Comet HaleBopp. Optical image of comet HaleBopp over silhouetted trees and the glow of the aurora borealis (Northern Lights). Both the gas and dust tails of the comet are seen. The gas or ion tail (blue) consists of ionized glowing gas blown away from the comet head by the solar wind. The dust tail (white) consists of grains of dust pushed away from the comet head by the radiation of sunlight. A comets tail always points away from the Sun. The luminous light of the aurora borealis is caused by charged particles from the Sun inter acting with the Earths upper atmosphere. Comet HaleBopp was discovered on 23 June 1995. Photographed on 30 March 1997 in Finland.