Ancient Venus Conference
The conference on Ancient Venus, the first of the series of meetings to be held as part of the Lunar and Planetary Institute’s (LPI’s) Venus Science Initiative, was held on July 25–27, 2022. Out of continuing caution about the COVID pandemic, the meeting was entirely virtual. The meeting was organized into sessions of related talks followed by question/answer periods for all the session’s speakers — this format allowed for questions to multiple speakers and for speakers to question each other and explore topics in more detail.
The purpose of the Venus Science Initiative is to summarize and consolidate the community’s understanding of Venus and to explore ways that the upcoming spacecraft missions can enhance and enlarge that understanding. Ancient Venus thus focused on the formation and environment of ancient Venus and the transition from that prior state. Sessions in the conference focused on the source(s) and evolution of Venus’ atmosphere, the hypotheses that Venus might once have had an ocean of liquid water, Venus’ tesserae as possible remnants of ancient primordial crust, and dynamics of Venus’ interior and how its evolution affected the surface environment and atmosphere.
The atmosphere sessions focused on chemical clues, isotopic and elemental, about Venus’ ancient past. There was a strong emphasis on noble gas elements, for which abundances are unaffected by chemical processes, and isotope ratios can be characteristic of their sources in the early solar system. Major unanswered questions center on xenon — whether its abundance has been strongly affected by atmospheric loss, and whether its isotope ratios are similar to those of Earth, Mars, or other reservoirs in the solar system.
The session about possible ancient oceans presented several climate models, in which oceans might or might not have been stable. A particular issue is coupling between the solid planet’s rotation rate, the rotation of its atmosphere, and how clouds in these models affect solar insolation.
Sessions on tectonics focused on the nature of tesserae terrain, and the inferred transition(s) from some earlier to the present tectonic regime. Generally, it was inferred that Venus once supported mobile-lid tectonics (perhaps not like terrestrial plate tectonics), with most of the presentations centered on the nature and timing of the transition to the current stagnant lid condition.
The Venus Science Initiative will include three more conferences in the coming years. Venus Surface and Atmosphere will be held January 30–February 1, 2023, at the LPI in Houston, Texas (https://www.hou.usra.edu/meetings/venussurface2023/). Venus as a System will be held in November 2023, likely in conjunction with the VEXAG 21 meeting. And Venus-Like Planets and Exoplanets will be held in May 2024, at a site to be determined.
For more information about the conference, including links to the program and abstracts, visit https://www.hou.usra.edu/meetings/ancientvenus2022/.
— Text provided by A. H. Treiman