Contents

14 September 2007
Vol 317, Issue 5844

About The Cover

Cover image expansion

COVER Supercomputer simulation of the filamentary environment in which the very first stars formed, 100 million years after the Big Bang. The filaments, about 9000 light-years in length, are characteristic of a model universe in which the dark matter consists of fast-moving elementary particles. See page 1527. Image: Liang Gao and Tom Theuns, Institute for Computational Cosmology, Durham University