Using Ho = = 20.8 km/s/Mly and assuming the expansion rate has been constant, find out how long the universe has been expanding.
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- What would be the critical density of matter in the universe if the value of the Hubble constant were (a) 40 km/sec/ Mpc? (b) 90 km/sec/Mpc?By what factor would the critical density of the universe today change if the Hubble constant today measured at 5 times greater than what we previously thought?At what temperature is the thermal radiation in the universe energetic enough to produce nucleons and antinucleons?