Sunrise in space. View of the rising Sun, photographed by the crew of an orbiting Space Shuttle during Mission STS-45 (24 March - 2 April 1992). The Sun is clearly visible from this altitude (286km), but to ground-based observers the Sun is still below the horizon. The dark band to either side of the Sun is caused by aerosols in the stratosphere. These mainly consist of sulphuric acid crystals, and scatter the sunlight. The bright band above this is caused by secondary scattering of the sunlight, whilst the reddish band below the Sun is light reflected from cloud tops. The aerosols entered the atmosphere following the Mt Pinatubo eruption in 1991.