Overview
- A Southwest Research Institute–led study published this week reanalyzed 2015 New Horizons imagery and reports dark, linear and diffuse patterns along the northern edge of Sputnik Planitia that appear to have been wetted recently.
- Lead author Alan Stern and co-authors argue those wetted patterns most plausibly come from liquid nitrogen rising from beneath the glacier rather than from atmospheric precipitation because Pluto’s atmosphere is too thin and cold for nitrogen rain.
- Modeling by Orkan Umurhan and colleagues shows that pressure and heat at the base of the kilometers-deep nitrogen glacier can cause basal melting and drive buoyant liquid nitrogen up small conduits to reach the surface and flow briefly down slopes.
- The surface of Sputnik Planitia is modeled as geologically young (likely under one million years), so any basal flow responsible for the dark features would be recent on that timescale and mark a new type of time-variable process on Pluto.
- Authors stress the result is inferential and not a direct observation, and they call for laboratory experiments on solid nitrogen, wider high-resolution mapping of Pluto, and future missions to test whether similar basal processes operate on other icy worlds such as Triton.