The Inner planets

1. The Inner planets Section 28.2

2. Main idea • Mercury, Venus, and Earth, and Mars have high densities and rocky surfaces • This is why we call them the terrestrial planets

3. mercury • Closest to the Sun making it difficult to see from Earth • 1/3 the size of Earth • Has no moons • Atmosphere is replenished by the Sun • Atmosphere composed of oxygen and sodium • Surface covered with craters and plains

4. Scarps: planetwide system of cliffs

6. Venus • 2nd closest to the Sun • Has no moons • The brightest planet in the sky • Often called the evening star

7. Rotates very slowly • 1 day on Venus = 243 Earth days • Venus rotates clockwise (opposite to most) • Very similar to Earth in diameter, mass, and density • Clouds on Venus consist of sulfuric acid • Greenhouse effect causes the high concentration carbon dioxide in the atmosphere to keep Venus’ surface temperature hot enough to melt lead. • Venus is the hottest planet

8. Earth

9. It’s distance from the Sun and nearly circular orbit are perfect for life which allow water to exist in all three states • It’s mild greenhouse effect and moderately dense atmosphere of Nitrogen and Oxygen are also perfect conditions for life • Most tectonically active terrestrial planet • Has one moon

10. Mars • Called the ‘red planet’ because of its reddish surface • Smaller than Earth and less dense • Has two moons: Phobos and Deimos • Thin atmosphere • Constant wind and dust storms

11. Surface • Northern hemisphere: cratered plains • Southern hemisphere: cratered highlands • Four gigantic volcanoes near equator • Largest: Olympus Mons • Ice caps on both poles

12. Tectonics • VallesMarineris: 10 times the length of the Grand Canyon • There is currently NO plate movement. The volcanoes and canyons were caused by hot spots of volcanic activity • Erosion patterns suggest that water once existed on Mars

13. Mars curiosity