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Learning the secrets of a mysterious misty moon

With its tantalizingly secret surface covered in dense golden-orange fog, Saturn’s largest moon Titan was long considered a mysterious and icy lunar world. However the Cassini-Huygens The mission changed all that when the Huygens lander it floated to the surface of the hazy moon in 2004, and looked at Titan’s well-hidden face behind its strange orange mask. Although the Cassini-Huygens The mission ended in 2017, planetary scientists are still investigating the treasure trove of information it sent to Earth before it was intentionally destroyed by mission scientists. In October 2019, a team of scientists led by a University of Hawaii chemistry professor and researcher (Manoa) announced that they had been able to provide answers to important questions about Titan’s strange surface. Researchers say they have unraveled the origin and chemical makeup of Titan’s alien dunes.

Physical chemist Dr. Ralf I. Kaiser and his colleagues examined remote sensing data provided by Cassini-Huygens regarding Titan. Titan is the only body in the Solar System, other than Earth, that has a solid surface, lakes, and a substantial atmosphere with a pressure of about 1.5 atmospheres at surface level. Images and data provided by Cassini-Huygens revealed the existence of vast longitudinal dunes in this hazy orange lunar world. The dunes are located in the equatorial deserts of Titan and reach heights of up to 100 meters, making them similar in size to the Egyptian pyramids of Giza. However, while Earth’s dunes are composed primarily of silicates, imaging studies revealed that Titan’s dunes are composed of a different material. Titan’s dunes were shown to contain dark organic compounds that, until this new study, were of indeterminate origin and chemical composition.

The team from the University of Hawaii at Manoa (UH), which also included Dr. Matthew Abplanalp, then a graduate student at UH, discovered the existence of acetylene ice in the dunes of Titan. Acetylene is a chemical that is used on Earth in welding torches. It exists in the equatorial regions of Titan, but at low temperatures to the representatives of high-energy galactic cosmic rays. Scientists found a fast cosmic ray-driven chemistry that causes simple molecules like acetylene to undergo a radical change into more complex organic molecules like benzene and naphthalene. Naphthalene is a compound found in Earth’s well-known mothballs and exists on the exotic surface of Titan. These processes also occur in the space between stars. (interstellar medium) in hydrocarbon-rich layers of interstellar nanoparticles.

This new research has been published in the journal Progress of science under the title Low-temperature synthesis of polycyclic aromatic hydrocarbons in Titan’s surface ices and in airless bodies.

Polycyclic aromatic hydrocarbons (PAH) They are organic compounds that contain only carbon and hydrogen, and are composed of multiple aromatic rings.

The strange face behind the smoky orange mask of a distant moon

Titan is the largest moon of the ringed gas giant planet, Saturn, as well as the second largest moon in our Solar System. Only Ganymede of Jupiter is bigger than Titan. Here, in the icy realm of the quartet of majestic, giant and gaseous outer planets – Jupiter, Saturn, Uranus and Neptune – our Sun shines with a weaker fire than in the inner Solar System where Earth is located – along with the other three solid and relatively small planets: Mercury, Venus, and Mars.

Titan is a world racked by hydrocarbons, which bears an uncanny resemblance to the way our own planet was, long ago, before life emerged and evolved here. (prebiotic). Like Earth, Titan experiences frequent downpours, swirling seas, and eroding organic material. However, on Titan, it’s not liquid water that fills its alien seas, rivers, and lakes with lovely little raindrops. In this strange, mist-filled lunar world, life-sustaining liquid water is replaced by strange, lazy, large droplets of methane. The surface of Titan receives a “rain of terror”; On Titan, it rains gasoline. On this strange moon, atmospheric molecules made up of methane are perpetually ripped apart by sunlight, and the resulting atmospheric smog floats to the surface, where it accumulates as organic settlements that rapidly steal methane from the atmosphere. Titan’s surface is well coated with material from ancient atmospheres that are long gone.

There is no obvious source of Titan’s methane, with the exception of the evaporation of methane that originates from hydrocarbon-filled polar lakes. The problem is that Titan’s strange lakes contain only about a third of the methane in Titan’s atmosphere. This methane will soon be depleted on geologic time scales.

Titan itself is Saturn’s sixth gravitationally rounded moon, and this large lunar world is often described as “planet-like.” Titan is twice the size of Earth’s comparatively large Moon, as well as being 80% more massive. In fact, Titan is larger than the planet Mercury, our star’s innermost major planet. However, Titan is only 40% more massive than Mercury.

