1. What is a planet made of?

2. One way in which scientists look at what a planet is made of is by looking at density

3. Let’s look at the density of the Planets PlanetDensity (gm/cm 3 ) Mercury5.44 Venus5.2 Earth5.52 Mars3.93 Jupiter1.3 Saturn0.69 Uranus1.28 Neptune1.64 Pluto2.06

4. Let’s look at the density of the Planets PlanetDensity (gm/cm 3 ) Mercury5.44 Venus5.2 Earth5.52 Mars3.93 Jupiter1.3 Saturn0.69 Uranus1.28 Neptune1.64 Pluto2.06 The first four planets have higher densities

5. Let’s look at the density of the Planets PlanetDensity (gm/cm 3 ) Mercury5.44 Venus5.2 Earth5.52 Mars3.93 Jupiter1.3 Saturn0.69 Uranus1.28 Neptune1.64 Pluto2.06 The next four planets have lower densities

6. Let’s look at the density of the Planets PlanetDensity (gm/cm 3 ) Mercury5.44 Venus5.2 Earth5.52 Mars3.93 Jupiter1.3 Saturn0.69 Uranus1.28 Neptune1.64 Pluto2.06 And Pluto is somewhere in between

7. Let’s look at the density of the Planets PlanetDensity (gm/cm 3 ) Mercury5.44 Venus5.2 Earth5.52 Mars3.93 Jupiter1.3 Saturn0.69 Uranus1.28 Neptune1.64 Pluto2.06 These planets are known as the Rocky Planets

8. Let’s look at the density of the Planets PlanetDensity (gm/cm 3 ) Mercury5.44 Venus5.2 Earth5.52 Mars3.93 Jupiter1.3 Saturn0.69 Uranus1.28 Neptune1.64 Pluto2.06 These planets are known as the Rocky Planets Because their densities suggest that they are mostly made of rock and heavier materials

9. Let’s look at the density of the Planets PlanetDensity (gm/cm 3 ) Mercury5.44 Venus5.2 Earth5.52 Mars3.93 Jupiter1.3 Saturn0.69 Uranus1.28 Neptune1.64 Pluto2.06 These Planets are known as the gaseous planets

10. Let’s look at the density of the Planets PlanetDensity (gm/cm 3 ) Mercury5.44 Venus5.2 Earth5.52 Mars3.93 Jupiter1.3 Saturn0.69 Uranus1.28 Neptune1.64 Pluto2.06 These Planets are known as the gaseous planets Because their densities suggest that they are mostly made of gas

11. Let’s look at the Earth

12. The Inside of the Earth is made of Several Layers

13. The Crust: A Thin Rock Material

14. The Inside of the Earth is made of Several Layers The Mantle: A Dense and Mostly Solid Rock Material

15. The Inside of the Earth is made of Several Layers The Outer Core: Liquid Iron and Nickel

16. The Inside of the Earth is made of Several Layers The Inner Core: Solid Iron and Nickel

17. How Do We Know This? The Outer Core: Liquid Iron and Nickel The Inner Core: Solid Iron and Nickel The Mantle: A Dense and Mostly Solid Rock Material The Crust: A Thin Rock Material

18. Density

19. The Density of Earth is 5.53 gm/cm 3

20. We know the surface of the Earth is covered with Rocks

21. The Density of Earth is 5.53 gm/cm 3 The Land is covered mostly by a type of rock called Granite ( density of Granite = 2.6 gm/cm 3 )

22. The Density of Earth is 5.53 gm/cm 3 The Ocean is mostly covered by a type of rock called Basalt ( density of Granite = 3.3 gm/cm 3 ) The Land is covered mostly by a type of rock called Granite ( density of Granite = 2.6 gm/cm 3 )

23. The Density of Earth is 5.53 gm/cm 3 Granite = 2.7 gm/cm 3 Basalt = 3.3 gm/cm 3 Neither of these Rocks is dense enough to account for the density of the Earth

24. The Density of Earth is 5.53 gm/cm 3 Granite = 2.7 gm/cm 3 Basalt = 3.3 gm/cm 3 Iron has a density of 7.9 gm/cm 3

25. The Density of Earth is 5.53 gm/cm 3 Granite = 2.7 gm/cm 3 Basalt = 3.3 gm/cm 3 Iron has a density of 7.9 gm/cm 3 So we believe the inside of the Earth is made of a heavy element such as Iron or Nickel (density of Nickel = 8.9 gm/cm 3 )

26. Density of Rocks  3 gm/cm 3 The Density of Earth is 5.53 gm/cm 3

27. Density of Rocks  3 gm/cm 3 The Density of Earth is 5.53 gm/cm 3 Density of Iron/Nickel  8 gm/cm 3

28. Density of Rocks  3 gm/cm 3 The Density of Earth is 5.53 gm/cm 3 Density of Iron/Nickel  8 gm/cm 3 So we believe about ½ the Earth is a Rock-like material and the other ½ a heavy metal such as iron and nickel The density of the Earth will be the average of the two:

29. The Density of Mars is 3.9 gm/cm 3

30. Remember the Earth has a density of 5.5 gm/cm 3 What does this tell us about the interior of Mars?

31. The Density of Mars is 3.9 gm/cm 3 Remember the Earth has a density of 5.5 gm/cm 3 What does this tell us about the interior of Mars? Mars has a much smaller Iron Core than Earth does

32. What does the density tell us about the interior of these bodies? (do they have a very big core?) Mercurydensity = 5.4 gm/cm 3 Venusdensity = 5.2 gm/cm 3 Moondensity = 3.3 gm/cm 3 Remember the Earth has a density of 5.5 gm/cm 3

33. The Density of Jupiter is 1.3 gm/cm 3 What does this tell us about the interior of Jupiter?

34. The Density of Jupiter is 1.3 gm/cm 3 What does this tell us about the interior of Jupiter? Since the density of Jupiter is so small the planet has to be made mostly of very light material

35. The Density of Jupiter is 1.3 gm/cm 3 What does this tell us about the interior of Jupiter? Since the density of Jupiter is so small the planet has to be made mostly of very light material Jupiter is made mostly of Hydrogen and Helium gas

36. The Density of Saturn is 0.69 gm/cm 3

37. Saturn is also made up mostly of Hydrogen and Helium

38. The Density of Saturn is 0.69 gm/cm 3 Saturn is also made up mostly of Hydrogen and Helium The density of Saturn is less than 1 gm/cm 3 so this planet can float in water

40. What does the density tell us about the interior of Uranus and Neptune? Uranusdensity = 1.3 gm/cm 3 Neptunedensity = 1.6 gm/cm 3

41. What does the density tell us about the interior of Uranus and Neptune? Uranusdensity = 1.3 gm/cm 3 Neptunedensity = 1.6 gm/cm 3 Like Jupiter and Saturn these planets have low densities which suggest they are primarily made of gas. (in this case methane)

42. density = 2.1 gm/cm 3 Pluto Since Pluto is so far away it is hard to see the planet. Since it is good at reflecting light scientists suspect there is ice at the surface, possibly frozen Nitrogen

43. End