Pluto sports rounded and bizarrely textured mountains, informally named the Tartarus Dorsa, rise up along Pluto’s day-night terminator and show intricate but puzzling patterns of blue-gray ridges and reddish material in between. This viewi is rougnly 330 miles (530 kilometers) across, combines blue, red and infrared images and resolves details and colors on scales as small as 0.8 miles (1.3 kilometers). Credits: NASA/JHUAPL/SWRI
Okay. I am officially surprised. Pluto just got even MORE interesting than ever! Not only is it a colorful-looking icy world, but it’s got the weirdest snakeskin surface features I think I’ve ever seen. As soon as I saw this image, I thought immediately of frozen dunes.
What’s causing them? Good question.
Nobody knows.
Yet.
You can bet the New Horizons mission scientists are all over these images, trying to explain the kinds of tectonic forces or atmospheric activities that would form such fascinating features. You can see troughs cutting across snaky-looking frozen dune-like features, and some terrain that looks like giant footprints.
My best guess (and it’s only a guess) is that there’s something going on beneath the surface that is softening the ice from below. The frigid temps at the surface lock the softened features into place. Since we know nitrogen is escaping the surface, some of it may well also fall back to form terrain units of some kind. How that all works and how you prove it — well, that’s what the New Horizons planetary scientists are working to figure out!
Here’s the sharpest image to date of Pluto’s varied terrain. In this 75-mile (120-kilometer) section of the surface, textured terrain units surround two isolated ice mountains. Courtesy NASA/JHUAPL/SWRI
Really detailed images of the surface in Tombaugh Regio also show what looks like the cantaloupe terrain of Triton (at Neptune). This closer look at the smooth, bright surface of the informally named Sputnik Planum (within Tombaugh) shows that it is actually pockmarked by dense patterns of pits, low ridges and scalloped terrain. These could be some more of those dunes I talked about, made of bright ices that are especially susceptible to sublimation and formation of such corrugated ground.
Want to see more of Pluto’s weird terrain? Check out the NASA New Horizons website and the New Horizons mission site — they have the latest and greatest images and explanations about what’s happening out at this distant world.
A newly discovered mountain range lies near the southwestern margin of Pluto’s Tombaugh Regio (Tombaugh Region), situated between bright, icy plains and dark, heavily-cratered terrain. This image was acquired by New Horizons’ Long Range Reconnaissance Imager (LORRI) on July 14, 2015 from a distance of 48,000 miles (77,000 kilometers) and received on Earth on July 20. Features as small as a half-mile (1 kilometer) across are visible. Courtesy NASA/JHUAPL/SWRI
So, Pluto has a second set of mountains along one edge of Tombaugh Regio (the heart-shaped region). The planet continues to stun all of us with amazing views sent back by New Horizons, and the mountains are just the latest in a long string of discoveries to come. I can’t say I’m totally surprised to see them; I remember a geology teacher once saying where there’s one mountain range on a world, shaped by some kind of internal process, there’s bound to be another.
These mountains aren’t quite as high as the Norgay Montes, first seen on July 15th, but they’re still pretty spectacular-looking. They rise up to perhaps only a kilometer or so, but they look quite sharp, standing out in relief against the bright landscape. It looks like they may be younger than the surrounding landscape, but that’s just my guess. If so, then this surface is changing, indeed!
The thing that caught my eye after I checked out the mountains was that very interesting interface between the dark region and the brighter material that makes up Sputnik Planum (which is part of Tombaugh Regio). At first glance, I could tell that there’s been some filling in of craters by the white material. That’s another clue that the lighter-colored landscape is much younger than the darker regions. In fact, the team suspects the dark region is billions of years old, while the lighter landscape is less than a hundred million years old. That’s pretty young in planetary science terms, when you think about it. The solar system formed some 4.56 BILLION years ago, so this surface has only been around for a short time compared the age of the Sun and other worlds.
What Could Be Causing the Mountains on Pluto?
As I mentioned in my article of a few days back, called Pluto is Geologically Active, mountain-building processes here on Earth are driven by plate tectonics, which is itself driven by heat and motions beneath the planet’s crust. We don’t know yet what’s driving it on Pluto. The planet is just about 70 percent rock, so it might be that there’s activity in the interior related to decay of radioactive materials or some other process.
If that activity generates or is driven by heat, that would affect the icy surface, possibly causing mountains to form in some way, and ices to flow to create smoothed-over landscapes. Remember, the ices on Pluto are largely nitrogen and methane, and those can melt and/or sublimate at pretty low temperatures, so you wouldn’t need a lot of heat. I look forward to hearing a more nuanced and scientifically informed interpretation of the images from the New Horizons team.
There will be a science press conference on the 24th (you can watch at NASA.TV), and I suspect we’ll hear more about those mountains and the dichotomy between the dark and light regions of the planet. So, as I like to say, stay tuned!
Note: the spacecraft has gathered 50 gigabits of data, which it will be sending back over the ever-increasing distance between it and the Earth over the next 16 months. At times, the spacecraft will be returning various types of data, not all of it imaging. However, the team will be releasing images as often as they can, generally once a week or so. The best way to keep up with the news from New Horizons is to check out www.nasa.gov/newhorizons and/or pluto.jhuapl.edu — where you’ll find images, videos, and discussions of the latest Pluto scientific discoveries.
