The icy plain of Sputnik Planum, located in Pluto’s heart-shaped Tombaugh Reggio, is criss-crossed with troughs that divide the plain into polygons. The current interpretation of these features is that they are the result of thermal convection. As with Rayleigh-Benard convection cells on Earth, the interior of the polygons is formed by the upwelling of warmer, buoyant material, and the troughs between cells mark locations where cooled material convects back into the mantle. On Pluto, these cells consist of nitrogen ice (and occasional water ice like the dirty black chunk seen in the upper right photo) that slowly rises and sinks from the planet’s surface, constantly refreshing the surface features. This would explain why Sputnik Planum is missing evidence of typical older features like impact craters. (Image credits: NASA/JHU APL/SwRI)
Join FYFD all this week for a look at fluid dynamics and planetary science on Pluto! Check out the previous posts here.