Researchers announced Monday that the mountains found on topographic maps of Pluto’s hemisphere may actually be ice volcanoes.
Images of two mountains measuring 100 miles across and several miles high were taken by the New Horizons probe in July, and were initially assumed to be mountains. However, researchers now believe that these may be the first ice volcanoes spotted in the outer solar system. According to New Horizons team member Oliver White, who spoke this week at an American Astronomical Society Division for Planetary Sciences meeting, the structures may have been formed in an unusual way. Still, he admitted to “having difficulty unseeing volcanoes” when looking at the structures.
“As someone who did his Ph.D. on volcanic morphology, when you see a big mountain with a hole in the top it generally points to one thing,” White said. “While it’s crazy, it’s still the least crazy idea we can think of.”
New Horizons principal investigator Alan Stern added that the mountains – or volcanoes – are “truly amazing,” and nothing like what NASA had seen before. “It’s like something on a terrestrial planet,” he observed.
Meanwhile, New Horizons’ data also revealed information on Pluto’s nitrogen atmosphere, suggesting that it is colder than believed on earlier observations made on Earth. “We thought the exobase, the top of the atmosphere, was seven to eight times larger than Pluto,” said Southwest Research Institute deputy project scientist Leslie Young. “And now, we know (it is) only about two and a half times larger than Pluto. Still significant, still an extended atmosphere, but much more compact.”
Young also related that NASA had thought the escape rate was large enough for the planet to lose about a half-mile of ice over four and a half billion years. With the new rate, it’s something like half a foot. “We still might have ices … moving around on the surface, but the atmosphere has huge implications for the history of the geology of Pluto as well,” she continued.