Tuesday, March 15, 2016

Instagram favs - This is what geologists call ‘bladed’ terrain in a region known as Tartarus Dorsa, located in the rough highlands on the eastern side of Tombaugh Region on Pluto. A moment’s study reveals surface features that appear to be texturally ‘snakeskin’-like, owing to their north-south oriented scaly raised relief. A digital elevation model created by the New Horizons’ geology shows that these bladed structures have typical relief of about 550 yards (500 meters). Their relative spacing of about 3-5 kilometers makes them some of the steepest features seen on Pluto. Spectroscopic measurements of this region made by New Horizons’ Linear Etalon Imaging Spectral Array (LEISA) instrument show that this region of Pluto’s surface has a predominance of methane (CH4)—with a smattering of water as well. Naturally, one then would ask, “Can pure methane ice support such steep structures under Pluto’s gravity and surface temperature conditions over geologic time?” The answer is a meek “maybe.” To date, there are only two known published studies examining the rheological properties (i.e., how much a material deforms when stresses are applied to it) of methane ice in the extreme temperature range of Pluto—a bitterly cold -300 to -400 degrees Fahrenheit. According to one study, the answer is a definite ‘no,’ because methane ice of those dimensions would flatten out in a matter of decades. Yet in another study, methane ice may maintain such a steepened structure if the individual CH4 ice grains constituting the collective ice are large enough. Which study is right? Or is there a way to reconcile them? This is something we simply do not know at the moment. #NASA #newhorizons


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