Solar prominence. Coloured ultraviolet image of a giant eruptive solar prominence, recorded on 21 August 1973 by the crew of the Skylab space station. The image was recorded at a wavelength of 30.4 nanometres using the Extreme Ultraviolet Spectroheliograph instrument. Eruptive prominences originate as normal prominences - dense clouds of gas supported by the magnetic fields that link adjacent groups of sunspots. Occasional rapid changes in the shape of such a magnetic field can occur, and the distorted magnetic field catapults the prominence gas into space. The large yellow area at the top of the disc is an active region associated with a sunspot group.