Marianna Marchini¹, Massimo Gandolfi¹, Lucia Maini¹, Lucia Raggetti², and Matteo Martelli²
Proceedings of the National Academy of Science of the USA (PNAS) 119 (14) e2119194119 Link to Article [https://doi.org/10.1073/pnas.2123171119]
¹Department of Chemistry “Giacomo Ciamician”, University of Bologna, 40126, Bologna, Italy
²Department of Philosophy and Communication Studies, University of Bologna, 40126, Bologna, Italy

Sulfate aerosols have long been implicated as a primary forcing agent of climate change and mass extinction in the aftermath of the end-Cretaceous Chicxulub bolide impact. However, uncertainty remains regarding the quantity, residence time, and degree to which impact-derived sulfur transited the This paper explores the chemistry of mercury as described in ancient alchemical literature. Alchemy’s focus on the knowledge and manipulation of natural substances is not so different from modern chemistry’s purposes. The great divide between the two is marked by the way of conceptualizing and recording their practices. Our interdisciplinary research group, composed of chemists and historians of science, has set off to explore the cold and hot extraction of mercury from cinnabar. The ancient written records have been perused in order to devise laboratory experiments that could shed light on the material reality behind the alchemical narratives and interpret textual details in a unique perspective. In this way, it became possible to translate the technical lore of ancient alchemy into the modern language of chemistry. Thanks to the replication of alchemical practices, chemistry can regain its centuries-long history that has fallen into oblivion.

S. N. Ferguson, A. R. Rhoden, M. R. Kirchoff
Journal of Geophysical Research (Planets) (in Press) Link to Article [https://doi.org/10.1029/2022JE007204]
Soutwest Research Institute Boulder, CO, USA
Published by arrangement with John Wiley & Sons

Recent dynamical modeling of the formation and evolution of the Saturnian satellites suggests that the ages of the mid-sized inner moons (Mimas, Enceladus, Tethys, Dione, and Rhea) could be as young as 100 Myr. This estimate is in contrast to most previous modeling and observational work that suggest an age more contemporaneous with the formation of Saturn 4.5 Ga ago. Given the heritage of using craters to constrain surface ages, we examine the impact craters of Dione using imagery from NASA’s Cassini ISS camera and analyze their size-frequency distributions (SFDs) to understand impactor populations. We survey four areas across different geologic terrains and compare our crater counts to standard outer solar system production functions. In addition to crater counts, we study several crater types such as elliptical and polygonal to further examine the bombardment source for the craters. We find evidence for a Saturn-specific planetocentric impactor source, as none of the standard production functions fit the data. We compare our Dione data with our work on Tethys and find similarly shaped SFDs between the satellites. However, Dione’s surface has been extensively modified to remove smaller craters (D ∼< 5km) and has been bombarded by larger impactors, creating more D ∼> 20 km on Dione than Tethys. In contrast, Tethys more generally represents an ancient unmodified surface within the Saturn system. More complete observations and assessment of the cratering records on the satellites of Uranus and Neptune’s moon Triton would enable better constraints on the bombardment history of the Saturn system.