A new analysis of images from NASA's New Horizons spacecraft suggests that liquid nitrogen may be rising through cracks to Pluto's surface.
The evidence is found near the northern edge of Sputnik Planitia, the vast frozen nitrogen glacier that forms the western side of Pluto's bright, heart-shaped region.
Dark lines and softer dark patches in the 2015 images may have been temporarily wetted by liquid, most likely liquid nitrogen. Because Pluto's atmosphere and temperatures make nitrogen rain physically impossible, the researchers say the liquid may be coming from beneath the glacier.
NASA described this as the first evidence of recently flowing liquid on Pluto. The research was published in the Planetary Science Journal on July 31, and the page notes that the exact timing and amount of any flow remain unknown.
