File:Pluto's Icy Plains Captured in Highest-Resolution Views from New Horizons.jpg

English: NASA’s New Horizons spacecraft continues to transmit the sharpest views of Pluto that it obtained (and recorded) during its flyby of the distant planet on July 14, 2015.

The newest image, returned on Dec. 24, 2015, extends New Horizons’ highest-resolution swath of Pluto to the very center of the informally named Sputnik Planum, and nearly completes the set of highest-resolution images taken by New Horizons last July.

The pictures are part of a sequence taken near New Horizons’ closest approach to Pluto, with resolutions of about 250-280 feet (77-85 meters) per pixel – revealing features smaller than half a city block on Pluto’s surface. The images shown here form a strip 50 miles (80 kilometers) wide and more than 400 miles (700 kilometers) long, trending from the northwestern shoreline of Sputnik Planum and out across its icy plains. The images illustrate the polygonal or cellular pattern of the plains, which are thought to result from the convective churning of a deep layer solid, but mobile, nitrogen ice.

The surface of Sputnik Planum appears darker toward the shore (at top), possibly implying a change in composition or surface texture. The occasional raised, darker blocks at the cell edges are probably dirty water “icebergs” floating in denser solid nitrogen.

The pictures were taken with the telescopic Long Range Reconnaissance Imager (LORRI) aboard New Horizons, from a range of approximately 10,000 miles (17,000 kilometers) over a timespan of about a minute centered on 11:36 UT on July 14 – just about 15 minutes before New Horizons’ closest approach to Pluto. The images are six times better than the resolution of the global Pluto map New Horizons obtained, and five times better than the best images of Pluto’s cousin Triton, Neptune’s large moon, obtained by Voyager 2 in 1989.