The Solar System

1. The Solar System

2. The Inner Planets • The inner planets are the 4 planets closest to the sun: • Mercury • Venus • Earth • Mars • The four inner planets are small and dense and have rocky surfaces.

3. Mercury • Mercury is the smallest terrestrial planet and the planet closest to the sun. • Mercury’s diameter is about 3,000 miles. • Mercury’s distance from the sun is about 36 million miles. • Mercury’s revolution around the sun takes about 88 days. • Mercury’s rotation on its axis takes about 59days.

4. Mercury • Mercury has flat plains and craters on its surface. • Mercury has no atmosphere. • Mercury is a planet of extremes, with greater temperature ranges than any other planet in the solar system.

5. Mercury • It is so close to the sun that during the day , the side facing the sun reaches temperatures of 806 degrees F. • At night, because Mercury has no atmosphere it drops to as low as -274 degrees F. • Mercury has no moons or rings.

6. Venus • Venus is similar in size and mass to Earth. It is sometimes called Earth’s twin. • Venus’s diameter is about 7,500 miles. • Venus’s distance from the sun is about 67 million miles. • Venus is covered with rock and has many volcanoes, plains, and lava flows. • Revolution around the sun: 7 Earth months (about 210 days) . • Rotation: 243 days • It rotates so slowly, its day is longer than its year!

7. Venus • Venus rotates east to west, the opposite direction of most other planets. • Venus’s atmosphere is so thick that it is always cloudy there. • From Earth, astronomers can view a large cloud. • The clouds are made up mostly of droplets of sulfuric acid.

8. Venus • If you could stand on Venus’s surface, you would quickly be crushed by the weight of its atmosphere. • The atmosphere is 90 times greater than the Earth’s atmosphere. • You could not breathe on Venus because its atmosphere is mostly carbon dioxide.

9. Venus • Many probes have visited Venus to gather information. The first probe landed on Venus in 1970. • Venus has no moons or rings.

10. Earth • Earth is the only planet to have liquid water at its surface. • 70% of Earth’s surface is by water. • Earth has a suitable temperature range to have water as a solid, liquid, and gas. • Earth has enough gravity to hold on to the gases. These gases make up Earth’s atmosphere.

11. Earth • Earth has an atmosphere that is rich in oxygen. • The Earth’s atmosphere is about 21%oxygen and 78% nitrogen. • Earth’s revolution around the sun takes about 365 ¼ days. • Earth’s rotation on its axis takes about 24 hours.

12. Earth • Earth is about 94 million miles away from the sun. • Earth’s diameter is about 8,000 miles. • Earth has 1 moon and no rings.

13. Mars • Mars is called the red planet. • Mars has a reddish color due to the iron –rich rocks that cover most of its surface. • Mars has an atmosphere that is 95% carbon dioxide.

14. Mars • We can view Mars from Earth with a telescope because it has a thin atmosphere with a few clouds. • Temperatures on Mars range from -220 F to 20 degrees F. • The revolution of Mars around the sun takes about 687 days.

15. Mars • The rotation of Mars on its axis takes about 24 hours and 39 minutes. • The diameter of Mars is about 4,221 miles. • Mars is approximately 141 million miles from the sun. • Some regions of Mars has volcanoes. Mars contains the largest inactive volcano in the solar system: Olympus Mons.

16. Mars • Scientists believe the a large amount of water once flowed on Mars. • At present, liquid water cannot exist on Mars because its thin atmosphere would cause evaporation to occur. • The water that once existed is now frozen in polar ice caps with carbon dioxide and small amounts of water vapor.

17. Mars has a tilted axis similar to the Earth; therefore, scientists believe it has seasons similar to Earth. Mars has 2 moons and no rings.