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New Horizons spies the atmosphere of Pluto

David Dickinson, Correspondent
Jul 25, 2015, 5:09 UTC

Sen—The NASA New Horizons team released an amazing and iconic image at today’s press conference, showing the silhouette of Pluto inside the ring of its atmosphere as it was backlit by the Sun.

The image was taken on July 15 by the spacecraft’s LOng Range Reconnaissance Imager (LORRI) from a distance of 1.25 million miles (2 million kilometers), about five times the distance from the Earth to the Moon.

“My jaw was on the ground when I saw this first image of an alien atmosphere in the Kuiper Belt,” said principal investigator for New Horizons Alan Stern in today’s press release. “It reminds us that exploration brings us more than just incredible discoveries—it brings incredible beauty.”

But beyond just providing us with an amazing eye-candy view, the layering exposed in the image is valuable in terms of modeling the makeup and composition of the atmosphere as well.


New Horizons discovers flowing ices in the northern region of Pluto’s Sputnik Planum (Sputnik Plain), where swirl-shaped patterns of light and dark suggest that a surface layer of exotic ices has flowed around obstacles and into depressions, much like glaciers on Earth. Image credit: NASA/JHUAPL/SwRI

New Horizons flew by Pluto on July 14 at over 8 miles (14 kilometers) a second. The data retrieval pipeline from a distance of 32 astronomical units and increasing is so slow that we’ll be seeing new data from New Horizons well into 2016.

The team also released evidence for flowing methane ice and hydrocarbons on Pluto’s surface today, as well as some of the highest resolution imagery of Pluto's surface seen yet.


A stunning high-resolution image of Pluto by LORRI combined with color images from the Ralph instrument from just 280,000 miles (450,000 km) as the spacecraft was headed for closest approach. Image credit: NASA/Johns Hopkins University/APL/SWRI

And the first data from the occultation experiment from Pluto’s large moon Charon was released today as well. New Horizons flew briefly through the shadows of Pluto and Charon as it receded, conducting radio and spectroscopic occultation observations as it did so.

NASA’s flying SOFIA infrared telescope and amateur observations of stellar occultations by Pluto as seen from Earth will also supplement New Horizons data to help researchers model and understand its atmosphere.

“We’ve only seen surfaces like this on active worlds like Earth and Mars,” said mission co-investigator John Spencer in today’s press conference.

It’s a great time to be a planetary scientist for sure. More amazing results are on the way, as humanity continues to explore the brave new worlds of Pluto and its moons for months to come.

A simulated flyover of two regions on Pluto, northwestern Sputnik Planum (Sputnik Plain) and Hillary Montes (Hillary Mountains), informally named for Sir Edmund Hillary, one of the first two humans to reach the summit of Mount Everest in 1953. Credit: NASA/JHUAPL/SwRI