Images Dated 1st December 2004

Visualisation of primordial quark/gluon plasma

Visualisation of the early universe. This image depicts particles in the quark-gluon "soup" which existed less than one millionth of a second after the Big Bang. Quarks are shown in red, green and blue; anti-quarks are cyan magenta and yellow. Other colours are gluons. The grey particles are electrons and electroweak force bosons. Gluons are the carriers of the strong nuclear force, but at the high energy density of the universe at this time (a million billion degrees temperature), quarks would not have been confined by the force. As the universe continued to expand, and the temperature dropped, the quarks were able to combine into baryons such as protons and neutrons

© ARSCIMED/SCIENCE PHOTO LIBRARY

Sand food plants

Sand food plants (Pholisma sonorae). These mushroom-shaped parasitic plants are native to the deserts of south-western USA and Mexico. They are found growing on shifting sand dunes. Their scaly stems were eaten raw or cooked by Native Americans. They contain no chlorophyll and therefore cannot produce their own food. Instead, their stems, which extend 1-2 metres below the ground, are attached to the roots of nearby host plants. This unusual plant has become endangered. It is threatened by off-road vehicles and the development of the desert. Photographed in the Algodones wilderness, California, USA

© DR TORSTEN WITTMANN/SCIENCE PHOTO LIBRARY

Comet Hale-Bopp and aurora borealis, 30 March 1997

Comet Hale-Bopp. Optical image of comet Hale-Bopp 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 comet's 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 Earth's upper atmosphere. Comet Hale-Bopp was discovered on 23 June 1995. Photographed on 30 March 1997 in Finland

© Pekka Parviainen/Science Photo Library