25 August 2000
Vol 289, Issue 5483

About The Cover

Cover image expansion

COVER Scanning electron micrograph of a crater that was created during analysis of a melilite crystal from a calcium-aluminum-rich inclusion in the Allende meteorite. This ~40-micrometer-diameter crater was produced by oxygen ion bombardment during secondary ion mass spectrometry. The results indicate that the sample may have contained short-lived radioactive beryllium-10 at the time of its crystallization in the early solar nebula. See page 1334. [Photo: K. D. McKeegan and G. Jarzebinski]