Contents

27 November 1987
Vol 238, Issue 4831

About The Cover

A white-light image of an active region on the sun taken by the Solar Optical Universal Polarimeter instrument during the Spacelab-2 mission on board the space shuttle Challenger. The granular structures are due to convection in the solar atmosphere. The dark sunspot is a region of strong magnetic fields and is approximately 14,000 kilometers in diameter. See page 1264. [Lockheed Palo Alto Research Laboratory, Palo Alto, CA 94304]