Contents

29 July 1988
Vol 241, Issue 4865

About The Cover

False-color representation of midplane densities in a bar-shaped model of the early solar nebula (the region shown is eight times the earth-sun distance across). Dark colors are high density; white is low. The binary is expected to merge and form a protsun; the planets may have formed in the surrounding nebula. See page 565. [Alan P. Boss, Carnegie Institution of Washington, Washington, DC 20015]