Charon Looks A Lot Like An Old Friend
Despite earlier indications that we'd have to wait until Friday for the tantalizing data coming down from New Horizons' close approach phase, the team did tease us with a new LORRI frame via Twitter. Like Wednesday's image, it brings out stunning details in a previously imaged region, but this time Charon is the target:
At left, the surprising image of Charon released on Wednesday afternoon by the New Horizons team. At right, a magnified portion captured by the LORRI imager as the spacecraft drew closer to the moon. Credit: NASA/JHUAPL/SWRI
Pluto's largest moon had already shocked the team and the audience on Wednesday by displaying a smooth, diverse face that had clearly undergone some form of resurfacing, in contrast to the ancient, impact-battered surface that was generally expected. With its noticeable differences in albedo (brightness) and large, flat expanses of terrain, it looked, superficially at least, like Earth's moon.
The enhanced region released today only bolsters the resemblance. Visible grooves in the surface have the appearance of rilles, a feature first noticed on our moon, but also present elsewhere in the solar system. There are many possible explanations and no particular consensus about what forms these long, curvy channels, and their newfound presence on Charon (or at least something resembling them) might make such a consensus even harder to reach.
But you could be forgiven for missing the rille-like features if your eye was first caught by the bizarre feature in the upper left corner of the high resolution frame. Informally dubbed the "mountain in a moat" around the internet, the steep depression with a large protrusion filling it almost entirely has no familiar analogue elsewhere in our solar system, at least that anyone has yet found. In many high velocity impacts, rebounding molten material will flood to the center of the resulting crater and create a peak, but this looks nothing like that.
At a briefing tomorrow at 1:00 pm EDT, the team will release what promises to be another round of amazing images and results.