Artistic representation of the huge and slow impact on Pluto that led to the heart-shaped Sputnik ... [+]
Ever since NASA's New Horizons sent back the first-ever photos of Pluto in 2015, the dwarf planet's mysterious heart-shaped region has puzzled scientists.
New research suggests that Sputnik Planitia, also called Tombaugh Regio, is the result of a massive smash with another planetary body a little over 400 miles in diameter, roughly the size of Arizona from north to south.
Pluto was discovered in 1930 by Clyde Tombaugh while he worked at Lowell Observatory in Flagship, Arizona.
Ice Shell
Sputnik Planitia is a white basin measuring 750 by 1,250 miles near Pluto's equator that was discovered during the flyby. Although the dwarf planet is covered in an ice shell, that thins significantly at Sputnik Planitia, which scientists had thought contained a subsurface ocean insulated from the dwarf planet’s frozen conditions.
However, this new research—published this week in Nature Astronomy—also suggests that Pluto has no subsurface ocean.
Vast Majority
While the vast majority of Pluto's surface consists of methane ice and its derivatives covering a water-ice crust, “the Planitia is predominantly filled with nitrogen ice, which most likely accumulated quickly after the impact due to the lower altitude," said Harry Ballantyne, a research associate at the University of Bern in Switzerland, and the lead author of the study.
High-resolution view of Pluto Sputnik Planitia, captured by NASA’s New Horizons spacecraft.
Pluto’s Core
“Pluto’s core is so cold that the rocks remained very hard and did not melt despite the heat of the impact,” said Ballantyne. “Thanks to the angle of impact and the low velocity, the core of the impactor did not sink into Pluto’s core, but remained intact as a splat on it.”
It’s thought that the shape of Sputnik Planitia and its location at the equator is down to an oblique, rather than a head-on, collision with another planetary body.
Critical Window
“The formation of Sputnik Planitia provides a critical window into the earliest periods of Pluto’s history,” said Adeene Denton, a planetary scientist at the University of Arizona's Lunar and Planetary Laboratory, who co-authored the paper. “By expanding our investigation to include more unusual formation scenarios, we’ve learned some totally new possibilities for Pluto’s evolution, which could apply to other Kuiper Belt objects as well.”
Kuiper Belt
The Kuiper Belt is a disc-shaped region around the distant outer solar system beyond the orbit of Neptune that’s thought to be populated by icy objects and comets.
Pluto is 40 times further from the sun than Earth, with sunlight taking around 5.5 hours to reach it. It receives just 1/1,600th of the sunlight that Earth gets and temperatures can dip to -400F degrees Fahrenheit.
Wishing you clear skies and wide eyes.
