Earth and Other Planets

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Earth and Other Planets

• Chapter 16

Great Idea Earth, one of the planets that orbit
the Sun, formed 4.5 billion years ago from a
great cloud of dust.
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Chapter Outline

• The Formation of the Solar System
• Exploring the Solar System

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The Formation of the Solar System
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Clues to the Origin of the Solar System

• Solar system
• Objects gravitationally bound to Sun
• Deduction of origin
• Observations
• Earth
• Space

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Clue 1 Planetary Orbits

• Features of solar system
• All planets orbit in same direction
• Orbits in same plane
• Most rotate in direction of orbit

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Clue 2 Distribution of Mass

• Most material within Sun
• Two types of planets
• Terrestrial planets
• Jovian planets
• Other objects
• Moons, asteroids, comets

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The Nebular Hypothesis

• Nebular Hypothesis
• Cloud of dust and gas
• 99 H and He
• Collapse of nebula
• Planetary orbits
• Clumping of matter
• Planetesimals
• Temperature

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The surface of Venus is shrouded in clouds, but
the Magellan spacecraft produced radar images
of the surface. In this computer-generated view
of a Venusian volcano, the vertical relief has
been greatly exaggerated.
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The Formation of Earth

• Planetesimals
• Combined to form earth
• Great bombardment
• Meteors
• Growth of planet
• 20 metric tons per day

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Differentiation

• Differentiation
• Heat from collisions
• Dense material sank to center
• Lighter material rose to surface
• Structure
• Core
• Mantle
• Crust

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Researchers attain high pressures, equivalent to
those deep inside the Earth and other planets,
using the diamond anvil cell. Looking through
such diamond cells you can observe pressurized
samples such as this high-pressure ice crystal
that was formed at room temperature by squeezing
water.
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Earths Atmosphere

• The temperature of the atmosphere is a
  complicated function of altitude.

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Our Atmosphere 50 below 3.5 miles 90 below 10
miles 99 below 20 miles ozone hole global
warming
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The concentration of which gas is increasing in
our atmosphere leading to global warming?
A Clicker Question.

• water
• acetone
• carbon dioxide
• carbon monoxide
• tri-carbon

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Ozone and the Upper Atmosphere

• Ozone absorbs photons with a wavelength between
  240 and 310 nm.
• Most of the ozone is present in the stratosphere
• Between 30 and 90 km photodissociation of oxygen
  is possible
• O2(g) h? ? 2O(g)

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Ozone and the Upper Atmosphere

• The oxygen atoms can collide with oxygen
  molecules to form ozone
• O(g) O2(g) ? O3(g)

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Ozone and the Upper Atmosphere

• Depletion of the Ozone Layer
• In 1974 Rowland and Molina showed that chlorine
  from chlorofluorocarbons (CFCs) deplete the ozone
  layer by catalyzing the formation of ClO and O2.

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The Formation of the Moon

• Big Splash
• Large object impacted earth
• Parts of mantle blown into orbit
• Moon formed from this material

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Planetary Idiosyncracies

• Cratering
• Mercury, Mars, Moon
• None on earth
• weathering
• Rotation
• Venus
• Earths axis
• Uranus

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The Evolution of Planetary Atmospheres

• Earths atmosphere
• Early
• Outgassing
• Atmosphere was N2, CO2, H2, H2O
• Gravitational escape
• Living organisms

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Exploring the Solar System
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The Inner Solar System

• Mercury, Venus, Mars
• Mercury and Venus too hot for life
• Mars Exploration
• Multiple missions
• Found evidence of water

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The Outer Solar System

• Jupiter, Saturn, Uranus, Neptune
• Layered structure
• No solid surface
• Jupiter
• Comet Shoemaker-Levy
• Galileo spacecraft
• Saturn
• Cassini spacecraft

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Moons and Rings of the Outer Planets

• Moons
• Io
• Europa
• Titan
• Rings
• Ice and rock

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Pluto

• Pluto
• Outermost planet
• .3 of earths mass
• Three moons
• Formation
• Captured comet or asteroid
• Still open to question

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A Tenth Planet?

• Xena
• Orbits sun every 560 years
• One moon
• Larger than Pluto

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Asteroids, Comets, and Meteors

• Asteroids
• Small rocky bodies
• Orbit sun
• Most in belt between Mars and Jupiter
• Comets
• Dirty snowballs
• Orbit outside Pluto
• Oort cloud
• Kuiper belt
• Halleys Comet
• Stardust and Deep Impact missions
• Meteoroids, Meteors, and Meteorites
• Meteor showers
• Original solar system material