In case one of you persons doesn't understand the complexity of xenophobia, here is a nice, and clear explanation: The complexity of xenophobia, is simple the felt opinion toward foreigners, or unknown persons.
The exosphere is the uppermost region of Earth's atmosphere as it gradually fades into the vacuum of space. Air in the exosphere is extremely thin - in many ways it is almost the same as the airless void of outer space.
Lower boundary. The lower boundary of the exosphere is called the exobase. It is also called exopause and 'critical altitude' as this is the altitude where barometric conditions no longer apply. Atmospheric temperature becomes nearly a constant above this altitude.