The mountains on Pluto – more than mountains we would call an ensemble that rises higher than any other on Earth outside the Himalayas – were revealed by reanalysis of images taken by the New Horizons spacecraft in 2015.
These peaks look like nothing else in the Solar System and could not have been formed from rock, planetary scientists believe, being instead composed of frozen ammonia, nitrogen, methane and water ice, however the their origins are little known.
Pluto is so small and far from the Sun that it was once thought to be completely frozen, however, the complex geology observed by New Horizons, including the absence of impact craters from parts of the dwarf planet, indicates that recent geological activity has reshaped some areas; Planetary scientists have spent the past seven years trying to make sense of the images they collected as New Horizons moved on and understand the forces that produced what we can see.
The most obvious feature of Pluto is its heart, technically known as Sputnik Planitiaan ice sheet approximately 1,050 kilometers (620 miles) in diameter, thought to fill an ancient impact basin, with its flanks comprising substantial hills made up of many small hillocks, plus a detailed study of Nature Communications reveals that the largest, to the southwest, is 7 kilometers (4.2 miles) high and about 225 kilometers (135 miles) wide.
The mountains on Pluto are more unusual than ever
The largest peak was called Piccard Monsbut it was in the dark when New Horizons snapped its more detailed images, as a result, the article focuses on another of the mountains on Pluto, Wright Mons, seen just before local sunset.
Doctor Kelsi Singer of the Southwest Research Institute and colleagues conclude that both are ice volcanoesbut rather than each forming in a single dramatic eruption, they likely represent many smaller explosions located close together, and although there are other lower mountains nearby, their volcanic state is less certain.
At 4 kilometers (2.49 miles) high and 150 kilometers (93.2 miles) in diameter, the second of the most important mountains on Pluto, Wright Mons, has roughly the same internal volume as Hawaii’s Mauna Loawhich is much larger than Everest but is far below sea level, however rather than being single peaks, Wright and Piccard may have formed from multiple eruptions so close together that the mountains merged to create the hilly pattern.
The absence of impact craters in the mountain area on Pluto indicates that it has resurfaced relatively recently, and if that were the case, Pluto would have retained enough heat to be able to drive such eruptions, likely from an internal ocean consisting of a muddy mixture of water, ammonia and other forms of antifreeze.
However, how this ocean survived, let alone the energy to produce such eruptions, remains an enigma, not least because Pluto certainly does not receive heat from the Sun, having a temperature of -230º C (-382º F) in surface.
Earth’s core is melted thanks to the heat generated by radioactive decay, but Pluto’s rocky core is so small it shouldn’t contain enough radioactive elements. The tidal interactions between Pluto and Charon would have provided a source of heat after the latter formed in a large impact, but this too is thought to have disappeared as the distance between the two objects increased.
However, the evidence of recent activity is too strong to deny; something created the energy to lift these mountains to ice Pluto.
A puzzling feature of Piccard and Wright to scientists were the gigantic depressions near their peaks, these appear to be calderas in volcanoes on Earth or Mars, but are much larger, even than the peaks that enclose them. Singer concluded that the gnarled “walls” of these craters represent the multiple peaks produced by a series of small eruptions, rather than the outline of a single cladera.
Although the two were considered candidates for ice volcanoes soon after the passage of New Horizon, it took so long to understand what we have of these mountains in part because we missed the opportunity to see Piccard clearly, plus the complex topography in this area proved to be a challenge to understand.
If you are attracted to science or technology, keep following us, so you don’t miss the latest news and news from all over the world!
#Mountains #Pluto #ice #7km #high