Powerpoint Presentation Earth: An Introduction to Physical Geology, 7e

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Powerpoint PresentationEarth An Introduction to
Physical Geology, 7e

• Tarbuck Lutgens

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Planetary GeologyEarth, 7e - Chapter 22

• Stan Hatfield and Ken Pinzke
• Southwestern Illinois College

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The planets An overview

• The solar system includes
• Sun
• Nine planets and their satellites
• Asteroids
• Comets
• Meteoroids

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The planets An overview

• A planet's orbit lies in an orbital plane
• Similar to a flat sheet of paper
• The orbital planes of the planets are inclined
• Orbital planes of seven planets lie within 3
  degrees of the Sun's equator

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Orbits of the planets
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The planets An overview

• Two groups of planets occur in the solar system
• Terrestrial (Earthlike) planets
• Small, dense, rocky planets of Mercury, Venus,
  Earth, and Mars
• Jovian (Jupiter-like) planets
• Large, low density, gaseous planets of Jupiter,
  Saturn, Uranus, and Neptune
• Pluto is not included in either group

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The planets An overview

• Planets are composed of
• Gases mainly hydrogen and helium
• Rocks silicate minerals and metallic iron
• Ices ammonia, methane, carbon dioxide, and
  water

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Origin and evolution of the planets

• Nebular hypothesis
• Planets formed about 5 billion years ago
• Solar system condensed from a gaseous nebula
• As the planets formed, the material that compose
  them separated
• Process is called chemical differentiation

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Origin and evolution of the planets

• Due to their surface gravitations, Venus and
  Earth retained atmospheric gases
• Due to frigid temperatures, the Jovian planets
  contain a high percentage of ices

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Earths moon

• General characteristics
• Diameter of 2150 miles is unusually large
  compared to its parent planet
• Density about three times that of water
• Gravity one-sixth of Earths

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Earths moon

• Lunar surface
• Maria darker lowlands covered by basaltic lava
  flows
• Highlands brighter more densely cratered
  regions
• Craters are produced by meteoroid impacts

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Major topographic features on the lunar surface
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Formation of lunar maria
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Earths moon

• Lunar History
• Most widely accepted hypothesis suggests that a
  giant asteroid collided with Earth to produce the
  moon
• One method used to work out lunar history is to
  observe crater density
• Older areas have a higher density
• Younger areas are still smooth

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Earths moon

• Lunar History
• Moon evolved in three phases
• Original crust (highlands) around 4.5 billion
  years old (same age as Earth)
• Formation of maria basins between 3.2 and 3.8
  billion years ago
• Formation of rayed craters (ejected material from
  craters is still visible)

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The planets a brief tour

• Mercury the innermost planet
• Second smallest
• No atmosphere
• Cratered highlands
• Vast, smooth terrains that resemble maria
• Very dense
• Revolves quickly and rotates slowly

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The planets a brief tour

• Venus the veiled planet
• Second to the moon in brilliance
• Similar to Earth in size, density, mass, and
  location in the solar system
• Shrouded in thick clouds of carbon dioxide
• Surface mapped by radar is mainly subdued plains
  covered by volcanic flows

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Mons Olympus a large, inactive shield volcano
on Mars
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The planets a brief tour

• Mars the red planet
• Atmosphere of carbon dioxide is only 1 percent as
  dense as Earths
• Surface of numerous large volcanoes and canyons
• Tectonically dead
• Stream drainage pattern found in some areas

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The planets a brief tour

• Jupiter lord of the heavens
• Largest planet
• Rapid rotation less than 10 hours
• Banded appearance due to winds
• Great Red Spot is a cyclonic storm
• Surface is thought to be a vast ocean of liquid
  hydrogen
• At least 16 moons

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The planets a brief tour

• Saturn the elegant planet
• Similar to Jupiter in atmosphere, composition,
  and internal structure
• Most prominent feature are an extensive system of
  rings
• Multiple moons Titan is second largest in the
  solar system
• Dynamic atmosphere with cyclonic storms

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The ring system of Saturn
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The planets a brief tour

• Uranus
• Uranus and Neptune are considered twin planets
• Rotates on its side
• System of rings
• Large moons with quite varied terrains

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The planets a brief tour

• Neptune
• Dynamic atmosphere one of the windiest places
  in the solar system
• Eight satellites
• Triton, the largest of Neptunes moons, exhibits
  retrograde motion, lowest surface temperatures in
  the solar system, and volcanic-like activity

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The planets a brief tour

• Pluto
• Too dim to be visible with the unaided eye
• Discovered in 1930
• Highly elongated orbit causes it to occasionally
  travel inside the orbit of Neptune

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Minor members of the solar system

• Asteroids microplanets
• Most lie between Mars and Jupiter
• Small bodies largest (Ceres) is about 620 miles
  in diameter
• Some have very eccentric orbits
• Many of the recent impacts on the Earth and Moon
  were asteroids
• Origin is uncertain

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The asteroid belt
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Minor members of the solar system

• Comets dirty snowballs
• Composition of frozen gases with some rocky and
  metallic materials
• Frozen gases vaporize to produce a glowing head
  when the comet is near the Sun
• Origin is not well known
• Most famous short-period comet is Halleys comet

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Minor members of the solar system

• Meteoroids
• Called meteors when they enter Earths atmosphere
• Referred to meteorites when they are found on
  Earth
• Classified by composition irons, stony,
  stony-irons, and carbonaceous chondrites
• Give an idea as to the age of the solar system

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End of Chapter 22