Titan was discovered by the Dutch astronomer Christiaan Huygens on March 25, 1655 and was the first moon of Saturn to be observed. It is the sixth known natural planetary satellite, after Earth’s Moon and the quartet of Galilean moons of Jupiter (Io, Europa, Ganymede, and Callisto). The oven Galilean moons they were discovered by the great Italian astronomer Galileo Galilei in 1610. Titan surrounds its ringed parent planet 20 radii from Saturn. From Titan’s strange hydrocarbon-cut surface, Saturn would subtend an arc of 5.09 degrees, and would appear 11.4 times larger in its dense golden-orange sky than the Moon from Earth.

Titan is composed primarily of ice and rocky material, which is believed to differ into a rocky core surrounded by various layers of ice, including a crust composed of ice Ihand a subsurface layer of liquid water rich in ammonia. Before the age of space exploration, Titan’s heavy and opaque atmosphere made it impossible for planetary scientists to study its mysterious surface, until Cassin-Huygens mission. This joint mission by NASA, the European Space Agency, and the Italian Space Agency to the Saturn system, finally revealed the strange face of the moon that had been well hidden behind its smoky orange mask since its discovery in 1655. Cassini-Huygens provided valuable new information, including the discovery of the liquid hydrocarbon lakes that accumulate in Titan’s polar regions. The geologically young surface is mostly smooth, with relatively few impact craters. Smooth surfaces are young, while heavily cratered surfaces are older. This is because young surfaces have been resurfaced, such as that of Titan. However, the mountains, as well as various potential criolcanes (ice volcanoes), have been observed in this strange and distant lunar world.

Titan’s atmosphere is made up mostly of nitrogen; The smallest components result in the formation of thick hydrocarbon clouds composed of methane and ethane, all of which are cooked in a witch’s cauldron of dense organic smog that blankets this tortured lunar world. Titan’s climate, including wind and rain, sculpts surface features that appear eerily similar to our own planet, such as its dunes, lakes, rivers, and seas (probably brimming with liquid methane and ethane). Titan also has deltas and is subject to seasonal weather patterns that are similar to Earth’s. With its liquids, both surface and subsurface, and abundant nitrogen atmosphere, Titan’s exotic methane cycle is analogous to Earth’s water cycle, but at much cooler temperatures of about -290.5 degrees F.

Mysterious dunes of a misty and wet moon

“The dunes of Titan represent the dominant surface carbon sink in Titan’s organic chemistry. Therefore, unraveling the origin and chemical pathways to form the organic material of the dunes is vital not only to understanding the chemical evolution of Titan, but also to understand how similar the chemistries are to Titan and on Earth it could have been before life emerged on Earth 3.5 billion years ago, “noted Dr. Abplanalp on October 17, 2019. University of Hawaii press release. Dr. Abplanalp is now a researcher at the Weapons Division of the Naval Air Warfare Center in China Lake.

“These processes eventually provide the molecular building blocks not only for the organic dunes of Titan, but also for the organic ones in airless bodies in general, as in Kuiper belt objects as a dwarf planet Makemake. Low temperature synthesis of PAH of acetylene ices represents a fundamental shift from currently accepted perceptions that PAH The formation takes place only in the gas phase at elevated temperatures of about 1,000 K, as in combustion processes ”, he added.

Tea kuiper belt it is a remote region of our Solar System located beyond the orbit of the outermost planet Neptune. It is believed to contain, not only Tiny planets, but also a myriad of frozen comet nuclei, asteroids, and a variety of other small bodies made primarily of ice that exist in the deep freeze of our Solar System.

These new findings have unprecedented implications for future space missions to Titan. NASA is currently planning to land a flying robot, named Dragon-fly, on the surface of Titan, the favorite target in the search for life on worlds beyond Earth, as well as the molecular precursors of life. Dragon-fly– which is about the same size as a car – is a quadcopter that is equipped with instruments that can identify large organic molecules. It is scheduled to launch aboard a rocket in 2026, reach its goal in 2034, and then fly to numerous locations hundreds of miles away. Dragon-fly it will land near Titan’s equator near the organic dunes, thus providing an in situ glimpse into potentially biorelevant organics that exist in a deep frozen state. In this way, the quadcopter will move quickly to observe the unknown.

“Overall, this study advances our understanding of complex organic compounds and the fundamental chemical processing of simple molecules in deep space and provides a scientifically robust and proven mechanism for the formation of aromatic structures in extreme environments in low-temperature ices. Titan is rich in nitrogen, incorporating nitrogen into these PAH it can also lead to carbon-nitrogen traces (parts of a molecule) that are prevalent in contemporary biochemistry, such as DNA and RNA-based nitrogen bases, “explained Dr. Ralf Kaiser on October 17, 2019. University of Hawaii press release.