The Science of Creation The Big Bang Evidence The Science of Creation

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?

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.

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.

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

The Temperature of Space After 500,000 yrs: T=3000K 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!

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

What We See

Cosmic Microwaves Big Bang theory predicted cosmic microwave background. In 1965: discovery of radio waves (microwaves) from sky. Prediction confirmed.

COBE Early 1990s: NASA 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

COBE cont. Also measure the (temperature) intensity and wavelength in various directions. Look for fluctuations out of which galaxies came. V = 600 km/s

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.

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?