A study published in the Planetary Science Journal on July 31, 2026, reveals evidence that liquid nitrogen may have recently flowed across Pluto’s Sputnik Planitia, marking the first indication of active liquid activity on the dwarf planet. The research, led by Dr. Alan Stern and Dr. Kelsi Singer, analyzes NASA’s 2015 New Horizons data to suggest that nitrogen ice melts beneath the glacier, rises through cracks, and temporarily darkens the surface.
New Horizons imagery from July 14, 2015, revealed dark, narrow streaks and broader patches along the glacier’s polygonal convection cells—features resembling Earth’s glacial melt patterns. Researchers propose that heat from Pluto’s interior melts nitrogen ice at the glacier’s base, creating liquid reservoirs that erupt upward through fractures, darkening the surface before refreezing.
The Discovery and Its Significance
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 Dr. Kelsi Singer, a principal scientist at the Southwest Research Institute (SwRI) and co-author of the study. The research team compared Pluto’s patterns to Greenland’s ice sheets, where liquid water darkens ice through basal melting. On Pluto, similar dark features suggest liquid nitrogen seeping from beneath the glacier, a process the study describes as “basal melting” driven by pressure and geothermal heat.
Pluto never stops surprising us,
said Dr. Alan Stern, principal investigator of the New Horizons mission. In addition to suggesting that liquids have recently expressed themselves on Pluto’s surface, this result also suggests a new kind of time-variable feature on Pluto.
Comparisons to Earth and Other Worlds
The research team used NASA’s Landsat 9 imagery of Greenland’s ice sheets to draw parallels between Earth and Pluto. On Earth, basal melting creates dark streaks by enlarging ice grains or depositing impurities. On Pluto, similar effects could arise from liquid nitrogen flows. Pluto has many unique terrains seen nowhere else in the solar system, and this area of Sputnik Planitia is one of them,
Singer added. Exploring that allows us to better understand how materials behave in environments that are difficult to produce on Earth.
Pluto’s atmospheric pressure and temperatures—averaging 37 kelvins, or about minus 236 degrees Celsius—rule out liquid nitrogen rain. Instead, the study posits that pressure-induced melting deep within the glacier’s nitrogen ice allows liquid to form. At depths where pressure lowers the melting point, geothermal heat from Pluto’s core could sustain this process. The authors propose that heat from Pluto’s interior melts nitrogen ice at the base of the glacier, where it collects in reservoirs before erupting upward through narrow fractures, a process they compare to volcanic dike systems on Earth. On Pluto, this mechanism could create liquid nitrogen reservoirs beneath the glacier, which then rise through narrow cracks.
Implications for Planetary Science
The discovery challenges assumptions about Pluto’s geological inactivity. Sputnik Planitia’s youth—less than a million years old—suggests recent activity, contradicting earlier theories of a static, frozen world. This is the first evidence of recently flowing liquid on Pluto,
noted NASA in a statement. The study’s authors stress that more high-resolution mapping and lab experiments are needed to confirm the mechanism. However, the findings open new avenues for understanding cryovolcanism and subsurface processes in the outer solar system.
For now, the study underscores Pluto’s dynamic nature, revealing a world where liquid nitrogen, not just ice or gas, shapes its surface. Pluto has many unique terrains seen nowhere else in the Solar System,
Singer said. This area of Sputnik Planitia is one of them.
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