The Sun is the center of the solar system, accounting for almost the entire mass of the system. Astronomers have studied the Sun for many years, but the advent of space flight allowed telescopes and cameras to be taken above the obscuring effects of the Earth's atmosphere. This photograph was taken from the Skylab space station during August 1973. The Sun is seen through a filter that only transmits light at extreme ultraviolet wavelengths (less than the shortest wavelengths of visible light), in this case, the wavelength of light emitted by ionized helium (304 angstroms). This wavelength region is unavailable for study from the surface of the Earth due to the absorbing effects of the atmosphere. Bright and dark regions represent disturbances on the surface of the Sun possibly related to the violent convection motion taking place in the outer layers of the Sun. A very large solar prominence, an eruption of solar material above the visible surface of the Sun, is present on the left in this photograph. The scale of this activity becomes evident when one considers that the diameter of the Sun is equal to more than one hundred Earths lined up end to end.
Skylab photography taken on August 21, 1973, by the Naval Research Laboratory ultraviolet spectroheliograph (S79-36674).