GENERAL KNOWLEDGE

Detailed explanation-1: -Ever since 1929, when Edwin Hubble discovered that the Universe is expanding, we have known that most other galaxies are moving away from us. Light from these galaxies is shifted to longer (and this means redder) wavelengths-in other words, it is ‘red-shifted’.

Detailed explanation-2: -The American astronomer Edwin Powell Hubble reported in 1929 that the distant galaxies were receding from the Milky Way system, in which Earth is located, and that their redshifts increase proportionally with their increasing distance.

Detailed explanation-3: -This type of redshift is called the cosmological redshift. And here’s the relation between distance and redshift: the further away a galaxy is, the longer its light takes to reach us. A longer light travel time means more cosmic expansion, more wavelength stretching and thus a higher redshift.

Detailed explanation-4: -Hubble’s Law They found that the larger the distance a galaxy is away from us, the larger the redshift of its spectral lines. If the redshift is due to a relative velocity between the galaxy and ourselves, this shows that the further away a galaxy is from us, the faster it moves away from us.