Cosmological Red Shift

Cosmological redshift is a key concept which is used to explain how our universe is expanding.
It refers to the shift in the light observed from distant galaxies towards the red end of the spectrum. This is also known as the “Doppler effect”.
The redshift occurs because the galaxies are moving away from the observer (earth) due to the expansion of the universe.
The Doppler effect is the change in frequency of a wave in relation to an observer who is moving relative to the source of the wave.
In cosmological terms, the red end of the spectrum represents a lower frequency and longer wavelength.
The greater the redshift, the farther away the galaxy and the faster it is moving away.
Edwin Hubble, an American astronomer, confirmed the redshift-distance relation in 1929 - this is also known as Hubble’s law.
Hubble’s law means that redshift can be used to estimate the distances to faraway galaxies.
The observational data supports the Big Bang theory which proposes that the universe started from a small singularity and expanded over the next 13.8 billion years to the cosmos that we know today.
Cosmological redshift is different from gravitational redshift which is caused by the effects of gravity on light or other electromagnetic radiation.
Redshift can be used to estimate the rate of expansion of the universe, a value called the Hubble Constant.