Titan News 2020
February 19, 2020 : New Quantum Mechanical Calculations Upon Azotosomes Imply That Their Development Is Unlikely In The Hypothetical Biosphere Of Titan
A new study entitled « Can polarity-inverted membranes self-assemble on Titan ? », published in Science Advances on January 24, 2020 and proposed by H. Sandström and M. Rahm, reveals quantum mechanical calculations upon azotosomes which imply that those molecules which represent nitrogen-containing compounds may not develop in the hypothetical biosphere of Titan. In a relatively recent past, some researchers had advanced the possibility of a Titanian biosphere involving azotosomes. Azotosomes appeared to be good candidates for the potential development of cell membranes of any exotic lifeform on Saturn's largest moon. The new research work tends to show that azotosomes are unlikely for any autonomous organism on the Hazy Moon. The scientists advance that in an environment where temperatures are extremely low and where liquid water is absent, cell membranes can be ruled out for any lifeform. In terms of thermodynamics, the formation and the development of azotosomes on the Opaque Moon appear unlikely. Those theoretical membranes may not be in a position to self-assemble in the extreme environment of the giant moon.
On the basis of what we observe in our own biosphere, we have had the opportunity to determine that the membranes of the cells play a key role for the development of typical organisms. The membranes of the cells are composed of lipid bilayers which are hydrophobic or amphiphilic. Life on Earth is based on liquid water and all creatures are composed of cells in which various chemical reactions can take shape without the potential disruptions in the potential interactions between liquid water and other compounds located outside the cell and the « factory » of the cell. Numerous researchers believe that the lipid bilayer membrane is a key aspect of life in an environment dominated by liquid water or in an environment where water can be found in its liquid form. In the Solar System, the Earth is the only planetary body where water can be encountered in its liquid form on the surface. On Mars, there are not the right combinations of atmospheric pressure and environmental temperature for the stable presence of liquid water on the surface for instance. On Venus, the greenhouse effect is so high that the environmental temperature at the level of the surface is too high for the presence of liquid water on the surface.
The image in the upper part of this table reveals a raw view of Saturn's largest moon Titan obtained on September 12, 2017 from the Cassini spacecraft. The image whose file name is N00289163.jpg was acquired using the CL1 filter and the CB3 filter. The image had not been validated or calibrated at the time of the observation and was going to be archived with the Planetary Data System proposed by NASA. The image in the lower part of this table represents a colorized view of the raw image. One can clearly notice a portion of Kraken Mare. Credit for the raw image: NASA/JPL-Caltech/Space Science Institute. Credit for the colorization of the original image: Marc Lafferre, 2020.
January 27, 2020 : Some Researchers Have Suggested At The 235th Meeting Of The American Astronomical Society That The Haze Of Pluto May Resemble The Haze Of Titan
A group of researchers has revealed, during a presentation on January 8, 2020 at the 235th meeting of the American Astronomical Society taking place in Honolulu in the state of Hawaii, that the haze identified in the atmosphere of the Dwarf Planet Pluto may look like the haze of Saturn's largest moon Titan. Researchers had collected a huge amount of data regarding Titan's atmosphere during the Cassini-Huygens mission in the Saturn System from 2004 to 2017. On July 14, 2015, the New Horizons spacecraft performed the first flyby of Pluto and Charon revealing a remarkably complex world with a varied landscape and with a thin atmosphere composed of several layers. In fact, researchers were in a position to determine that Pluto's atmosphere is a blue atmosphere like the atmosphere of our planet and that a haze evolves in that exotic gas blanket. The team involving Bonnie Buratti who is a planetary scientist at NASA's Jet Propulsion Laboratory in California advanced that the haze of Pluto is rich in organics like the haze of Titan. The atmosphere of Pluto is particularly thin like the atmosphere of Neptune's largest moon Triton but the haze of Pluto may be closer to the haze of Titan in terms of composition.
Pluto and Triton represent small worlds whose size is roughly similar. Those planetary bodies appear to be remarkably active in terms of geology. In spite of their relatively low gravity, they contain a thin atmosphere dominated by nitrogen. Most moons or icy bodies in the Solar System are devoid of any atmosphere but Titan, Triton and Pluto unveil an atmosphere. There is apparently the right combination of environmental temperature and gravity on each planetary body to allow the presence of an atmosphere. The atmosphere of Titan is reminiscent of the atmosphere of the Early Earth and of the Earth today because that gas layer is mostly composed of molecular nitrogen. Unlike the atmosphere of Pluto and Triton, the atmosphere of the Orange Moon appears completely opaque from outer space in the visible spectrum. The global haze of Saturn's largest moon prevents us from discerning surface features from outer space. The atmosphere of Pluto appears more optically thick than the atmosphere of the strange moon of Neptune Triton. The difference may be related to a carbon-rich haze in the environment of Pluto. The reddish areas observed on Pluto imply the potential presence of tholins, a type of mud or sludge rich in organics and hydrocarbons.
The image above reveals a portion of Titan in the lower part of the view as well as a portion of Pluto in the upper part of the view. The original view of Titan was obtained on January 30, 2012 from the Cassini spacecraft. The original view of Pluto was obtained on July 14, 2015 from the New Horizons spacecraft. The views of Titan and Pluto are at scale. Each side of the image represents about 1000 km. One can notice, in particular, a multitude of layers in Pluto's atmosphere and a detached haze layer in Titan's atmosphere. A parallel can be drawn between the haze on Titan and the haze on Pluto. Credit for the original view of Titan: NASA/JPL-Caltech/Space Science Institute. Credit for the original view of Pluto: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute. Credit for the montage: Marc Lafferre, 2020.
