Contents

10 September 1999
Vol 285, Issue 5434

About The Cover

Cover image expansion

COVER NASA Hubble Space Telescope image of galactic nebula NGC 3603 with a young star cluster (center) and evolved blue supergiant Sher 25 (ringed star, upper left center). Giant nebula cloud (right) contains "amorphous" silicate dust grains. Similar extraterrestrial dust grains called GEMS (glass with embedded metal and sulfides), which were collected in Earth's stratosphere, may be remnants of the nebula cloud from which our solar system formed. See page 1716 [Image: W. Brandner, E. K. Grebel, Y.-H. Chu]