1. The Solar System By Gina Wike

2. Solar System Early Greeks thought that everything centered around the Earth. Copernicus thought differently. He said the moon revolved around the earth and the Earth revolved around the sun. He believed the orbit was circular. His ideas were the birth of modern astronomy.

3. Solar system Galileo found evidence that supported Copernicus’ ideas. Copernicus Galileo

4. Kepler & Planetary Motion Kepler developed a sun- centered model of the solar system in which the planets orbited the sun in an elliptical shape. The sun is offset from the center. The planets travel at different speeds in their orbits around the sun. The planets closer to the sun travel faster than the planets further away from the sun.

5. Solar System The sun contains 99.86% of the mass in the solar system. Everything revolves around the sun because of its great gravitational pull. The sun and solar system formed from a cloud of gas and dust more than 4.6 billion years ago. The theory for the formation of the solar system is the solar nebula theory.

6. Solar System The inner planets formed from heavy elements. For this reason they are rocky. Rocky planets are terrestrial planets. The outer planets formed from the lighter elements. They are gaseous. The outer planets are known as the gas giants.

7. Solar System Inner planets in order- Mercury, Venus, Earth, Mars Mercury Venus Earth Mars

8. Mercury Characteristics of Mercury: 1st planet from sun has many craters like the moon thin atmosphere great extremes in temperature 450 degrees C in day and -170 degrees C at night

9. Venus 2nd planet from the sun atmosphere mostly carbon dioxide dense clouds which contain sulfuric acid clouds so dense that only 2% of sunlight strikes the surface 90 times the pressure of Earth carbon dioxide is a greenhouse gas so greenhouse effect phases like the moon

10. Venus Venus rotates in the opposite direction as Earth. This is known as retrograde rotation. It takes longer to rotate once on its axis than to revolve around the sun, so its day is longer than its year.

11. Earth 3rd planet from the sun water exists in all three states

12. Mars 4th planet from the sun Red planet because of iron oxide in the weathered rock ice caps Olympus Mons is the largest volcano in solar system

13. Outer Planets Outer Planets in order: Jupiter, Saturn, Uranus, Neptune, Pluto Outer planets contain mostly hydrogen and helium

14. Jupiter 5th planet largest planet The Great Red Spot- large storm 3 to 4 times the size of Earth Lightning many moons

15. Saturn 6th planet ringed planet second largest planet least dense planet-so low in density it would float on water

16. Uranus 7th planet Axis of rotation causes planet to lay on its side methane gas gives it a blue-green color

17. Neptune 8th planet blue-green color b/c of methane gas Great Dark Spot

18. Pluto 9th planet different from all the outer planets- it’s rocky like the inner planets

19. Comets A comet is composed of dust and rock particles mixed with frozen water, methane and ammonia

20. Comets The Oort Cloud is a collection of comets that lies just outside the solar system. The sun’s gravity pulls the comets from the Oort cloud or escapes the solar system.

21. Comets The structure of a comet is like a large, dirty snowball. As the comet travels its path around the sun, the sun vaporizes it. The vaporized gases form a bright cloud called a coma around the nucleus

22. Comets Solar winds cause the tail of a comet to point away from the sun. After many trips around the sun, most of the comet has been vaporized and the only thing left is small particles which spread out in the orbit of the comet. These small pieces of rock are called meteoroids.

23. Meteoroids, Meteors, & Meteorites A meteoroid that burns up in the atmosphere is called a meteor. Meteors are referred to as “shooting stars.” A meteor shower occurs when we pass through the path of a comet and many pieces of rock burn up in the atmosphere.

24. Meteoroids, Meteors, & Meteorites If a meteoroid is large enough, it will not burn up in the earth’s atmosphere. When it strikes Earth it is a meteorite.

25. Meteoroids, Meteors, & Meteorites Because meteorites come from comets or asteroids, scientists believe they are made of material that formed in the beginning of the solar system.

26. Asteroids An asteroid is a piece of rock that is similar to the material that formed the planets.

27. Asteroids Most asteroids are located in the area between Mars and Jupiter. This is known as the asteroid belt.