By now, you have probably read or heard that our polluting ways have reached a critical point, where Earth is rapidly approaching total failure as a planet. Perhaps you have wondered how we humans could have managed to do so much damage in so little time.
Permanent settlements in space will require forms of localized government that are likely to differ from contemporary models of political order. This article thus asks a provocative question associated with the empirical record of human colonization and settlement in prior eras: What sort of authoritarian governance is most likely to form in human space settlements during the medium term?
The formula for collisional excitation of the atoms responsible for auroral emission can explain why green auroras from excited oxygen atoms can occur at relatively low altitudes, but red auroras from these same atoms are constrained to higher altitudes of lower density. The same formula also suggests much lower electron velocities (~100 km/s) than are required to excite the oxygen atoms to the required metastable levels for subsequent emission (~1000 km/s).
