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The Big Bang Evidence

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... Universe 1000x bigger. lpeak = 1000x longer. lpeak = microwaves (radio). T = 3K! Where do you look? Recall Lookback time. Universe is a time machine. – PowerPoint PPT presentation

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Title: The Big Bang Evidence


1
The Big Bang Evidence
  • The Science of Creation

2
Goals
  • What is the evidence for the Big Bang?
  • What predictions does the Big Bang theory make?
  • What observations can we make?
  • How good of a theory is the Big Bang?

3
Scientific Evidence
  • A scientific model must do two things
  • Explain what is seen.
  • Predict what will happen accurately.
  • Or, predict what can be seen before one thinks to
    look.

4
Cosmic Microwave Background
  • The Big Bang
  • Massive amount of energy.
  • Very high temperature ? thermal radiation
  • As Universe expands
  • Temperature cools ? thermal radiation gets
    redder.
  • or
  • Cosmological redshift ? same thing.

5
Origin of the CMB
  • Once cool enough for atoms, radiation could move
    freely through space.

6
The Temperature of Space
  • After 500,000 yrs T3000K
  • lpeak a 1/T
  • lpeak near infrared.
  • The Universe was red.
  • After 16 billion yrs
  • Universe 1000x bigger.
  • lpeak 1000x longer.
  • lpeak microwaves (radio).
  • T 3K!

7
Where do you look?
  • Recall Lookback time.
  • Universe is a time machine.
  • Look beyond the youngest galaxies.
  • Look everywhere.

8
What We See
9
Cosmic Microwaves
  • Big Bang theory predicted cosmic microwaves
    background.
  • In 1965 discovery of radio waves (microwaves)
    from sky.
  • Prediction confirmed.

10
COBE
  • Early 1990s
  • NASAs Cosmic Background Explorer
  • Measure the intensity of radiation at many
    wavelengths.
  • 3K thermal emission!

lpeak (3 x 10-3 m/K) / 3 K 0.001m 1mm
11
COBE cont.
  • Also measure the (temperature) intensity and
    wavelength in various directions.
  • Look for fluctuations out of which galaxies came.

V 600 km/s
12
(No Transcript)
13
Olbers Paradox
  • Why is it dark at night?
  • In an infinite and unchanging universe
  • Every line of sight should end at the surface of
    a star.

14
A Good Theory?
  • The Big Bang is a very successful theory.
  • Makes predictions
  • CMB.
  • Hydrogen, Helium, Lithium abundances.
  • Formation of structure.
  • Expansion of Universe.
  • Are other Creation theories
  • Scientific?
  • Successful?
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