Nick,

Your views parallel my own concerning the influence of the Moon upon the Earth. I'm convinced that Earth-like worlds without large moons will become waterworlds. What is not clear to me is whether these waterworlds will become hospitable for life or go into a thermal runaway that turns them into hell worlds like Venus. People have been kicking around the theory that Venus once had an ocean. However I don't know if that theory is based upon respectable science.

Concerning life on a waterworld: I believe there is a concensus starting to form that life originated deep underground. Certainly it is easier to form large molecule hydrocarbons under high heat and pressure. However I've always been uncomfortable with the concept because there doesn't seem to be an easy mechanism for maintaining uniform temperature, i.e. within 20 deg.C of the triple point of water, water at constant pH, transport of waste products and mutation. I've always thought that tidal pools solved all of those sorts of problems nicely. To my mind it seems reasonable that the complex hydrocarbons would be constructed deep underground and then transported into the ocean via submerged volcanic vents. The various hydrocarbons would then be transported to the ocean's surface by thermal convection or bouyancy to form a surface scum. The actual magic of life's genesis would then occur in tidal pools where this surface scum could accumulate and gain exposure to ultraviolet lighat. If this were indeed the process then life could never establish itself on a waterworld due to lack of tidal pools. I should emphasize that I'm an aerospace engineer and know diddly squat about organic chemisty and Precambrian biology (that might actually be an advantage).

Gary