The Venus Lower Atmosphere Haze as a Depot for Desiccated Microbial Life

Abstract:

We propose a lifecycle that resolves the conundrum of how life can persist aloft in the Venusian temperature cloud deck for hundreds of millions to billions of years. We assume microbial-type life resides inside liquid droplets where it is protected from a fatal net loss of liquid to the atmosphere. Yet droplets inexorably grow over months to large enough sizes that are forced by gravity to settle downwards to hotter, uninhabitable atmosphere layers. Our new idea is that microbial life dries out as liquid droplets evaporate during settling, with the small desiccated “spores” halting at and partially populating the Venus atmosphere stagnant lower haze layer (33-48 km altitude). We thus call the Venusian lower haze layer a “depot” for desiccated microbial life. The spores eventually return to the cloud layer by upward diffusion caused by mixing induced by gravity waves, act as cloud condensation nuclei, and rehydrate for a continued life cycle.