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Chapter 5 Earth and Its Moon

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  1. Chapter 5 Earth and Its Moon

  2. Chapter 5Earth and Its Moon

  3. Tatoonie

  4. Units of Chapter 5 Earth and the Moon in Bulk The Tides Atmospheres Interiors Surface Activity on Earth The Surface of the Moon Magnetospheres History of the Earth–Moon System

  5. Question 1 a) an atmosphere. b) a hydrosphere. c) a magnetosphere. d) It lacks all of the above. The Moon’s internal structure is similar to Earth’s, but the Moon lacks

  6. Question 1 a) an atmosphere. b) a hydrosphere. c) a magnetosphere. d) It lacks all of the above. The Moon’s internal structure is similar to Earth’s, but the Moon lacks Both the Earth and Moon have a core, mantle, and crust, but the Earth has a liquid water-rich layer, air, and a magnetic field.

  7. Earth and the Moon in Bulk

  8. The Tides Tidesare due to gravitational force on Earth from Moon – force on near side of Earth is greater than force on far side. Water can flow freely in response.

  9. The Tides The Sun has less effect, but it does modify the lunar tides.

  10. Question 2 a) new moon b) waxing crescent moon c) full moon d) third quarter moon e) both new and full moon At what lunar phase would the variation between high & low tides be greatest?

  11. Question 2 a) new moon b) waxing crescent moon c) full moon d) third quarter moon e) both new and full moon At what lunar phase would the variation between high & low tides be greatest? At new and full moon phases, the Sun and Moon combine to stretch the Earth and its oceans even more.We see higher high tides and lower low tides.

  12. The Tides Tides tend to exert a “drag” force on Earth, slowing its rotation. This will continue until Earth rotates synchronously with the Moon, so that the same side of Earth always points toward the Moon.

  13. The Tides This has already happened with the Moon, whose near side is always toward Earth.

  14. Question 3 a) the Sun’s gravity b) Earth’s magnetic field c) Earth’s tidal force d) the solar wind e) the Moon’s magnetic field What force riveted the Moon’s near side to constantly face Earth?

  15. Question 3 a) the Sun’s gravity b) Earth’s magnetic field c) Earth’s tidal force d) the solar wind e) the Moon’s magnetic field What force rivets the Moon’s near side to constantly face Earth? Just as the Moon creates tides on Earth with its gravitational force, the Earth affects the Moon, too. Because of Earth’s tidal force, the Moon spins once a month.

  16. Atmospheres • The blue curve shows the temperature at each altitude. • Troposphere is where convection takes place – responsible for weather.

  17. Atmospheres Convection depends on warming of ground by the Sun.

  18. Atmospheres Ionosphere is ionized by solar radiation, and is a good conductor. Reflects radio waves in the AM range, but transparent to FM and TV. Ozone layer is in the stratosphere and absorbs ultraviolet radiation.

  19. Earth’s Growing Ozone Hole Chlorofluorocarbons (CFCs) have been damaging the ozone layer, resulting in ozone hole. 1 chlorine atom can destroy up to a 100,000 ozone molecules. It will be decades before the hole will go away.

  20. Question 4 A planetary atmosphere with ozone could protect surface dwellers from a) ultraviolet radiation. b) charged particles in the solar wind. c) meteor impacts. d) optical radiation. e) radar waves.

  21. Ozone in the stratosphere (about 30-50 km high) absorbs UV light, and heats the upper atmosphere. Question 4 A planetary atmosphere with ozone could protect surface dwellers from a) ultraviolet radiation. b) charged particles in the solar wind. c) meteor impacts. d) optical radiation. e) radar waves.

  22. Atmospheres • Surface heating: • Sunlight that is not reflected is absorbed by Earth’s surface, warming it. • Surface re-radiates as infrared thermal radiation. • Atmosphere absorbs some infrared, causing further heating.

