Pluto’s largest moon, Charon, captured by NASA’s New Horizons spacecraft on July 14, 2015 (Reuters)
When NASA’s small New Horizons spacecraft traveled three billion miles to Pluto, it detected something very mysterious on Pluto’s moon Charon: a red “cap.”
The data from the probe, powered by a Star Trek-style ionic unit, have been combined this week with data from lab experiments, and scientists now believe they can understand what constitutes the strange red dot.
The red zone appears to be a sticky organic residue created as methane decomposes by solar wind into more complex molecules.
Randy Gladstone of the Southwest Research Institute said, “Before New Horizons, Hubble’s best images of Pluto revealed only a faint blur of reflected light.”
“In addition to all the fascinating features discovered on Pluto’s surface, the overflight revealed an unusual feature to Charon, a striking red cap centered at its north pole.”
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Shortly after the 2015 meeting, New Horizons scientists proposed that a “toline-like” reddish material at Charon’s pole could be synthesized by ultraviolet light that shattered methane molecules.
These are captured after escaping from Pluto and then frozen in the polar regions of the Moon during their long winter nights.
Tolins are sticky organic wastes formed by light-driven chemical reactions, in this case the ultraviolet glow Lyman-alpha dispersed by interplanetary hydrogen atoms.
Dr. Ujjwal Raut of the Southwest Research Institute, “Our findings indicate that drastic seasonal increases in Charon’s fine atmosphere, as well as light breaking the condensed methane frost, are key to understanding the origins of the red polar zone of Charon.
“This is one of the most illustrative and clear examples of surface-atmospheric interactions observed to date in a planetary body.”
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The team realistically replicated Charon’s surface conditions at SwRI’s new Center for Astrophysics and Space Science Experiments (CLASS) to measure the composition and color of hydrocarbons produced in the winter hemisphere. Charon when methane freezes under the Lyman-alpha glow.
The story goes on
The team introduced the measurements into a new atmospheric Charon model to show that methane decomposes into waste at the north polar point of Charon.
Raut said: “Our team’s new ‘dynamic photolysis’ experiments provided new limits to the contribution of interplanetary Lyman-alpha to the synthesis of Charon’s red matter.
Our experiment condensed methane in an ultra-high vacuum chamber under exposure to Lyman-alpha photons to faithfully replicate conditions to Charon’s poles. “
SwRI scientists also developed a new computer simulation to model Charon’s thin methane atmosphere.
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The team introduced the results of SwRI’s ultra-realistic experiments into the atmospheric model to estimate the distribution of complex hydrocarbons arising from the decomposition of methane under the influence of ultraviolet light.
The model has polar zones generating mainly ethane, a colorless material that does not contribute to a reddish color.
Raut said: “We believe that ionizing radiation from the solar wind breaks down polar ice cooked with Lyman-alpha to synthesize increasingly complex, red materials responsible for the unique albedo of this enigmatic moon.
“Ethane is less volatile than methane and stays frozen on the surface of Charon long after the spring sun rises. Exposure to solar wind can turn ethane into persistent reddish surface deposits that contribute to the layer. Charon’s Red. “
Look, NASA has created overflight videos of Pluto and Charon