Researchers used New Horizons images to identify evidence that liquid nitrogen may have flowed from beneath Pluto’s famous heart-shaped glacier. Dark markings across part of Pluto’s enormous heart-shaped glacier may record something unexpected beneath its frozen surface: liquid nitrogen moving upward and briefly flowing across the ice. 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.” Sputnik Planitia, the western portion of Pluto’s famous heart-shaped region, is a vast glacier made largely of frozen nitrogen and is larger than Texas and Oklahoma combined. The models show that nitrogen ice deep beneath Sputnik Planitia, which is several kilometers thick, can melt at the base of the glacier and produce liquid nitrogen.