Answer Happy

It is possible to derive the age of the universe given the value of the Hubble constant and the distance to a galaxy, again with the assumption that the value of the Hubble constant has not changed since the Big Bang. Consider a galaxy at a distance.of 255 million light- years receding from us at a velocity, v. If the Hubble constant is 20.5 km/s per million light- years, what is its velocity? (Enter the magnitude in km/s.) km/s How long ago was that galaxy right next door to our own Galaxy if it has always been receding at its present rate? Express your answer in years. Since the universe began when all galaxies were very close together, this number is a rough estimate for the age of the universe. XE Suppose the Hubble constant were not 22 but 13.0 km/s per million light-years. Then what would the critical density (in kg/m³) be? (For H = 22 km/s per million light-years, the critical density is 9.6 X 10-27 kg/m³.) kg/m³ (Ctr)