Discussion of An alternative Venus by

Warren Hamilton’s article is clearly the result of very detailed study of Venusian surface features. Venus is the only planet in our solar system for which we have to rely on radar images and this in itself provides additional constraints on interpretation. Hamilton has carefully considered the likely radar image obtained from different geological materials: e.g. basalt, sediments, breccias etc. He readily admits that his interpretations conflict with the interpretations of the conventional school of J.W. Head and others. It is a remarkable fact that, whereas for the Moon, Mercury, Mars and the many planetary satellites the conventional wisdom is virtually to apply Impact (rather than volcanism) as an ‘a priori ’ or ‘default ’ explanation for any craters or circular structures of disputed origin, the reverse is the case for Venus. Volcanic processes are invoked except for about 1000 ‘undisputed young pristine ’ Venusian craters. Hamilton rightly suggests that ‘pristine ’ has been in many cases incorrectly used, and many are by no means pristine. In this space age, conventional interpretations tend with the passage of years to be taken as ‘graven in stone’, but of course they are not. I remember well a meeting in London at which Dan McKenzie put forward a quite different interpretation of Venus, rejecting the conventiona