The Big Bang Theory

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The Big Bang Theory

• By Dan Miller

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Overview

• Following the expansion of the universe backwards
  through time using general relativity reveals a
  point of infinite density and infinite
  temperature at a finite time in the past. This
  singularity indicates a breakdown of general
  relativity. This early hot, dense phase of the
  universe is what is referred to as The Big
  Bang.

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The Origin of The Big Bang Theory

• In 1927, the Belgian priest Georges Lemaître was
  the first to propose that the universe began with
  the explosion of a primeval atom. 1
• Years later, Edwin Hubble found evidence to
  justify Lemaître's theory. He found that distant
  galaxies in every direction are moving away from
  us with speeds proportional to their distance. 1

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Discoveries/EvidenceBackground Radiation

• The theory predicts the existence of cosmic
  background radiation (CMBR), which is the glow
  left over from the explosion itself. This was
  confirmed when the radiation was discovered in
  1964 by Arno Penzias and Robert Wilson, who later
  won the Nobel Prize for this discovery. 1

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NASAs COBE Mission 2

• The COBE satellite was developed by NASA to
  measure the diffuse infrared and microwave
  radiation from the early universe.
• It discovered fluctuations in the CMBR which are
  predicted by Inflationary Big Bang models.

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NASAs WMAP Mission 4

• WMAP has produced a new, more detailed picture of
  the infant universe. Colors indicate "warmer"
  (red) and "cooler" (blue) spots. The white bars
  show the "polarization" direction of the oldest
  light. This new information helps to pinpoint
  when the first stars formed.

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Big Bang Time Cone
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Theoretical Problems

• Two major dependencies
• The universality of physical laws
• The cosmological principle 7
• Singularity
• Horizon Problem
• Flatness Problem

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Conclusions

• While the Big Bang model is a well established
  theory, it will probably be refined in the
  future. As of now it provides an explanation of
  the origin of the Universe that fits the
  observations that have been made surrounding it.

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Citations

1. http//liftoff.msfc.nasa.gov/academy/universe/b_ba
   ng.html Big Bang Theory Background Nasa
2. http//lambda.gsfc.nasa.gov/product/cobe/ COBE
   Mission Information and Pictures
3. http//en.wikipedia.org/wiki/Graphical_timeline_of
   _the_Big_Bang Big Bang Timeline Wiki
4. http//map.gsfc.nasa.gov/m_mm.html WMAP Mission
   Results
5. A Brief History of Time Book citation
6. http//snap.lbl.gov/multimedia/presentations/after
   bigbang/img0.html big bang presentation
7. http//en.wikipedia.org/wiki/Big_Bang Wiki entry
8. http//www.simonsingh.net/Big_Bang.html big bang
   history