If H is the rate at which the universe expands in km⁄s⁄Mpc, then the Hubble time is t = 1⁄H. Find the Hubble time in billions of years. One Mpc equals 3.26 million ly, or approximately 3 × 1019 km, the most precise modern measurements of H yield a value of 70 km/s/Mpc. Please round your answer to three significant figures. billion years.
Is this time an underestimate, an overestimate, or neither for the age of the universe?