Question

How is redshift calculated?

Answer 1

There are four steps (as given below) in identifying red shift.

Explanation:

Measuring a red-shift or blue-shift requires four steps. First step is to find the spectrum of something celestial body (like a galaxy) that shows spectral lines. Next we identify (from the pattern of lines) which line was created by which atom, ion, or molecule. Then we measure the shift of any one of those lines with respect to its expected wavelength. And finally, we use a formula that relates the observed shift to the object's velocity.