Red-shift

• What is the phenomenon called when an object emits waves and the wavefronts spread out symmetrically?

  Galactic Red-shift
• What happens to the waves when the source of the waves moves?

  The waves can become squashed together or stretched out
• What changes occur to the wavelength and frequency of waves when a source moves towards an observer?

  • Wavelength in front decreases (λ – Δλ)
  • Frequency increases

  
• What changes occur to the wavelength and frequency of waves when a source moves away from an observer?

  • Wavelength behind increases (λ + Δλ)
  • Frequency decreases

  
• What is the effect called that describes the change in wavelength and frequency due to the motion of a wave source?

  The Doppler effect

  
• What happens to the wavelength of light when an object moves towards an observer?

  The wavelength of light decreases
• What is the term used when light moves towards the blue end of the spectrum?

  Blueshift
• What is the term used when light moves towards the red end of the spectrum?

  Redshift
• What will be observed when light from a star moving towards an observer?

  The light will be blueshifted

  
• What will be observed when light from a star moving away from an observer?

  The light will be redshifted
• What does the observer in front of a moving object observe?

  A blue shift

  
• What does the observer behind a moving object observe?

  A red shift
• Which color of light has the longest wavelength and smallest frequency?

  Red light
• How does the sound of a motorbike change as it travels past and then away from you?

  • As it moves away, the pitch becomes lower
  • Frequency decreases
  • Wavelength increases
• What does the redshift of light from distant galaxies indicate?

  • Galaxies are moving away from us
  • The universe is expanding

  
• What does the observation of redshift from distant galaxies support?

  The Big Bang theory
• What is the relationship between the distance to a galaxy and its redshift?

  The greater the distance, the greater the redshift

  
• How long ago did the universe begin according to the Big Bang theory?

  Around 14 billion years ago
• What was the state of the universe at the time of the Big Bang?

  It was extremely hot and dense
• What happens to the universe after the Big Bang?

  • The universe expands
  • It cools as it expands
  • Each point expands away from the others
• What is observed about galaxies as a result of the universe's expansion?

  Galaxies are moving away from each other
• What is the evidence for the Big Bang?

  • Light spectrums from supernovae show redshift
  • Distant galaxies are receding faster

  
• What happens to matter during an explosion in the context of the Big Bang?

  It moves out in all directions
• How does the speed of matter relate to its distance from the source of an explosion?

  Lighter matter travels faster and further
• What would happen if you traveled back in time to observe the galaxies?

  They would become closer together
• What is the relationship between the speed of galaxies and their distance from us?

  • Faster galaxies are further away
  • Slower galaxies are closer
• What is dark matter?

  Unseen matter in the universe that we cannot account for
• What does the evidence from the expansion of the universe suggest about its rate of expansion?

  The universe is expanding at a faster rate
• What is dark energy suggested to do in the universe?

  It pushes everything in the universe apart
• What is the expected outcome of gravity in the universe?

  Everything will eventually become closer together
• Why is dark energy considered a possible solution in the universe?

  • It could counteract gravity
  • It could be responsible for the universe's expansion
• Why is the topic of dark energy and dark matter engaging for students?

  • It presents current mysteries in physics
  • It sparks interest in studying physics at a higher level