The Best Picture from Pluto So Far

The New Horizons spacecraft, which flew by Pluto in July, is slowly continuing to send back the images and data it took. The latest batch contains some of the most detailed close-up pictures of Pluto we have ever seen and they are fascinating!
Let’s take a look at the most intriguing new picture for a minute. We are seeing the greatest detail the spacecraft cameras were capable of. In a scene about 50 miles wide, we can make out details as small as half a city block. We see the shoreline of the Sputnik plains (part of the giant heart-shaped feature that caught everyone’s attention on the early pictures.)

The “rocks” that make up the mountains in the upper left are made of water – which is harder than rock at Pluto’s freezing temperatures. Some of these mountains are more than a mile and half high, with some of their sides bright with ice and others coated in a darker material that we are still learning about. This darker material may fall out of the sky, when ultraviolet light from the distant Sun causes chemical changes in Pluto’s thin atmosphere.

Notice how abruptly and cleanly the mountain end and give way to the softer, nitrogen-rich ice that makes up the Sputnik plains. In that ice, you can see huge but subtle cell-like structures. What makes up and drives this cell-like structure is still being debated by astronomers. Material in and around these cells may be moving up or down, like the cells you see when you boil miso soup. (If you've never boiled miso soup, ask a Japanese friend to tell you about it.) Cold nitrogen and methane ice might behave similarly when it is heated by the slightly warmer insides of Pluto and the faint heat of the Sun.
In an earlier photo, you can see some dark hills poking up at the boundary between cells, so this is very complicated terrain we are looking at. See the picture below. 
But just enjoy looking at the alien vista New Horizon’s cameras revealed. Pluto is not simple or boring!