The Big Bang Model of the Origin of the Universe related to Cosmological Red Shift

  • The Big Bang model is the most widely accepted explanation for the origin and evolution of the Universe. According to this theory, the Universe began about 13.8 billion years ago from a very hot and dense point known as a singularity.

  • The Big Bang model states that the Universe has been expanding since its creation. Over time, this expansion causes galaxies to move away from each other.

  • The concept of cosmological redshift is a direct result of this expansion. When we look at distant galaxies, we find that the light from them appears more red than it should be. This shift towards the red end of the spectrum is known as ‘redshift’.

  • Cosmological redshift occurs due to the stretching of space. As the Universe expands, space between galaxies also stretches. This also stretches the light waves travelling through it, causing them to have longer wavelengths. Longer wavelengths of light are associated with the red end of the spectrum, hence the term ‘redshift’.

  • Edwin Hubble was the first to document cosmological redshift. He found that not only are galaxies moving away from us, but the further away a galaxy is, the faster it’s moving away. This supports the concept of an expanding Universe.

  • The redshift of a galaxy is measured by comparing the wavelengths of light we receive from it to the wavelengths we would expect to see if the source was stationary. The greater the redshift, the faster the galaxy is moving away.

  • To calculate the redshift (z), the formula used is: z = (observed wavelength - rest wavelength) / rest wavelength.

  • Observations of cosmic microwave background radiation also support the Big Bang model. This is the residual heat left over from the initial explosion, which can be detected from any direction in space.

  • The Big Bang model doesn’t explain what caused the explosion or what, if anything, existed before it. This is one limitation to the model.

  • Other theories exist, but the Big Bang is currently the best explanation for the Universe’s origin based on the evidence we have.