On 26 September 1991, eight people were sealed inside Biosphere 2, a three-acre enclosure of glass and steel near Oracle, Arizona. They stayed for two years. And the oxygen in their sealed atmosphere did fall, slowly and persistently, until it reached a level low enough to be a genuine medical problem and outside oxygen had […]
On 26 September 1991, eight people were sealed inside Biosphere 2, a three-acre enclosure of glass and steel near Oracle, Arizona. They stayed for two years. And the oxygen in their sealed atmosphere did fall, slowly and persistently, until it reache... [5600 chars]

