Before New Horizons reached Pluto in July, most of us pictured the planet as a drab, grey rock that used to be considered the solar system’s ninth planet. NASA’s New Horizons spacecraft revealed a stunning world with relatively smooth plains, mountain ranges and craters dotting its landscape.
Multiple layers of atmospheric haze are responsible for this beautiful picture released earlier this month.
Principal Investigator Alan Stern touches on one of the biggest surprises from New Horizons’ close encounter with the Pluto system. “The Pluto system surprised us in many ways, most notably teaching us that small planets can remain active billions of years after their formation,” says Stern.
Some of this activity appears to have happened fairly recently. The most obvious indication of recent activity is Sputnik Planum (seen below). It’s smooth surface stands in stark contrast to the cratered surface seen below it.
While the high-resolution images of Pluto steal the show, New Horizons also captured interesting data of Pluto’s largest moon Charon and its smaller ones – Nix and Hydra. Charon’s surface might not be as diverse as Pluto’s, but it does show evidence of major resurfacing. Its darker north pole region also stands out and remains a mystery for now.
Vast canyons stretch for more than 1,000 miles across the entire face of Charon. Scientists believe the canyons may even stretch across the entire planet’s surface. This massive canyon system is four times longer than the Grand Canyon and twice as deep in spots. It hints at incredible geological upheaval at some point in Charon’s past.
The images of Nix and Hydra are nowhere near as good as Pluto and Charon. But, New Horizons did measure the two satellites size for the first time. It also measured the pair’s surface reflectivity, which held another surprise. They were higher than Charon’s.
Pluto’s past is good news for New Horizons future
It’s safe to say Pluto blew past everyone’s wildest expectations. One of the farthest worlds in our solar system is shockingly diverse. What shaped Pluto’s terrain? It’s a question scientists will tackle for years to come. Scientists eagerly await even more data from New Horizons. There’s still about a year left of data downlinking as New Horizons continues to venture towards the Kuiper Belt.
The diverse world of Pluto is great news for a possible extension of the New Horizons mission. A Kuiper Belt object (KBO) is being eyed if an extension is approved. In their study, the scientists write, “that other small planets of the Kuiper Belt, such as Eris, Makemake, and Haumea, could express similarly complex histories that rival those of terrestrial planets.”
Jim Green, director of planetary science at NASA Headquarters in Washington, says it best. “New Horizons is not only writing the textbook on the Pluto system, it’s serving to inspire current and future generations to keep exploring – to keep searching for what’s beyond the next hill.”