The Big Bang

• The Steady State theory

  The universe has always existed similar to how it is today but it is expanding and creating matter to counteract the loss of density.
• Describe the Big Bang theory

  States that the universe expanded from a singular point of very hot dense matter about 14 million years ago.
• What is red-shift?

  A perceived increase in the wavelengths of light due to the source moving away from the observer.
• What does red-shift provide evidence for?

  The universe is expanding, this supports the Big Bang theory
• Compare the observed red-shift of two galaxies

  The further away one is travelling faster so the observed red-shift is greater
• Why is their gaps in sunlight’s emission spectra?

  Chemicals in the sun absorb certain wavelengths of light.
• What did scientists observe to provide evidence that the universe is expanding at an ever faster rate?

  They observed supernovae, which suggest that galaxies are moving away at an ever faster rate
• Prior to observations of supernovae, what was believed about the rate of expansion of the universe and why?

  The rate of expansion was expected to occur more slowly, it was thought that gravitational forces would cause this slowing down.
• What does CMBR stand for?

  Cosmic Microwave Background Radiation
• Where does CMBR originate from?

  The Big Bang, disproving the Stable State theory which does not account for it.
• How does CMBR support the expansion of the universe?

  It is thought that gamma radiation was released in the Big Bang, the expansion of the universe has stretched this radiation, resulting in the microwave radiation present today
• Recessional velocity


  (V) the rate at which a planet is receding away from others
• Speed of light in a vacuum

  3,000,000,000