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What Do We Know About the Mountains of Pluto?

Leonard Kelley holds a bachelor's in physics with a minor in mathematics. He loves the academic world and strives to constantly explore it.

Tombaugh Regio

One of the first major surface features New Horizons uncovered during its Pluto flyby was mountains. Located along the western edge of the heart-shape feature on Pluto known as the Tombaugh Regio, the mountains offered some tantalizing and shocking clues about what goes on geologically with this dwarf planet.

Some of them are higher than the Himilayas at over 11,000 feet and instead of being made of rock are composed of water ice. The images showed no signs of impact craters, leading scientists to think that the mountains are young, probably no more than 100 million years old. As to what could have allowed much of Pluto to have this youthful appearance is still hotly contested, but the best theory was radiological decay causing the interior to be warm enough for resurfacing. Tidal heating—another potential source of heat caused by gravitational pull—cannot be occurring here, because nothing is pulling hard enough because of a lack of mass.

This presents a problem because the radioactive decay isn't enough to create the heat needed for a youthful surface (Freeman, Yuhas, Stromberg, Calderone, Thompson, Powell).

The Norgay and Hillary Montes.

The Norgay and Hillary Montes.

The Norgay Montes and the Hillary Montes

Also found on the surface of Pluto were these huge mountains named the Norgay Montes and the Hillary Montes. As tall as the American Rockies, the Montes are too big for them to be made of the ice seen in Tombaugh, for that material is weak on Pluto and cannot withstand the 0.06 g environment. The nitrogen, methane, and carbon monoxide ices seen on the surface just can't bear the structural load the mountains require.

So what can they be made of? Maybe if they were composed of water ice similar to the Tombaugh Regio, we would be in luck. If true, it would hint at a water ice mantle with a rocky core, based on those density readings. In fact, as much as a third of Pluto could be water ice based off the density readings seen (Stern "The Pluto" 27, Stern "Hot" 32-3, Stern "Puzzled" 26).

Dunes

Another mountain range seen on Pluto was the al-Idrisi Montes—which hinted at some layering on Pluto's surface—and nestled in it is Alcyonia Lacus, a potentially frozen liquid nitrogen lake. Dune-like activity was spotted near the al-Idrisi Montes and, based on some perpendicular patterns in the dunes, scientists suspect that they form with winds blowing in that direction rather than along the direction of the dunes.

Turns out, when at -230°C nitrogen and methane ice is at a great density to be a particulate and winds can blow snow down from the mountains near the dunes, and simulations show the average size of each grain to be 0.2 to 0.3 millimeters or roughly equivalent to their Earth brethren. Sublimation at the mountains gives the ice particles the kick they need to start moving and the winds take over from there, with gravity finally recapturing them once away from the mountains (Johnson, Parks).

Tying the System Together

In March of 2016, a connection was found between the mountains of Pluto and its atmosphere. Turns out the dwarf planet has another parallel to Earth: snow on mountains. Yes, mountains in the Cthulhu region seem to have brighter tops than the rest of the tholin-covered terrain. And when we compare these tips to methane ice distributions around the mountains, we have a match.

And where does that methane come from? The atmosphere, where the methane condensed and fell back to the surface. At the altitudes of the mountains, it remains in its frozen form (Berger "NASA May").

What else do the mountains of Pluto reveal about it? We will keep climbing that topic as we get more information.

Works Cited

  • Berger, Eric. "NASA may have found snow-covered mountains on Pluto." arstechnica.com. Conte Nast, 03 Mar. 2016. Web. 05 Aug. 2016.
  • Calderone, Julia. "The biggest discovery in new images of Pluto is what scientists didn't see." BusinessInsider.com. Business Insider Inc., 15 Jul. 2015. Web. 18 Aug. 2015.
  • Freeman, David and Eliza Sankar. "Dazzling New Pluto Photos Are The Best Ever Taken Of The Icy Dwarf Planet." HuffingtonPost.com. Huffington Post, 15 Jul. 2015. Web. 18 Aug. 2015.
  • Johnson, Scott K. "Frozen Pluto has wind-blown dunes made of methane sand." arstechnica.com. Conte Nast., 31 May 2018. Web. 13 Aug. 2018.
  • Parks, Jake. "How did Pluto form its mysterious dunes?" Astronomy.com. Kalmbach Publishing Co., 01 Jun. 2018. Web. 13 Aug. 2018.
  • Powell, Corey S. "The Passion of the Pluto-Philes." Discover Dec. 2015: 71. Print.
  • Stern, Alan. "Hot Results from a Cool Planet." Astronomy May 2016: 32-3. Print
  • ---. "Puzzled by Pluto." Astronomy Sept. 2017. Print. 26.
  • ---. "The Pluto System Explored." Astronomy Nov. 2015: 27. Print.
  • Stromberg, Joseph. "New Horizons' photos from the Pluto flyby are finally here — and they're amazing." Vox.com. Vox Media, 15 Jul. 2015. Web. 18 Aug. 2015.
  • Thompson, Amy. "First Pluto data reveals lots of terrain that is “not easy to explain” ars technica. Conte Nast., 17 Jul. 2015. Web. 19 Aug. 2015.
  • Yuhas, Alan. "Nasa unveils 'surprise' Pluto photos and New Horizons discoveries – as it happened." TheGuardian.com. Guardian News, 15 Jul. 2015. Web. 18 Aug. 2015.

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

© 2021 Leonard Kelley

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