2. Average-sized star that looks big because of its distance from Earth Average-sized star that looks big because of its distance from Earth Sun’s gravity holds the planets in their orbits Sun’s gravity holds the planets in their orbits Provides light, heat and other energy to Earth (inexhaustible energy source) Provides light, heat and other energy to Earth (inexhaustible energy source) Made almost entirely of gas Made almost entirely of gas Almost 838,900 miles wide (could hold more than 1 million Earths inside) Almost 838,900 miles wide (could hold more than 1 million Earths inside)

3. Sunspots-dark area on the surface of the sun because that area is cooler than the rest of the sun Solar flare-magnetic storm on the Sun which appears very bright Corona-the outermost layer of the Sun’s atmosphere

4. Sun center of the universe all planets revolve around it (one year)

5. Sun center of the universe all planets revolve around it (one year) Mercury

6. Fun Fact: In the daytime Mercury’s surface is hot enough to melt lead Length of year: 88 Earth days Moons: None Surface: Rocky with craters

7. Sun center of the universe all planets revolve around it (one year) Mercury Venus

8. Fun Fact: Venus rotates backward compared with most of the other planets Length of year: 225 Earth days Moons: None Surface: Rocky with constant cover of thick clouds

9. Sun center of the universe all planets revolve around it (one year) Mercury Venus Earth

10. Fun Fact: Only planet known to support life Length of year: 365 days Moons: One Surface: Mostly water

11. Sun center of the universe all planets revolve around it (one year) Mercury Venus Earth Mars

12. Fun Fact: Largest volcano in the Solar System, Olympus Mons. Known as the Red Planet. Length of year: Almost 2 Earth years Moons: Two Surface: Rocky with volcanoes, canyons and red dust

13. Sun center of the universe all planets revolve around it (one year) Mercury Venus Earth Mars Rocky Surface Closer to the sun Warmer Small Two moons or less

14. Sun center of the universe all planets revolve around it (one year) Mercury Venus Earth Mars Rocky Surface Closer to the sun Warmer Small Two moons or less Jupiter

15. Fun Fact: Two Earths could fit inside Jupiter’s Great Red Spot, a huge hurricane-like storm on Jupiter’s surface Length of year: About 12 Earth years Moons: 16 known Surface: No solid surface; cold, slushy gases

16. Sun center of the universe all planets revolve around it (one year) Mercury Venus Earth Mars Rocky Surface Closer to the sun Warmer Small Two moons or less Jupiter Saturn

17. Fun Fact: Saturn has a large system of rings that reaches 416,000 kilometers (260,000 miles) from its surface Length of year: About 29 Earth years Moons: 60 known Surface: Frozen gases

18. Sun center of the universe all planets revolve around it (one year) Mercury Venus Earth Mars Rocky Surface Closer to the sun Warmer Small Two moons or less Jupiter Saturn Uranus

19. Fun Fact: Uranus rolls on its side as it orbits the sun Length of year: 84 Earth years Moons: 27 known Surface: Frozen gases

20. Sun center of the universe all planets revolve around it (one year) Mercury Venus Earth Mars Rocky Surface Closer to the sun Warmer Small Two moons or less Jupiter Saturn Uranus Neptune

21. Fun Fact: Since Pluto is no longer recognized as a planet, Neptune is the farthest planet from the Sun Length of year: 165 Earth years Moons: 13 known Surface: Frozen gases

22. Sun center of the universe all planets revolve around it (one year) Mercury Venus Earth Mars Rocky Surface Closer to the sun Warmer Small Two moons or less Jupiter Saturn Uranus Neptune Made of frozen gases Farther from the sun Colder Much larger Many moons

23. Sun center of the universe all planets revolve around it (one year) Mercury Venus Earth Mars Rocky Surface Closer to the sun Warmer Small Two moons or less Jupiter Saturn Uranus Neptune Made of frozen gases Farther from the sun Colder Much larger Many moons