Keep pulling the thread on Nick Lane.
Eukaryotic cells, which form the basis of all complex life on Earth, arose only once in the planet's history.
The origin of eukaryotes was a singular event that occurred approximately 2 billion years ago, after 2 billion years of simpler life on Earth.
The key event that enabled the evolution of complex eukaryotic life was the acquisition of mitochondria.
The theory of abiogenesis in deep-sea hydrothermal vents, proposed by Bill Martin and Mike Russell, suggests life originated in cell-like pores within a mineralized sponge structure, utilizing a natural proton gradient between alkaline vent fluids and an acidic early ocean.
Evidence for alkaline hydrothermal vent systems, similar to those proposed for the origin of life on Earth, currently exists for early Mars and the moons Enceladus and Europa.
The primary bottleneck preventing the widespread existence of complex, intelligent alien life is likely the rare, singular event of eukaryogenesis, not the origin of simple life itself.
The Cassini space probe detected plumes on Saturn's moon Enceladus containing water, hydrogen, and organic molecules, with a pH of around 8 or 9, implying an underlying alkaline hydrothermal system.
General anesthetics appear to exert their main effect on mitochondria, and they can work on single-celled organisms like amoeba, suggesting a link between mitochondrial function and a fundamental aspect of consciousness.
All large, complex, visible life on Earth is composed of a single cell type, the eukaryotic cell.
The electrical field across a cell membrane, which is 5 nanometers thick and has a charge of 150-200 millivolts, is equivalent to 30 million volts per meter, comparable to a bolt of lightning.
The number of wet, rocky planets or moons in the Milky Way galaxy is estimated to be in the order of 20 to 40 billion.
Any wet, rocky planet will likely produce alkaline hydrothermal vents through the reaction of the common mineral olivine with water.