[meteorite-list] Pluto 'Wows' in Spectacular New Backlit Panorama

[Ron Baalke]

http://pluto.jhuapl.edu/News-Center/News-Article.php?page=20150917

Pluto 'Wows' in Spectacular New Backlit Panorama
September 17, 2015

The latest images from NASA's New Horizons spacecraft have scientists 
stunned - not only for their breathtaking views of Pluto's majestic icy 
mountains, streams of frozen nitrogen and haunting low-lying hazes, but 
also for their strangely familiar, arctic look.

This new view of Pluto's crescent - taken by New Horizons' wide-angle 
Ralph/Multispectral Visual Imaging Camera (MVIC) on July 14 and downlinked 
to Earth on Sept. 13 - offers an oblique look across Plutonian landscapes 
with dramatic backlighting from the sun. It spectacularly highlights Pluto's 
varied terrains and extended atmosphere. The scene measures 780 miles 
(1,250 kilometers) across.

"This image really makes you feel you are there, at Pluto, surveying the 
landscape for yourself," said New Horizons Principal Investigator Alan 
Stern, of the Southwest Research Institute, Boulder, Colorado. "But this 
image is also a scientific bonanza, revealing new details about Pluto's 
atmosphere, mountains, glaciers and plains."

Owing to its favorable backlighting and high resolution, this MVIC image 
also reveals new details of hazes throughout Pluto's tenuous but extended 
nitrogen atmosphere. The image shows more than a dozen thin haze layers 
extending from near the ground to at least 60 miles (100 kilometers) above 
the surface. In addition, the image reveals at least one bank of fog-like, 
low-lying haze illuminated by the setting sun against Pluto's dark side, 
raked by shadows from nearby mountains.

"In addition to being visually stunning, these low-lying hazes hint at 
the weather changing from day to day on Pluto, just like it does here 
on Earth," said Will Grundy, lead of the New Horizons Composition team 
from Lowell Observatory, Flagstaff, Arizona.

Combined with other recently downloaded pictures, this new image also 
provides evidence for a remarkably Earth-like "hydrological" cycle on 
Pluto - but involving soft and exotic ices, including nitrogen, rather 
than water ice.

Bright areas east of the vast icy plain informally named Sputnik Planum 
appear to have been blanketed by these ices, which may have evaporated 
from the surface of Sputnik and then been redeposited to the east. The 
new Ralph imager panorama also reveals glaciers flowing back into Sputnik 
Planum from this blanketed region; these features are similar to the frozen 
streams on the margins of ice caps on Greenland and Antarctica.

"We did not expect to find hints of a nitrogen-based glacial cycle on 
Pluto operating in the frigid conditions of the outer solar system," said 
Alan Howard, a member of the mission's Geology, Geophysics and Imaging 
team from the University of Virginia, Charlottesville. "Driven by dim 
sunlight, this would be directly comparable to the hydrological cycle 
that feeds ice caps on Earth, where water is evaporated from the oceans, 
falls as snow, and returns to the seas through glacial flow."

"Pluto is surprisingly Earth-like in this regard,' added Stern, "and no 
one predicted it."

[Image]
Just 15 minutes after its closest approach to Pluto on July 14, 2015, 
NASA's New Horizons spacecraft looked back toward the sun and captured 
this near-sunset view of the rugged, icy mountains and flat ice plains 
extending to Pluto's horizon.

[Image] 
Just 15 minutes after its closest approach to Pluto on July 14, 2015, 
NASA's New Horizons spacecraft looked back toward the sun and captured 
a near-sunset view of the rugged, icy mountains and flat ice plains extending 
to Pluto's horizon.

[Image] 
In this small section of the larger crescent image of Pluto, the setting 
sun illuminates a fog or near-surface haze, which is cut by the parallel 
shadows of many local hills and small mountains.

[Image]
Sputnik Planum is the informal name of the smooth, light-bulb shaped region 
on the left of this composite of several New Horizons images of Pluto.

[Image] 
Ice (probably frozen nitrogen) that appears to have accumulated on the 
uplands on the right side of this 390-mile (630-kilometer) wide image 
is draining from Pluto’s mountains onto the informally named Sputnik Planum.

[Image] 
This image covers the same region as the image above, but is re-projected 
from the oblique, backlit view shown in the new crescent image of Pluto.