That “final” point is around 10,000 km up above the surface – so it’s unsurprising that some people want a line marking where the atmosphere ends and space begins a little closer to Earth. “The higher up you go, the thinner the atmosphere gets, and it keeps getting thinner and thinner and thinner, until eventually you can’t tell that it’s there anymore.” “Where space starts and the atmosphere ends is a little bit like that, in that the atmosphere doesn’t just suddenly stop,” he says. Our age is a continuum, Horner says, and the threshold for driving or drinking is arbitrarily defined. Richard Branson’s Virgin Galactic flight on 12 July rocketed up to 86 km off the ground, while Jeff Bezos’s Blue Origin flight last night reached just over 107 km – but did either of them truly leave this planet?Īccording to Jonti Horner, an astronomer at the University of Southern Queensland, “It’s one of those questions that’s a bit like saying, ‘When are you old enough to drink?’ or ‘When are you old enough to drive?’ Every country has their own version of an answer.” Boeing boosts Australia into the aerospace major leagueĪs billionaires blast off in an effort to secure bragging rights or stroke their egos, an old question has been reignited: where does the atmosphere end and space begin?.Carbon offsets for flights: dinkum deal, or pie in the sky?.Robot pigeon promises new flying machines.