Pluto Glacial Heart Shows Evidence of Recent Liquid Nitrogen Flow

New Study Reveals Evidence of Recent Liquid Nitrogen Flow on Pluto

The findings are based on a fresh analysis of images and data captured during NASA’s New Horizons spacecraft flyby of Pluto on July 14, 2015. Researchers focused on the northern and eastern portions of Sputnik Planitia, a vast frozen nitrogen glacier situated on the western side of Pluto’s famous heart-shaped feature. The glacier spans an area larger than Texas and Oklahoma combined.

Pluto never stops surprising us, said Phys.org, lead author of the study and Associate Vice President at the Southwest Research Institute (SwRI), where he also serves as principal investigator for the New Horizons mission. In addition to suggesting that liquids have recently expressed themselves on Pluto's surface, it also suggests a new kind of time-variable feature on Pluto.

Cracks, Convection Cells, and Buried Melt

When New Horizons flew past the dwarf planet, its cameras detected thin, dark linear markings and broader dark surface features located between massive convection cells across Sputnik Planitia. Scientists initially considered several potential explanations for these patterns, including ancient geological activity.

However, the new investigation points toward ongoing or recent subsurface activity. Because Pluto’s thin atmosphere makes liquid nitrogen rainfall physically impossible, researchers concluded that the nitrogen must be originating from beneath the glacier. According to the study, nitrogen ice at the base of the kilometers-deep glacier can melt under pressure and travel upward through cracks and conduits before refreezing on the surface.

NASA’s New Horizons Reveals Geologically Active World on Pluto

The surface of Sputnik Planitia is quite young, probably less than 1 million years old based on modeling of the surface overturn, and thus these features that we are looking at must have formed since then, explained SwRI Principal Scientist Phys.org, a co-author of the research.

Computer simulations led by Dr. Orkan Umurhan, a senior research scientist at the SETI Institute, demonstrated that nitrogen ice under stress and strain at the base of the glacier can indeed melt. The resulting liquid can then percolate through the glacial ice, wetting the surface and creating the dark streaks observed by spacecraft cameras.

Implications for Planetary Science and Solid-State Physics

The discovery challenges long-standing assumptions that distant icy worlds at the edge of the solar system are geologically dead and permanently frozen. Instead, features within Sputnik Planitia indicate that internal processes may still be operating on geological timescales.

Researchers note that studying these phenomena provides rare insights into material behavior under extreme conditions. Pluto has many unique terrains seen nowhere else in the solar system, and this area of Sputnik Planitia is one of them, Singer stated. Its surface provides a different set of conditions compared to what we are used to on Earth, and exploring that allows us to better understand how materials behave in environments that are difficult to produce on Earth.

Co-author Umurhan emphasized that the findings offer a strong reason to further examine solid-state nitrogen physics at very low temperatures. Understanding how solid nitrogen materials react under extreme stress and strain to cause melting could also shed light on other icy bodies throughout the solar system, such as Triton or Europa.