Estimate the critical density of the universe if the Hubble's constant was 50 km/s/Mpc.
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- The minimum density that is required to stop the expansion of the universe is defined as the critical density. A universe with its density at critical density is said to be flat.
- Critical density is given by,
Here H is the Hubble constant and G is Newton’s gravitational constant.
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Solved in 3 steps
- Using a value for Hubble's constant of 71 km/s per Mpc, find the distance of a galaxy that is receding at a velocity of 1600 km/s.Estimate the critical density of the universe if the Hubble's constant was 100 km/s/Mpc.If you observe light emitted from a distance object when the cosmic background temperature was Tz=54K, what is the redshift z of that light? At that redshift, what was the diameter Dz of the universe at that time compared to the diameter of today's universe D0?