  23. Atmospheres This is known as the greenhouse effect.

  24. Question 5 The principal greenhouse gases in our present atmosphere are a) hydrogen and helium. b) oxygen and nitrogen. c) water vapor and carbon dioxide. d) methane and ammonia. e) sulfuric acid vapor and CO2.

  25. Question 5 The principal greenhouse gases in our present atmosphere are a) hydrogen and helium. b) oxygen and nitrogen. c) water vapor and carbon dioxide. d) methane and ammonia. e) sulfuric acid vapor and CO2. A greenhouse gas lets shorter- wavelength light pass through, but absorbs longer-wavelength light.

  26. The Greenhouse Effect and Global Warming There is extremely strong evidence that Earth is getting warmer. The cause of this warming is a subject of intense debate; many scientists believe it is related to the corresponding increase in atmospheric carbon dioxide.

  27. Greenhouse Effect • Some greenhouse gas is necessary. Without a trace of GHG Earth would be -19 C instead of +14 C. • Too much GHG and Earth gets too hot. • GHG such as water vapor, CO2 and Methane.

  28. Question 6 a) we would not have to worry about ecological problems. b) the Earth’s oceans would be frozen. c) the amount of nitrogen & oxygen would be much less. d) the icecaps would have melted. e) global warming would still occur. Without the greenhouse effect in our atmosphere

  29. Question 6 a) we would not have to worry about ecological problems. b) the Earth’s oceans would be frozen. c) the amount of nitrogen & oxygen would be much less. d) the icecaps would have melted. e) global warming would still occur. Without the greenhouse effect in our atmosphere Earth’s greenhouse effect makes the planet about 40° C hotter than it would otherwise be. This raises the average surface temperature above the freezing point of water.

  30. Interiors • Seismic waves: • Earthquakes produce both pressure and shear waves. • Pressure waves will travel through both liquids and solids. • Shear waves will not travel through liquids, as liquids do not resist shear forces. • Wave speed depends on density of material.

  31. Interiors The pressure wave is a longitudinal wave, whereas the shear wave is a transverse wave. A shear wave cannot propagate within a liquid.

  32. P - wave

  33. S - Wave

  34. Interiors Can use pattern of reflections during earthquakes to deduce interior structure of Earth.

  35. Interiors Currently accepted model

  36. Interiors Mantle is much less dense than core. Mantle is rocky; core is metallic, consisting of iron and nickel. Outer core is liquid; inner core is solid, due to pressure. Volcanic lava comes from mantle, allows analysis of composition.

  37. Surface Activity on Earth Continental drift: Earth’s entire surface is covered with crustal plates, which can move independently. At plate boundaries, earthquakes and volcanoes can occur. Volcano earthquake Plate line Drift Direction

  38. San Andreas Fault 2 inches per year 21 feet in 1906 quake

  39. Surface Activity on Earth Plates moving away from each other create rifts.

  40. 5.5 Surface Activity on Earth If we follow the continental drift backward, the continents merge into one, called Pangaea.

  41. The Surface of the Moon The Moon has large dark flat areas, due to lava flow, called maria (early observers thought they were oceans).

  42. The Surface of the Moon The far side of the Moon is relatively unmarked.

  43. Question 7 a) uniformly all over the Moon. b) mostly on the side facing Earth. c) mostly on the far side of the Moon. d) only in the dark areas, out of sunlight. e) in the highlands, among mountains. Lunar maria are found

  44. Question 7 a) uniformly all over the Moon. b) mostly on the side facing Earth. c) mostly on the far side of the Moon. d) only in the dark areas, out of sunlight. e) in the highlands, among mountains. Lunar maria are found Because the Moon keeps its near side always facing Earth, that side has a thinner crust, and is also less cratered.

  45. The Surface of the Moon Crater formation: Meteoroid strikes the Moon, ejecting material; explosion ejects more material, leaving a crater.

  46. The Surface of the Moon • Craters are typically about 10 times as wide as the meteoroid creating them, and twice as deep. • Rock is pulverized to a much greater depth. • Most lunar craters date to at least 3.9 billion years ago; much less bombardment since then.