GCSE Physics (AQA)

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Explaining Red-Shift

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Space physics Red-shift

Explaining Red-Shift

6:06 The Origin of the Universe
Spec 4.8.2
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  • Light waves experience the Doppler effect when a light source moves relative to an observer.
  • The Doppler effect involves waves being stretched or squashed, changing their wavelength.
  • Moving a light source towards an observer decreases the wavelength (blue shift).
  • Moving a light source away from an observer increases the wavelength (redshift).
  • Redshift occurs when visible wavelengths shift towards the red end of the spectrum.
  • Blue shift occurs when visible wavelengths shift towards the blue end of the spectrum.
  • Redshift and blue shift are observed when analyzing light from distant galaxies and stars.
  • Light from a galaxy moving away from us is redshifted.
  • The Doppler effect explains why light from distant galaxies is redshifted.
  • Analyzing light involves refracting it into an emission spectrum, where certain wavelengths may be missing.
  • A redshifted emission spectrum indicates a galaxy moving away from us.
  • The amount of redshift varies depending on the speed of the galaxy.
  • Faster-moving galaxies cause a greater redshift effect.
  • Emission spectra can be used to compare the motion of different galaxies.
  • Blueshift effects are observed if a galaxy is moving towards us.
  • There are few galaxies moving towards us in the universe.
  • A blueshifted emission spectrum indicates a galaxy moving towards us.
  • Understanding emission spectra is important for explaining galaxy motion in exams.

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