Contents

17 April 1998
Vol 280, Issue 5362

About The Cover

The large-scale structure of the universe is believed to be weblike, as revealed in this supercomputer simulation. The image shows a three-dimensional isosurface of the baryonic material (gas) in a volume that is 175 by 130 by 175 million light years on a side. A rich cluster of galaxies has formed at the center of the volume. Material continually accretes onto the cluster along the filamentary structures, giving rise to the stormy infracluster conditions discussed in the Review beginning on 400. [Image: Chris Loken, University of Missouri-Columbia]