Last week, Nix and Hydra transformed before our eyes from specks of light to bonafide moons. Today, NASA released a new set of images, bringing Pluto's oblong satellites into even better focus. The latest astonishing finds? Nix has a rosy glow and Hydra has craters.
The image on the left, captured by the New Horizons Ralph instrument from a distance of 164,000km is our very first colour shot of Nix. Colours have been enhanced, revealing a surprisingly reddish region on the rocky satellite that measures a mere 42km long and 35km across. According to NASA:
Although the overall surface colour of Nix is neutral grey in the image, the newfound region has a distinct red tint. Hints of a bull's-eye pattern lead scientists to speculate that the reddish region is a crater. "Additional compositional data has already been taken of Nix, but is not yet downlinked. It will tell us why this region is redder than its surroundings," said mission scientist Carly Howett, Southwest Research Institute, Boulder, Colorado. She added, "This observation is so tantalising, I'm finding it hard to be patient for more Nix data to be downlinked."
Meanwhile, the new image of Hydra, captured from a distance of 230,000km, also offers tantalising hints of complexity. There appear to be at least two large craters on Hydra's surface, and the moon's upper portion seems slightly darker than its lower half, perhaps suggesting a transition from a rockier to a more ice-rich composition.
"Before last week, Hydra was just a faint point of light, so it's a surreal experience to see it become an actual place, as we see its shape and spot recognisable features on its surface for the first time," mission science collaborator Ted Stryk said.
Remember, folks: This is just the beginning. We've downlinked a mere 2 per cent of the New Horizons data at this point, and it will take us another 16 months to gather the rest. I'm also finding it hard to be patient, but such is the nature of doing science over the solar system's worst dial-up connection.