Albert Libchaber: "The Origin of Life: from geophysics to biology?"
The main thesis of the talk was to suggest that temperature differences can account for a diverse range of important physical and biological phenomena. For example, continental drift can be shown to occur because of temperature differences between the mantle layer of the Earth (hot) and the outer crust (cold). The lecturer showed results of clever experiments to simulate that movement. But that was just a teaser.
The main point of the lecture was to show that life itself could have originated because of such temperature differences, given the right "raw material". Specifically, at the bottom of the oceans where the crust meets the mantle, there exist vents that push extremely hot streams (300°C) up in the surrounding cold (2°C) ocean water. These streams contain all the Earth minerals which are the basic constituents of organic material. The thesis expressed by the lecturer is that those temperature differences cause fluid movement accompanied by wide temperature variation, during which DNA can be multiplied exponentially. It is this feature that according to him could lead to the original assembly of microorganisms. Indeed, a rich fauna or organisms does exist near those thermal vents, including species not found elsewhere on Earth. Again, the lecturer showed an experiment to demonstrate the replication of DNA in the laboratory with conditions that emulate that of the ocean floor.
The point I failed to understand was the origin of the first strand of DNA, or the process by which inorganic material assembles itself. I expect the answer would have been along the lines of "Evolution did it!". In fact, Libchaber joked during the lecture about attributing to evolution whatever cannot be explained, which resonated with my own thoughts on how one name can be substituted with another, but the underlying human faith remains the same.