Could There be Life Elsewhere in the Solar System or Galaxy?


Emeritus Professor David Moriarty, UQ
This colloquium will be held 12 noon, 23rd September, in Parnell 07-222

If life evolved elsewhere, organisms would depend upon the same physico-chemical processes that apply on Earth and therefore they would be similar. Chemistry deals with deterministic, reproducible events governed by the physical laws and constants that apply throughout the universe. In this talk, I will review recent research into the origin of life on Earth, which will help us to understand whether it is likely that there could be life elsewhere in our solar system, and in the galaxy.  All life is organic, i.e. it is based on the chemistry of carbon and its interactions with oxygen, nitrogen, hydrogen, sulfur and phosphorus. The energy generating processes that sustain the life of all organisms depend on the transition metals, especially iron, copper and nickel. Their role points to the geochemical origins of life on Earth soon after it cooled and oceans had formed. Microbes were the only organisms on Earth for the first 3 billion years. The original prokaryotes — bacteria and archaea — were anaerobic chemoautotrophs using hydrogen as their source of energy and to reduce carbon dioxide and nitrogen to synthesise organic compounds. For the evolution of eukaryotes —complex higher organisms — the transfer of electrons to oxygen is essential for the generation of energy. Oxygen was not present in sufficient concentration until about 2 billion years ago.