Brand-new research suggests that Sputnik Planitia, the famous heart-shaped region of Pluto plays a pivotal role in regulating the atmospheric circulation across the distant dwarf planet. The surface of the vast plain is covered in frozen nitrogen. During the day a thin layer turns into vapor, and then freezes back at night. The cycle is what produces Pluto's winds, and new research has revealed they go in a surprising direction.
As reported in the Journal of Geophysical Research: Planets, the observations and models used by the team suggest that Pluto’s atmosphere, which is 100,000 times thinner than that of Earth’s own, moves in the opposite direction to the dwarf planet's rotation. The effect of this wind are the dark streaks across the northwestern regions of the dwarf planet.
“This highlights the fact that Pluto’s atmosphere and winds – even if the density of the atmosphere is very low – can impact the surface,” said lead author Tanguy Bertrand, an astrophysicist and planetary scientist at NASA’s Ames Research Center in California in a statement.
Sputnik Planitia is the left lobe of the Tombaugh Regio, where most of the nitrogen ice of Pluto is located. The ice sheet stretches for about 1,000 kilometers surrounded by high elevation structures. Models showed that the nitrogen ice turns into vapor in the north and freezes in the south, creating this atmospheric current of winds above 4 kilometers (2.5 miles) in altitude blowing to the west.
The dark streaks may be created by either the wind from the west transporting heat from the atmosphere to the ice, causing it to sublimate faster, and thus becoming less reflective, or the wind itself may be carrying dark materials that are deposited onto the ice.
“Sputnik Planitia may be as important for Pluto’s climate as the ocean is for Earth’s climate,” Bertrand said. “If you remove Sputnik Planitia – if you remove the heart of Pluto – you won’t have the same circulation,” Bertrand explained.
“Before New Horizons, everyone thought Pluto was going to be a netball – completely flat, almost no diversity,” Bertrand said. “But it’s completely different. It has a lot of different landscapes and we are trying to understand what’s going on there.”
It is a true testament that the flyby of New Horizons back in 2015 led to such a deep understanding of this world at the edge of the Solar System. We barely knew what it looked like then and now we have models for how winds shape its surface.