Physics Astronomy

Doppler Effect

• Change in frequency of a wave in relation to an observer who is moving relative to the wave source
  • A stationary source produces waves with a specific wavelength
    • Could be sound waves, light waves, etc.
    • An observer some distance away expects to "see" the waves with the same wavelength
  • If the source moves towards/away from the observer, the observer will see the Doppler effect
    • Shift in observed wavelength
• Each successive wave crest is emitted from a position closer/further from the observer than the crest of the previous wave
  • Each wave takes slightly less/more time to reach the observer than the previous one

Redshift

• Increase in wavelength
• Decrease in frequency and photon energy
• Occurs when two objects are moving apart

Blueshift

• Decrease in wavelength
• Increase in frequency and photon energy
• Occurs when two objects are moving closer to each other