In its final farewell to Pluto, New Horizons has captured an incredible image of the dwarf planet bathed in a mysterious halo.
The shot was taken just seven hours after the probe’s closest approach and shows peculiar layers of haze in the dwarf planet’s atmosphere.
‘This is our equivalent on New Horizons of the Apollo 11 Earthrise,’ said New Horizons’ Alan Stern, adding that the image confirms the probe had succeeded in its mission.
Nasa today also released an image of exotic ice across the dwarf planet’s surface, revealing signs of recent geologic activity – something scientists hoped to find but didn’t expect.
‘We’ve only seen surfaces like this on active worlds like Earth and Mars,’ said mission co-investigator John Spencer of SwRI. ‘I’m really smiling.’
Farewell Pluto! Backlit by the sun, Pluto’s atmosphere rings its silhouette like a luminous halo in this image taken by NASA’s New Horizons spacecraft around midnight EDT on July 15. This global portrait of the atmosphere was captured when the spacecraft was about 1.25 million miles (2 millionkm) from Pluto and shows structures as small as 12 miles across
The close-up images of ice show fascinating detail within the Texas-sized plain – named Sputnik Planum – that lies within the western half of Pluto’s heart-shaped region, known as Tombaugh Regio.
There, a sheet of ice clearly appears to have flowes, and may still be flowing, in a manner similar to glaciers on Earth.
The parting shot of Pluto, meanwhile, shows two distinct layers of haze –one about 50 miles (80km) above the surface and the other at an altitude of about 30 miles (50km).
‘My jaw was on the ground when I saw this first image of an alien atmosphere in the Kuiper Belt,’ said New Horizons Principal Investigator Alan Stern of the Southwest Research Institute (SwRI), Boulder, Colorado.
‘It reminds us that exploration brings us more than just incredible discoveries – it brings incredible beauty.’
Studying Pluto’s atmosphere provides clues as to what’s happening below.
New images from New Horizons have revealed exotic ices on the dwarf planet. Scroll left to see an annotated version of various features
Four images from New Horizons’ Long Range Reconnaissance Imager were combined with colour data from the Ralph instrument to create this enhanced colour global view of Pluto. (The lower right edge of Pluto in this view currently lacks high-resolution colour coverage). The images, taken when the spacecraft was 280,000 miles (450,000km) away, show features as small as 1.4 miles (2.2km)
NEW HORIZONS: THE STORY SO FAR
New Horizons launched in January 19, 2006 in the highest-velocity escape from Earth ever attempted.
After three billion mile journey that took almost a decade, the probe last week arrived at Pluto.
It flew past the dwarf planet on the 14th of July capturing history’s first close look at the distant world.
Within two days of its flyby it sent back stunning images of icy mountain ranges on the planet for the first time.
Since then, it has revealed remarkable, high-definition images and a 3D flyover of Pluto showing the dwarf planet’s vast icy landscape of the dwarf planet.
Images its moons Nix, Charon and Hydra, have also been released, with Nix being describes as a ‘red jellybean’ moon.
Nasa says the best images are yet to come, and it will be releasing them over a period of 16 months as the probe sends data back to Earth.
‘The hazes detected in this image are a key element in creating the complex hydrocarbon compounds that give Pluto’s surface its reddish hue,’ said Michael Summers, a New Horizons co-investigator.
Models suggest that the hazes form when ultraviolet sunlight breaks apart methane gas, a simple hydrocarbon known to reside throughout Pluto’s atmosphere.
The breakdown of methane triggers the buildup of more complex hydrocarbon gases, such as ethylene and acetylene, which were also discovered at Pluto by New Horizons.
As these hydrocarbons fall to the lower, colder parts of the atmosphere, they condense as ice particles, forming the hazes.
Ultraviolent sunlight chemically converts hazes into tholins, the dark hydrocarbons that colour Pluto’s surface.
Meanwhile, New Horizons scientists are using enhanced colour images to detect differences in the composition and texture of Pluto’s surface.
When close-up images are combined with colour data from the Ralph instrument, they paint a new and surprising portrait of Pluto in which a global pattern of zones vary by latitude.
The darkest terrains appear at the equator, mid-tones are the norm at mid-latitudes, and a brighter icy expanse dominates the north polar region.
The New Horizons science team is interpreting this pattern to be the result of seasonal transport of ices from equator to pole.
The ‘heart of the heart,’ Sputnik Planum, is suggestive of a reservoir of ices. The two bluish-white ‘lobes’ that extend to the southwest and northeast of the ‘heart’ may represent exotic ices being transported away from Sputnik Planum.
Alongside this, new compositional data from New Horizons’ Ralph instrument indicate that the center of Sputnik Planum is rich in nitrogen, carbon monoxide, and methane ices.
This image of the southern region of Sputnik Planum illustrates its complexity, including the polygonal shapes of Pluto’s icy plains, its two mountain ranges, and a region where it appears that ancient, heavily-cratered terrain has been invaded by much newer icy deposits. The large crater highlighted in the image is about 30 miles (50km) wide, approximately the size of the greater Washington, DC area
Backlit by the sun, Pluto’s atmosphere rings its silhouette in this image from NASA’s New Horizons spacecraft. Hydrocarbon hazes in the atmosphere, extending as high as 80 miles (130 kilometers) above the surface, are seen for the first time in this image, which was taken on July 14. New Horizons’ Long Range Reconnaissance Imager captured this view about seven hours after the craft’s closest approach
‘At Pluto’s temperatures of minus-390 degrees Fahrenheit, these ices can flow like a glacier,’ said Bill McKinnon, of Washington University in St. Louis, deputy leader of the New Horizons Geology, Geophysics and Imaging team.
In the southernmost region of the heart, adjacent to the dark equatorial region, it appears that ancient, heavily-cratered terrain has been invaded by much newer icy deposits.
Earlier this week, astronomers discovered a second, impressive mountain range on Pluto’s icy surface.
New Horizons spotted the new, apparently less lofty series of mountains on the lower-left edge of Pluto’s best known feature, the bright, heart-shaped region named Tombaugh Regio.
These newly-discovered frozen peaks are believed to be one-half mile to one mile (1 to 1.5km) high, about the same height as the US’ Appalachian Mountains.
The Norgay Montes (Norgay Mountains) discovered by New Horizons on July 15 more closely approximate the height of the taller Rocky Mountains.
The new range is just west of the region within Pluto’s heart called Sputnik Planum (Sputnik Plain). The peaks lie some 68 miles (110 kilometers) northwest of Norgay Montes.