January 17, 2020 : Some Researchers May Have Solved The Mystery Of The Reversed Spin Of The Huygens Probe During Its Atmospheric Descent
About 15 years ago, on January 14, 2005, the Huygens probe released from the Cassini orbiter performed an atmospheric descent and landed on the surface of Saturn's largest moon Titan for the first time in history. The Huygens probe which was proposed by ESA and ASI had separated from the Cassini spacecraft proposed by NASA at the end of December 2004. During the atmospheric plunge of January 14, 2005, the Huygens probe started to spin the wrong way and engineers and researchers had not anticipated that configuration. That mystery may have been solved thanks to recent tests or simulations. In fact, during the atmospheric journey, some instruments of the probe may have generated an unexpected torque opposite to that engendered by the 36 angled vanes of the Huygens probe. The vanes played a key role since they were used to control the rotation of the probe during its descent inside the deep and thick atmosphere of the giant moon. The atmosphere of Titan like the atmosphere of Venus or like the atmosphere of Mars makes any parachute useful for any probe that dives to the surface.
Researchers have been in a position to determine that two devices of the Huygens probe, the Separation Subsystem (SEPS) and the Radar Altimeter (RA) antennae, actually engendered an unexpected torque opposite to that generated by the multiple vanes. That phenomenon was strengthened due to the alteration of the gas flow around the atmospheric probe by the vanes which led to a rise in the amplitude of the « negative torque ». Let's point out that the negative torque corresponds to the effect that made the Huygens module flip its direction of rotation. The unexpected effect turned out to exceed the influence of the vanes. It is crucial for engineers to clearly understand the mechanisms that led to the unexpected configuration in the prospect of the development of future probes sent to extraterrestrial atmospheres like the atmosphere of Venus, Mars, Titan or the four Gas Giants. The behavior of any atmospheric probe can engender scientific failures. That's why engineers and scientists must be in a position to anticipate any scenario during the complex phase of the atmospheric descent.
The image above represents a mosaic of aerial views of Titan's landscape obtained from the DISR of the Huygens probe during its atmospheric plunge on January 14, 2005. The views were acquired at an altitude of approximately 8 km and the resolution of the landscape features is about 20 meters per pixel. One can clearly notice a sharp contrast between bright hills composed of a network of dark channels and a dark plain which seems quite uniform. The Cassini-Huygens mission represented the outcome of a collaboration between ESA, NASA and ASI. Image credit: ESA/NASA/JPL/University of Arizona.
January 7, 2020 : A New Research Work Involving Takahiro Iino Reveals That ALMA Has Measured The 14N/15N Isotopic Ratio In CH3CN Of The Opaque Atmosphere Of Titan
A new research work proposed on January 7, 2020 by a team of researchers composed of Takahiro Iino, Hideo Sagawa and Takashi Tsukagoshi and presented in Arxiv reveals the measurement of the 14N/15N isotopic ratio in CH3CN in the atmosphere of Saturn's largest moon Titan via ALMA. The planetologists were in a position to detect submillimeter rotational transitions of CH3C15N found at the 338 GHz band in the spectra of Titan's opaque atmosphere thanks to the analysis of archival data collected by the Atacama Large Millimeter/submillimeter Array (ALMA). A comparison between those observations and the simultaneously observed CH3CN lines at the 349 GHz band, which allow us to study the area from the altitude of 160 km to the altitude of about 400 km, allowed the researchers to deduce the value of the ratio 14N/15N in CH3CN at about 125. The level of accuracy remains limited but it allows the scientists to advance that the value of 14N/15N for CH3CN is higher than the values that have been previously determined and theoretically predicted for HCN and HC3N. The difference may be related to the different N2 dissociation factors whose impact depends on the altitude as proposed by a recent photochemical model.
The isotopic ratio between 14N and 15N can vary in the various nitriles present in Titan's atmosphere. The differences are closely related to the production processes of the molecules. The dissociation processes of N2 can be generated via the action of ultraviolet light from the Sun, via the action of magnetospheric electrons or via the action of galactic cosmic rays. Regarding the nitrile CH3CN, a photochemical model predicted a value of 120-130 in the lower part of the stratosphere for the isotopic ratio 14N/15N. The expected value is much higher than that for the nitriles HCN and HC3N which is, approximately, between 67 and 94. The value of 125 for the ratio 14N/15N in the molecule CH3CN which was measured by ALMA appears clearly higher than the value measured and predicted for the ratio 14N/15N in the molecules HCN and HC3N. The dissociation factors which depend on the altitude must be considered. Researchers are particularly interested in the chemistry of Titan's complex atmosphere which represents, to a certain extent, a soup of various molecules, elements or ions and which may resemble the atmosphere of the Early Earth.
The image in the upper part of the table reveals a raw image of Titan's disk obtained from the Cassini spacecraft on December 14, 2009. The image whose file name is N00148433.jpg was acquired using the CL1 filter and the MT3 filter. The view had not been validated or calibrated. A validated or calibrated view was going to be archived with the Planetary Data System proposed by NASA. The image in the lower part of the table represents a colorized version of the raw image. Credit for the raw image: NASA/JPL-Caltech/Space Science Institute. Credit for the colorization of the raw image: Marc Lafferre, 2020.
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