Was Venus ever habitable?

Tereza Constantinou Cambridge Fluids Network - fluids-related seminars 25 October 2023 1:15pm The Hoyle Lecture Theatre + Zoom Venus' geodynamic and climatic history is uncertain, particularly whether the surface ever hosted liquid water and habitable conditions. Large D/H ratios measured from Pioneer Venus could indicate the existence of a large water reservoir on Venus. However, it is unclear whether this water ever existed in a liquid form on the surface, allowing for habitable conditions, or if it solely existed as gas or clouds in the atmosphere. The presence of surface water on Venus is still unknown due to a large global volcanic surfacing event 0.2-3 billion years ago that has obscured much of its history. Venus may now be uninhabitable, but in the lead-up to its current hot and dry state, two climatic paths have been proposed, the "dry Venus" scenario: slow magma ocean solidification, early desiccation, hellish environment & the "temperate Venus" scenario: habitable past, with a lasting temperate climate, shallow oceans and plate tectonics. In this talk I will present how we constrain Venus' climatic past and whether the planet had surface oceans, with a direct observational test that speaks to Venus' climate past.