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For large redshifts, we can no longer write v = cz because we need to apply corrections from Einstein's relativity and t
Posted: Wed May 04, 2022 1:42 pm
by answerhappygod
- For Large Redshifts We Can No Longer Write V Cz Because We Need To Apply Corrections From Einstein S Relativity And T 1 (44.66 KiB) Viewed 44 times
For large redshifts, we can no longer write v = cz because we need to apply corrections from Einstein's relativity and the acceleration of the universe. The math is a little messy, but Ned Wright, a cosmologist at UCLA, has kindly provided a cosmology calculator for this purpose:
http://www.astro.ucla.edu/-wright/CosmoCalc.html. Note that the cosmology calculator assumes H0 69.6, Omega M = 0.286 (the density of the local universe / critical density), and Omega_vac=0.714 (a measure of the acceleration of the expansion of the universe. Use NED (ned.ipac.caltech.edu) to look up the redshift (z) for the QSO 3C48: Enter that redshift into the cosmology calculator, and click the "General" button to perform the calculation. Read off the following values from the calculator. The lookback time (light travel time): billion years. The age of the universe when light left 3C 48: billion years. Mpc. The Hubble law distance (co-moving radial distance): Finally, calculate the Hubble law distance (cz/ Ho) without using the cosmology calculator. Use Ho = 69.6, the same value used by the cosmology calculator. This calculation will give you à feel for the size of the additional corrections. Uncorrected distance = cz / Ho= Mpc. Check alt A SHA MA - 288