NASA’s New Horizons spacecraft has sent an image of Pluto’s surface that reveals a vast, craterless plain that appears to be no more than 100 million years old, and is believed to be still in the process of forming. Located in north of Pluto’s icy mountains, the frozen region is informally named “Tombaugh Regio” (Tombaugh Region) after Clyde Tombaugh, who discovered Pluto in 1930.
“This terrain is not easy to explain,” said Jeff Moore, leader of the New Horizons Geology, Geophysics and Imaging Team (GGI) at NASA’s Ames Research Center in Moffett Field, California. “The discovery of vast, craterless, very young plains on Pluto exceeds all pre-flyby expectations.”
The icy plains region, similar to frozen mud cracks on Earth, has been named “Sputnik Planum” (Sputnik Plain) after the Earth’s first artificial satellite. The region has a broken surface of irregularly-shaped segments, roughly 20 km across, bordered by what appear to be shallow troughs. Some of these troughs have darker material within them, while others are traced by clumps of hills that appear to rise above the surrounding terrain.
Scientists believe the irregular shapes may be the result of the contraction of surface materials, similar to what happens when mud dries or they could be a product of convection, similar to wax rising in a lava lamp.
On Pluto, convection would occur within a surface layer of frozen carbon monoxide, methane and nitrogen, driven by the scant warmth of Pluto’s interior.
Pluto’s icy plains also display dark streaks that are a few miles long, which appear to be aligned in the same direction and may have been produced by winds blowing across the frozen surface, said NASA.
The Tuesday “heart of the heart” image was taken when New Horizons was 77,000 km from Pluto, and shows features as small as 1 km across. Mission scientists will learn more about these mysterious terrains from higher-resolution and stereo images that New Horizons will pull from its digital recorders and send back to Earth during the next year.