Steven D. Vance | Search USGS

USGS2024

A survey of the severity of mental health symptoms in the planetary science community

There is a growing recognition of a mental health crisis within the academic and research communities. Members of the planetary science community have called for healthier work environments to improve mental well-being. As a preliminary step towards improving workplace culture, we sought to determine whether the broader mental health crisis extends to planetary science and to assess the severity of anxiety, depressive and stress symptoms. Our 2022 mental health survey of the planetary science community suggests that the severity of anxiety and depressive symptoms in the community is greater than in the general US population. Furthermore, anxiety and depressive symptoms are more severe for graduate students and postdoctoral researchers than any other career stage. Comparing groups within planetary science, we found that anxiety, depressive and/or stress symptoms appear greater among marginalized groups, such as women, people of colour and members of the LGBTQ+ community. A mental health problem is impacting the planetary science community. Improving well-being will promote enhanced research quality and productivity.

Nature Astronomy↗

USGS2023

Constraints on the composition and thermal structure of Ariel’s icy crust as inferred from its largest observed impact crater

The large graben-like troughs and smooth plains visible on the surface of Ariel are indicative of a period of high heat flow in the Uranian moon's past. High heat flows on icy moons like Ariel can also enable viscous flow that removes impact crater topography, a process called viscous relaxation. Here we use numerical modeling to investigate the conditions necessary to viscously relax Ariel's largest impact crater, Yangoor, which is 80 km in diameter and unusually shallow. If we assume that Ariel's crust consists of non-porous water ice, heat fluxes ≥60 mW m −2 are required to reduce an initially deep Yangoor-like crater to its current observed depth. Lower fluxes are required if a high-porosity (30%), low-conductivity surface layer several kilometers thick is assumed to exist, but in any case, fluxes in excess of 30 mW m −2 are necessary to substantially reduce Yangoor's topography. The inclusion of ammonia dihydrate has a negligible effect on our results despite decreasing the viscosity of Ariel's deep ice. Our results are consistent with previous inferences of high heat fluxes on Ariel, but exceed both expected radiogenic heat fluxes and known equilibrium tidal heat fluxes by an order of magnitude. If Yangoor's shallow depth is the result of tidal heating, then short-lived non-equilibrium tidal dissipation or some other source of energy is required. Notably, although our results do not require the presence of an ocean within Ariel, the thermal conditions necessary to viscously relax Yangoor also imply a relatively thin ice shell (∼10-km thick) if conductive heat transport is assumed.

Icarus↗