MEHAU KULYK / SCIENCE PHOTO LIBRARY MEHAU KULYK / SCIENCE PHOTO LIBRARY
Particle tracks and cosmology. Computer illustrat- ion of subatomic particle tracks (yellow) and concentric rings on a spiral galaxy. The tracks result from charged particles moving through a bubble chamber containing a superheated liquid. Ionisation of the liquid by the particles causes it to boil, so that tracks of minute bubbles are left in their wake. Each particle makes a distinct track, such as the spirals made by electrons and positrons. Galaxies are independent groups of stars bound together by mutual gravitational attraction. Particle physics has revealed the basic structure of the atoms which form everything in the universe.
Model release not required. Property release not required.