August 5, 2026 — A new study led by Southwest Research Institute (SwRI) provides evidence that liquid nitrogen is rising to Pluto’s surface through cracks in the northern edge of the Sputnik Planitia, part of the massive heart-shaped glacier on the dwarf planet’s surface. This is the first evidence of liquid recently flowing on Pluto. The study is based on data from NASA’s New Horizons spacecraft and is led by SwRI Associate Vice President Dr. Alan Stern, the principal investigator of the New Horizons mission.
“Pluto never stops surprising us,” Lead Author Stern said, “and this new result certainly does that. 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.”
The Sputnik Planitia is a vast, frozen nitrogen glacier on Pluto, larger than Texas and Oklahoma combined. In 2015 and 2016, New Horizons images of the northernmost portions of this region revealed city-sized geologic convection cells on Sputnik Planitia separated by thin, dark linear and more diffuse, dark features. New analyses now indicate that these dark, linear and diffuse features appear to be occasionally and temporarily wetted, perhaps from time to time, by a liquid—most likely liquid nitrogen. This result has been published in the peer-reviewed Planetary Science Journal.
Pluto’s atmospheric and thermal conditions make liquid nitrogen rain physically impossible. Nonetheless, the surface patterns on northern Sputnik Planitia have been darkened in ways that resemble glacial features on Earth that have been wetted by water rain or the subsurface emergence of liquids to the surface.
The SwRI-led team of Pluto researchers compared the New Horizons images to NASA Landsat 9 imagery of locations on Earth, including the Greenland ice sheet. There, dark narrow surface features have been identified in areas where liquid water occurs on the ice and snow. The Sputnik Planitia images from New Horizons appear very similar, suggesting that subsurface liquids, specifically nitrogen, is rising and wetting Pluto’s nitrogen ice.
“The surface of Sputnik Planitia is quite young, probably less than one million years based on modeling of the surface overturn, and thus these features that we are looking at must have formed since then,” said SwRI Principal Scientist Dr. Kelsi Singer, one of the study’s co-authors. “Pluto has many unique terrains seen nowhere else in the solar system, and this area of Sputnik Planitia is one of them. 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.”
The new work provides the first evidence of recent liquid flows to the surface of Pluto. Earlier research, including some led by first author Stern, suggested ancient liquid flows, but the new work suggests there is currently or recently liquid nitrogen beneath the surface of the glacier.
Computer models led by Dr. Orkan Umurhan, senior research scientist at the SETI Institute, show that nitrogen ice at the base of Pluto’s kilometers-deep Sputnik glacier can melt, forming liquid nitrogen. Furthermore, these computer models revealed that this liquid can be transported upward to the surface through small conduits, similar to lava or geyser tubes, driven by buoyancy or pressure from below. The researchers found that once reaching the surface, the melted nitrogen can remain liquid long enough to flow downward on slopes on the Sputnik’s nitrogen glacier, wetting the icy surface and producing the observed dark features.
“I think the great significance of these findings, and the tantalizing picture that it promotes, is a great motivation and reason to further examine solid state nitrogen physics at very low temperatures,” Umurhan said. “Specifically, it’s important to examine the physics taking place in solid nitrogen materials under stress and strain, which can cause them to melt. These processes have never been studied in real detail in the laboratory.”
While no other regions of Pluto show evidence of basal flow over half of Pluto remains unmapped in high-resolution. The melting process and the liquid’s upward movement on Pluto could also potentially explain other events seen across the solar system, such as the geysers observed by NASA’s Voyager 2 on Neptune’s moon Triton. Further high-resolution mapping of Pluto and other Kuiper Belt planets is needed to determine if similar processes are occurring elsewhere in that region of the solar system.
The Johns Hopkins Applied Physics Laboratory in Laurel, Maryland, designed, built, and operates the New Horizons spacecraft and mission for NASA’s Science Mission Directorate. The Planetary Missions Program Office at Marshall Space Flight Center (MSFC) in Huntsville, Alabama, provides NASA oversight for New Horizons. Southwest Research Institute, based in San Antonio, directs the mission via Principal Investigator Dr. Alan Stern, who leads the science team, payload operations and science planning. New Horizons is part of the New Frontiers Program managed by NASA's MSFC.
The study “Evidence for possible N2 basal flow beneath Pluto's northern Sputnik Planitia,” was published this month in The Planetary Science Journal. DOI: https://doi.org/10.3847/PSJ/ae7e85
For more information, visit Planetary Science or contact Joanna Quintanilla, +1 210 522 2073, Communications Department, Southwest Research Institute, 6220 Culebra Road, San Antonio, TX 78238-5166.