Earth Science

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Earth Science

• Chapter One Review

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What is Earth Science?
Study of the Earth and all of its components

• Geology - study of the solid Earth
• Paleontology - study of fossil record
• Hydrology - study of water
• Oceanography - study of oceans
• Astronomy - study of the universe
• Biology - study of living organisms

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Why Study Earth Science?
Duh! Isnt it obvious! We live here.
Or do we?

• Average American child spends about 30
  minutesoutside a week in activities
  (Hofferth,Sandberg, 2000)
• How many people grow their own food?
• How do you make steel?

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Review Where do we live?
Here
http//www.nineplanets.org/earth.html
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Do we have kids?
LUNA Orbit 384,400 km from Earth Diameter
3476 km Mass 7.35e22 kg
Less dense than Earth more like the composition
of the mantle and crust of Earth Heavily
cratered surface about 4 billion years
old Synchronous orbit/rotation means same side
faces us
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Who are our neighbors?
Terrestrials - planets composed mostlyof rock
and metals found in the innerpart of the Solar
System

• High density - 4-5 gm/cm3
• Few moons (Mars has two asteroids)
• Slow rotation
• Solid surfaces
• No rings
• Relatively small

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Who lives nearby?
Jovians - planets composed mostlyof hydrogen and
helium, with ice/rock cores

• Low density - .7-1.8 gm/cm3
• Many moons
• Rapid rotation
• Deep atmosphere unknown surface
• Rings
• Large

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And their kids

• Over 70 known jovian moons
• Mostly rock and ice
• Some larger than Mercury some smaller than
  asteroids
• Larger ones have atmospheres
• Hints of liquid water on a few, like Europa
• Later this year, we hope to have our first
  landing on a jovian moon

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Assorted Neighborhood Ruffians

• Pluto - more like a jovian moon than a planet
• Trans-Neptunian objects - recent discoveries of
  Pluto-sized objects very far out (90 AU)
• Asteroids - most found in belt between Mars and
  Jupiter some come near Earth mostly rock and
  metal
• Comets - mostly ice, with some rock come near
  the Sun spend most of their time out beyond
  Saturn
• Kuiper Belt - disk-shaped region beyond Neptune
  that contains icy bodies
• Oort Cloud - spherical region beyond KB comet
  nursery

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Geology, Past and Present
We have only been watching the planet for a very
shorttime. How do we know what happened in the
past?

• Uniformitarianism - processes happening today
  have occurred at similar rates throughout
  history. Ex. Sand erosion on a beach
• Catastrophism - changes in nature occur because
  of large, violent events. Ex. hurricane, flood

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Past, contd.
Both views of nature are required to explain what
happened in the past, and what we see happening
today.
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Nature and Rate of Population Growth

• Human population has been growing at an
  exponential rate currently more than 1 a year
• Doubling Time - exponential growth results in a
  doubling at constant intervalsDT (70
  years)/(percent growth)What does this mean for
  the Earth?