Up, up and away in my beautiful, my beautiful balloon… So the song goes, but what’s it actually like way up high in the atmosphere? Could we humans live up there if we wanted to, or had to? I recall David Attenborough doing a great documentary in the series “The Living Planet” (“The Sky Above” episode, BBC) where he ascended beneath a very large hot-air balloon, complete with oxygen mask and equipment for sampling for life specimens. It was surprising to discover that small insects could be whisked up there and freeze, before descending again and reviving.