The difference in the depths of the water ice absorption features in the Nix and Hydra spectra raises new questions. Specifically, the science team is puzzling over why Nix and Hydra apparently have different ice textures on their surfaces, despite their similar sizes. Another mystery resulting from the Pluto flyby data is why Hydra’s surface reflectivity at visible wavelengths is higher than Nix’s – a New Horizons result published in March in the journalScience – even though Nix’s surface appears to be icier, implying higher reflectivity at visible wavelengths.