Question
(a) Use the distance and velocity data in Figure 3.64 to find the rate of expansion as a function of distance. (b) If you extrapolate back in time, how long ago would all of the galaxies have been at approximately the same position? The two parts of this problem give you some idea of how the Hubble constant for universal expansion and the time back to the Big Bang are determined, respectively.
Question Image
1. The recession velocity is directly proportional to distance from the Milky Way Galaxy. The constant of proportionality, called the Hubble Constant, is on average $1.57 \times 10^{-18}\textrm{ /s}$
2. 20 billion years.
Solution Video