Some highlights of the planetary sciences sessions at the spring Meeting: A Collection of reports: Venus

The Venus session was devoted exclusively to observations during the 1962 conjunction, including the Mariner radiometer results. F. T. Barath, A. H. Barrett, J. Copeland, D. E. Jones, and A. E. Lilley presented the results of the Mariner microwave measurements. Only the 19-mm data have been analyzed but they show definite and significant limb darkening, thus demonstrating that the source of the intense radio emission is the surface of Venus. After eliminating the limb darkening and dividing the resulting brightness temperature by an assumed surface emissivity, a fairly uniform actual surface temperature of about 700°K was obtained. T. Gold commented during the discussion that part of the limb darkening could be due to anisotropy in the surface emissivity. The authors agreed, and L. D. Kaplan pointed out that this would not invalidate the conclusion that a hot surface was the primary source of the cm emission.