red shift

• Redshift


  The observed increase in the wavelength of light from distant galaxies
• Redshift


  Provides evidence for the Big Bang theory
• Astronomers in the 1900s detected that light from very distant galaxies has an increased wavelength compared to light from closer galaxies
• Spectrum


  The range of colors produced when white light is passed through a prism
• Dark lines in the solar spectrum are caused by certain elements in the Sun absorbing light of specific wavelengths
• Redshift


  The observed shift of spectral lines towards longer, redder wavelengths
• Redshift


  Indicates that the galaxies are moving away from each other
• Galaxies further away


  Have a bigger redshift and are moving faster
• Nearby galaxies


  Have a small redshift, showing they are moving more slowly
• The fact that distant galaxies are moving faster than nearby galaxies provides evidence for the Big Bang theory
• Big Bang theory


  The theory that the universe began from a very small, extremely hot and dense region that then expanded
• Around 1998, astronomers noticed that the rate of expansion of the universe is actually increasing, rather than gradually slowing down as expected
• Dark matter and dark energy

  Matter and energy in the universe that cannot be detected, which may explain the accelerating expansion