Researchers Find Methane Ice Dunes on Pluto | Planetary Science


Researchers Find Methane Ice Dunes on Pluto | Planetary Science

Finger-print like pattern observed near al-Idrisi Montes mountain on Pluto. Specifically, Pluto's atmosphere captures small particles of methane (instead of sand) from the base of a nearby mountain range before relatively strong winds carry the particles away.

Looking at Pluto's surface for the first time, Radebaugh said she and her team are already learning about Earth and how the solar system was formed.

"We have been focusing on what's close to us, but there's a wealth of information in the distant reaches of the solar system too", said Dr. Jani Radebaugh, Associate Professor in the Department of Geological Sciences at Brigham Young University.

On Earth, we have a rich variety of dunes dependent on the composition and size of the grains and the strength and direction of the wind.

A scientific team headed by British researchers published the findings yesterday in the journal Science.

The ridges appeared in images taken by the New Horizons spacecraft in 2015, but scientists were baffled as to how dunes could form in Pluto's thin atmosphere. The mounds stretch for more than 12 miles and occupy an area equivalent to twice that of Utah Lake. In the western lobe of that heart, a plain called Sputnik Planitia, Telfer and other planetary scientists spotted something peculiar. The atmosphere, composed mainly of nitrogen with hints of methane and carbon monoxide, is 100,000 times thinner than Earth's.

But perhaps the most surprising outcome of New Horizons' journey was not the deeper peek into Pluto's oddities. They believe that sublimation, which converts solid nitrogen directly into a gas, results in sand-sized grains of methane being released into the environment. "But we cannot exclude that it is nitrogen ice".

Once airborne, the particles are pushed by winds that blow between 18 and 24 miles an hour. Scientists came to the conclusion that the slopes of the mountains on Pluto snow consisting of methane and possibly nitrogen, which under certain conditions is transferred by the winds in the valley. The upward force is what drives the piles of particles at the surface. It would just kind of feel a lot like you're on another sand dune on the Earth'.

Comparing to Earth, Pluto has lower surface pressure up to 100k times and scientists consider it to be the main factor for the gathering of solid methane. The temperature gradients in the granular ice layer, caused by solar radiation, also play an important role in the onset of the saltation process [movement of particles over an uneven surface]. "The New Horizons data has given us a new level of detail, but we had to work hard to explain how it was possible to get the supply of sediment, a non-cohesive surface and wind you need for dunes", Matt Telfer, from the University of Plymouth in the United Kingdom and lead author of the paper describing the formations, said in a statement Thursday.

The researchers also think that the dunes are young, rather than ancient, and might still be active.

Pluto might not be an official planet anymore but that doesn't mean the frozen world is any less interesting from a scientific perspective.