Astronomy 100

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Astronomy 100

• The Beginning and End of the Universe

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• Now Explain the Big Bang to someone near you.
  Speculate how will the Universe end?
• Goal
• Understand the basic theory of the Big Bang.
• Understand that the Universe is expanding.
• Understand the Big Three possibilities for the
  end of the Universe.
• Know the main evidence that supports these.
• Vocabulary Big Bang Theory, raisin bread, Cosmic
  Microwave Background Radiation, Redshift, Dark
  Matter, Inflation, Acceleration, Dark Energy

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Once Upon a Time

• There were four men Digges, Kepler, Halley, and
  Olbers.
• If the Universe is infinite, why is the sky
  black?
• The observable universe is NOT infinite, in fact,
  it has a beginning. Whoa. Edgar Allen Poe was the
  first guy to suggest this.

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Then

• So, along comes another guy Hubble.
• All galaxies are red-shifted (moving away from
  us) and theyre red-shifted more the further
  away they are.
• The universe is expanding.

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http//www.youtube.com/watch?vFB0KsSrZbXYRaisi
n Bread analogy
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• If everything is expanding, it must have started
  sometime.
• The Big Bang
• Happened everywhere at once
• 14 Billion Years Ago
• But we need more evidence

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Along came

• Penzias and Wilson.
• And some pigeons

http//www.pmobs.org.au/cosmology1.html Pigeon
from Amy Ritalin http//farm1.static.flickr.com/1
45/356393902_457b344514_o_d.jpg
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They thought it was pigeon poop
This is actually WMAP more detailed than what
Penzias and Wilson saw. http//map.gsfc.nasa.gov/m
edia/080997/080997_5yrFullSky_WMAP_1024W.jpg
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• Were looking back in time.
• It was SUUUUUUUUUUUUPER hot. All energy.
• Thats what were seeing its about 3oK now.
• Since then the Universe has been cooling, and now
  we have matter instead of just energy.

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Okay, so heres the thing

• We know the Universe is expanding, but is it
• Expanding and slowing down
• Expanding and speeding up, or
• Expanding and staying the same?
• Two groups of people used the Hubble Telescope
  they say expanding.
• WHAT ABOUT GRAVITY?

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• This is (one of the places) where Einstein came
  in.
• He added the Cosmological Constant something
  we currently refer to as Dark Energy.
  (Quintessence is another idea)
• Extra inexplicable energy thats pushing the
  Universe apart.

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And thats where we are today.

• Dark Energy is confusing to us,
• But this is the theory as it stands
• 14 Billion Years ago the Big Bang happened
  everywhere.
• The Universe has been expanding since.
• That expansion is accelerating.
• Eventually we will
• rip apart? (The Big Rip)
• We dont know yet. Chandras working on this.

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• Answer Now
• Where is the center of the Universe? Where is the
  edge?
• How can we expand without a center?
• What is the CMBR? Why is it important?
• Define 1 Big Bang Theory, raisin bread,
  Redshift, Dark Matter, Inflation, Acceleration,
  Dark Energy, Cosmological Constant