Highland is covered by hundreds of meters high peaks of methane ice

Dangerous terrain: The equatorial upland of Pluto is covered with gigantic ice peaks that protrude knife like blades. Each of these blade tips can be hundreds of meters high - as high as a skyscraper. Why these mysterious ice-blades exist and how they are created NASA researchers have unmasked now. Accordingly, the peaks consist of methane ice and have been formed by partial sublimation of the ice.

On Plutos Highland Tartarus Dorsa, ice peaks rise hundreds of meters. They are a gigantic version of the peninsula known as the Andes (right) © NASA, ESO

The dwarf planet Pluto always provides surprises. The supposedly dead, distant ice world is increasingly proving to be a rather dynamic heavenly body. There are flowing glaciers, convection currents from ice, fog clouds and perhaps even active ice volcanoes. In addition, the entire dwarf planet could once have been tilted by 60 degrees.

Hundreds of meters high blades of ice

Now, NASA researchers have investigated another exotic landscape of Pluto: the ribs of the equatorial highlands Tartarus Dorsa. On it, the images of the NASA probe New Horizons show a pockmarked terrain, which on closer investigation proved to be a formation of densely close ice peaks.

These ice peaks protrude hundreds of meters above the ground, resembling upright giant knives.

This blade terrain only occurs in extreme altitudes of more than two kilometers above the average radius, and within about 30 degrees of the equator, said Jeffrey Moore of NASA's Ames Research Center and his colleagues.

Sublimation formed methane ice formations

But how have these strange giant ice blades come into being? The researchers assume that the ice peaks have a similar origin to the so-called Penitentes or "penitent ice" on the earth. These ice columns are formed because snow and ice crystals do not melt but sublime in the dry and cold uplands. Because this does not happen uniformly, tips of harder ice remain.

Similar could happen on Pluto - with the difference that methane ice instead of water ice forms the peaks.

Apparently Pluto is also experiencing climate changes, explains Moore.

In cold periods, methane crystallizes on the crests - similar to hoarfrost on the earth.

When the dwarf planet gets warmer, the methane ice begins to evaporate, the researcher said.

Pluto and its Ice Blade Terrain © NASA / Ames

Also elsewhere on Pluto

The huge methane ice blades on Pluto are thus an indication that the climate of the icy dwarf planet must be variable. The researchers suspect that its climate changes have fluctuated over the time of millions of years. At the same time, the new findings suggest that there might be similar ice blades on other equatorial heights of Pluto.

Source: Icarus, 2017; doi: 10.1016 / j.icarus.2017.08.031