(a) Suppose that Earth once had an atmosphere composed entirely of hydrogen atoms, rather than the molecular nitrogen and oxygen of today. Using Eq. (19.9), calculate the atmospheric escape parameter ν in this case if the temperature of the exosphere was 1000 K.
(b) Using a procedure identical to that of Problem 19.18, estimate the number density of hydrogen atoms in the primordial exosphere.
(c) What would have been the rate of loss of hydrogen atoms from the exosphere?
(d) Assume that the number of atomic hydrogen atoms in the atmosphere was essentially the same as the number of nitrogen molecules today. Approximately how long would it take for the hydrogen to escape from the planet's atmosphere? Express your answer in years and compare it to the age of Earth. (Note: In Section 23.2 we will learn that it appears unlikely that Earth ever had a substantial hydrogen atmosphere.)