April Gallery

Aurora borealis or northern lights and Ursa Major

Aurora Borealis. Green, yellow and red Aurora Borealis or Northern Lights display over clouds and trees. The plough in the constellation of Ursa Major is prominent at upper left. Aurorae are caused by the interaction between energetic charged particles from the Sun and gas molecules in the upper atmosphere about 100 kilometres up. A stream of charged particles, called the solar wind, flows out into space continuously from the Sun at speeds of 400-500 kilometres per second. On reaching Earth, the charged particles are drawn by Earth's magnetic field to the poles, where they collide with gas molecules in the upper atmosphere, causing them to emit light

© PEKKA PARVIAINEN/SCIENCE PHOTO LIBRARY

24 Apr 1999

© 2004 TopFoto

Craft, Glasses, Rural Workmanship, Sport, Stitches The Leather, Used In Kent A Chronicle Of The Century 1950 70, Workshop, Yesterday 259

Particle tracks on geometric patterns

Particle tracks and geometrical patterns. Computer illustration of subatomic particle tracks (white & yellow) and geometrical patterns (pink) on a starfield. The tracks result from particles moving through a bubble chamber containing a superheated liquid. The disturbance of the liquid by the particles causes it to boil, so that tracks of minute bubbles are left in the wake of the particles which can be photographed and studied. Each particle has a distinct pattern, allowing it to be easily identified. Particle physics has revealed the basic structure of the atoms from which everything is made

© MEHAU KULYK/SCIENCE PHOTO LIBRARY