Pluto’s weird, icy plains likely caused by Manhattan-sized asteroid

The vast and craterless ice plain discovered on Pluto by NASA’s New Horizons spacecraft this summer was likely created by a massive space rock approximately the same size as Manhattan, researchers involved with the US space agency’s mission have revealed.

The icy region, unofficially known as Sputnik Planum, is “a large impact basin,” New Horizons lead investigator Alan Stern of the Southwest Research Institute (SwRI) in Colorado reportedly said earlier this week at the 227th meeting of American Astronomical Society (AAS).

According to Gizmodo, Stern was presenting the science data collected by New Horizons during its 2015 visit to the Pluto system when he presented the latest theories on how the dwarf planet’s smooth, frozen expanses might have originally formed. He explained that Sputnik Planum was likely the result of an asteroid roughly 6.2 miles (10 km) in size.

A space rock that large would have been comparable in size to Manhattan, the website noted, and it could have collided with Pluto’s surface several million or even billions of years ago. In fact, it is distinctly possible that the plain was located elsewhere when the impact took place.

Frozen terrain likely shifted position following collision

Currently, Sputnik Planum is located near Pluto’s equator, in the area of the dwarf planet known as Tombaugh Regio—but it might not have always been there. As Stern reported during the AAS conference, the size and volume of the plain is such that the “negative mass anomaly” caused by the Manhattan-sized asteroid’s impact caused it to shift positions to its current location.

Such an event, he added, would be similar in nature to the polar wander observed by geologists here on Earth, and the unusual jagged mountain ranges surrounding it could have also been made by the impact of the massive space rock, Gizmodo said. The lack of craters and the evidence of glacial flows indicate that Sputnik Planum is a relatively young, geologically active region.

These new findings are just scratching the surface of what scientists may learn about Pluto and its moons, as New Horizons collected such a massive amount of data that it will be downlinking information at least through the summer. Meanwhile, the probe is continuing outwards towards the Kuiper Belt, where it is preparing to study a new target starting in 2019.

“Three quarters of (the recorded data) is still up on the spacecraft, and no one has seen it,” Stern said at the AAS meeting, according to CBS News. “So we expect to be having presents continue to rain down throughout most of this year, probably into October or November.”

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Feature Image: NASA/JHUAPL/SWRI