In Greek mythology Charon was the boatman of the underworld, ferrying souls across the River Styx into the domain of Pluto. Fearsome of visage and manner, he offered no consolation to his passengers, only collecting their fares for what truly would be a one-way voyage.
Let’s meet his namesake.
This is Charon, Pluto’s largest satellite; New Horizons captured this image on 13 July during its flyby (though perhaps “fly-through” might be more appropriate) of the Plutonian system. At the time this photo was captured the spacecraft was slightly less than 500,000km from the rugged surface of Charon (for comparison our own Moon orbits Earth at roughly 400,000km), and the detail is impressive; we can see craters, mountain ranges and even an enormous canyon (estimated at 9km deep) along the upper right limb as seen in this image. Note the north polar region’s (top of the image) smooth appearance and dark coloration, this area of Charon has been un-officially named “Mordor”!
What I find most impressive is the overall shape of this body; it’s lumpy. If you’ll examine the photo in detail it looks similar to a shot of our Moon rising or setting, at which time the thickening atmosphere between our eyes and Luna tends to distort the image. The difference here is that there is no atmospheric filter in place; Charon really is that shape. Combining the odd form of this icy world with the impressive and varied geological features that we can see here (that canyon is rather “grand”, wouldn’t you say?), and it seems clear that this faraway object has had an interestingly dynamic geologic past.
Throughout our robotic explorations of the Solar System we’ve encountered surprises like these; it seems that however exotic the environment encountered there are processes at work. Geologic forces, chemical reactions, tidal stresses; there appear to be no static worlds out there even in the hinterlands of the Sun’s kingdom. Nature, it seems, abhors boredom above all else.
And this is only the beginning. As data continues to be beamed back from New Horizons over the coming months I expect we’ll have some questions answered and many more raised; after all, this is only the first reconnaissance of these cold, distant worlds.
Who knows what we might find?