Noctilucent clouds over Canada
Noctilucent clouds over Canada
On 26 July 2014, during his ‘Blue Dot’ mission on board the International Space Station, German ESA astronaut Alexander Gerst took this photograph of what are referred to as a ‘noctilucent clouds’. These are formed when ice crystals accumulate above the mesosphere, at an altitude between 81 and 85 kilometres.
