Sunset on Pluto [Slide Show]
The latest jaw-dropping images from NASA’s New Horizons mission to Pluto almost seem unreal, too vivid and majestic to exist anywhere outside of an artist’s imagination. Yet real they are, captured shortly after the spacecraft’s closest approach to the dwarf planet on July 14 and subsequently downlinked to Earth on September 13. Draped in shadow by the glancing light of a far-distant setting sun, a landscape of craggy ice mountains and flowing glaciers stretches to the horizon, blanketed by layers of haze and fog. As gorgeous as these new images are, the best may still be in store: Limits on data-transmission rates from the outskirts of the solar system ensure that more Plutonian pictures with higher resolution will be whispered back to Earth for many months to come
![Sunset on Pluto [Slide Show]](https://static.scientificamerican.com/sciam/cache/file/B0D99DCA-7648-4429-B30F8F3A89FACD73.jpg?w=590&h=393)
Sunset on Pluto [Slide Show]
- A WORLD OF ICE AND SHADOW Taken 15 minutes after closest approach, from a distance of 18,000 kilometers, this backlit image of Pluto's surface spans a shadow-crossed stretch of land some 1,250 kilometers wide. The smooth, icy expanse of the informally named Sputnik Planum can be seen on the middle right, flanked on the left by 3.5-kilometer-high mountains of water ice. The patchy, pockmarked terrain on the far right of the image is interspersed with glacial flows likely composed of frozen nitrogen. More than a dozen layers of delicate haze limn the world in tenuous halos of scattered light that extend over 100 kilometers from the surface. Credits: NASA/JHUAPL/SwRI
- FOG BANKS ON PLUTO: Zooming even farther in, to the right bottom corner of the previous image, the setting sun illuminates wispy tendrils of low-lying fog lacing the terrain, interspersed with long, fingerlike shadows cast by small hills and mountains. This image is 185 kilometers wide. Credits: NASA/JHUAPL/SwRI
- THE ACTIVE HEART OF PLUTO This composite image provides an overhead perspective of Sputnik Planum, which forms the smooth left lobe of Pluto’s now-famous “heart,” a bright feature stretching some 1,600 kilometers across the surface. The ridged, pitted uplands to the right of this flatland appears to be covered in bright nitrogen ice, perhaps swept there by winds blowing across the frigid plains below. The boxed region at the bottom of the image is the target of the next two images following this one. Credits: NASA/JHUAPL/SwRI
- ANHYDROUS HYDROLOGY The same region pictured in the preceding picture appears in new detail, thanks to a reprojection of the backlit, more oblique view from New Horizons’ latest imagery. Again, the red arrows indicate the glacial flow through a valley and the blue arrows reveal the flow front of the ice as it slowly spills into Sputnik Planum. Sunlight striking the plain evaporates ice, which may then fall as snow on the rugged uplands, building glaciers that then flow back to the lowlands, forming a loop akin to Earth’s hydrological cycle. Credits: NASA/JHUAPL/SwRI
