Earth months to revolve around sun  8 months to rotate on axis  Day is longer than Year  Rotates east to west (clockwise) unlike most planets  Retrograde rotation: moving backward

9.  Atmosphere so thick it is always cloudy  No sunny days  If you stood on Venus you would be crushed. Atmosphere is so strong  Greenhouse Effect: trapping of heat by atmosphere

10.  19 spacecraft have visited  1 st only last 23 minutes before it was destroyed  Rocky areas, volcanoes with lava flows, craters, strange domes

11.  Second planet from sun  Spins slowly backwards as it orbits  Atmosphere made mostly of carbon dioxide  Hottest planet (860°F)  Surface: craters, mountains, volcanic lava flows.  No moons  Day is longer than year

13.  3 rd planet from the sun  70% water, 30% land  1 moon  Conditions necessary for life  Has volcanoes and earthquakes  Three layers  Crust: solid rocky surface  Mantle: hot molten rock  Core: inner solid, outer liquid

15.  Red planet: looks slightly red in the sky  You could walk on Mars but would need airtight suit and oxygen tank  Frozen ice at each pole  Has season’s just like Earth

16.  Giant volcanoes but probably not active  Red rock from rusty dust  No oceans or water now  Was water millions of years ago

17.  Has two moon’s  Phobos: 27 km in diameter (distance car travels on highway in 15 minutes  Deimos: 15 km  Covered with craters

18.  4 th planet from sun  Rust causes surface to have a red glow  Polar ice caps at each pole  Two small moons (covered in craters)  Thin atmosphere  Huge dust storms cover surface at times  Has seasons  Volcanoes  No water now  Day=25 hours  Year=686 days