February 15, 2024: Carbon Migration Into The Presumed Subsurface Ocean Of Titan Via Impact Cratering May Be Too Limited For The Development Of Life
A new study entitled "Organic Input to Titan's Subsurface Ocean Through Impact Cratering", proposed by a team led by Catherine Neish and published in the journal Astrobiology on February 2, 2024 suggests that the amount of organics and glycine in particular migrating from the surface to the hypothetical subsurface ocean of Titan under the action of impact cratering appears too limited for the emergence and the development of life. The planetologists assumed that impact craters engender melt deposits containing liquid water. The mean density of the material is higher than the mean density of the icy crust so that the material rich in organics and rich in glycine in particular will tend to migrate toward the presumed subsurface ocean rich in liquid water. The team was in a position to evaluate the amount of organic molecules that could be injected into the subsurface liquid layer. The specialists mobilized known yields for HCN (Hydrogen cyanide) and the haze hydrolysis of the giant moon to determine the amount of glycine generated in the melt lenses and obtained a range of potential flux rates of glycine from the ground to the presumed subsurface ocean.
The range of possible flux rates of glycine appears to be between 0 and 10^11 mol/Gyr for HCN hydrolysis and appears to be between 0 and 10^14 mol/Gyr for haze hydrolysis. These fluxes imply an upper limit for biomass productivity of about 10^3 kg C/year on the basis of a glycine fermentation metabolism. This upper limit appears clearly low for the potential emergence or development of life. This upper limit for biomass productivity is even significantly lower than recent evaluations of the hypothetical biomass production taking shape in the presumed subsurface ocean of the tiny moon Enceladus. Yet, Titan is regarded as a world rich in organics and hydrocarbons but the concentration of molecules rich in carbon elements inside the hypothetical subsurface ocean of the Opaque Moon may be too limited for the emergence or the development of any lifeform based on liquid water and carbon. However, the planetologists of the research work focused their attention on the influence of impact cratering upon the amount of organics transferred from the surface to the presumed subsurface ocean. They don't consider other potential sources of organics or hydrocarbons that can fuel that hypothetical ocean.
The image above reveals a portion of a radar swath obtained with the Radar Mapper of the Cassini orbiter during the T17 flyby performed on September 7, 2006. Each side of the view represents approximately 100 kilometers. One can notice a circular feature that may represent an impact crater. That crater is known as the Ksa crater. Impact craters on Titan are likely to engender transfers of hydrocarbons or organics from the surface to the hypothetical subsurface ocean rich in liquid water. Credit for the original view: PDS Image Atlas. Montage credit: Marc Lafferre, 2024.
January 9, 2024: The Famous "Magic Islands" Of Titan May Represent Relatively Porous Organic Glaciers According To A New Study
A new research work entitled "The Fate of Simple Organics on Titan's Surface: A Theoretical Perspective", published in Geophysical Research Letters on January 4, 2024 and proposed by a team of researchers involving Xinting Yu, Yue Yu, Julia Garver, Xi Zhang and Patricia McGuiggan suggests that the famous "Magic Islands" of Titan may represent relatively porous organic glaciers. The Magic Islands had been identified in 2014 thanks to radar data taken from the Cassini spacecraft during its orbital dance in the system of Saturn and its numerous moons. In the land of lakes and seas found in the high latitudes of the northern hemisphere of Saturn's largest moon, transient islands seem to be present from time to time. During the long mission of the Cassini orbiter in the Saturn System, from 2004 to 2017, we had obtained a multitude of radar images and we have been in a position to perform an analytical work regarding the evolution of the lakes, seas or rivers found in the high latitudes of the Opaque Moon. In Ligeia Mare or Kraken Mare, new bright patches had appeared inside the pools and they had progressively vanished in just a few weeks.
What do those enigmatic bright patches represent ? Are they really islands ? Do they represent an area of strong waves ? Do they represent a field of bubbles related to cryovolcanic features ? Are they transient icebergs ? Are they related to a biological system within the pool ? The debate is far from being over and several hypotheses can be put forward. In the new study proposed by UTSA professor Xinting Yu and her collaborators, the hypothesis that the Magic Islands could in fact represent relatively porous organic glaciers is rigorously considered. The floating chunks of porous, icy organic solids may be closely related to atmospheric phenomena. There is a complex chemistry in the atmosphere of that giant moon. The haze of the atmosphere is closely related to the light from the Sun. Ultraviolet radiations engender various chemical reactions in the upper atmosphere. The atmosphere of Titan is in fact a soup of elements, molecules or radicals where relatively complex molecules can emerge and fall toward the surface. The atmosphere of that orange world is clearly remarkable because it may look like the atmosphere of the Early Earth. Like the atmosphere of the Blue Planet, the atmosphere of Titan is dominated by molecular nitrogen.
The image above reveals a portion of a radar swath obtained from the Cassini orbiter during the T-104 flyby performed on August 21, 2014. Each side of that portion is approximately 100 kilometers long. The file name of the original view is BIFQI77N241_D261_T104S05_V03.jpg. One can notice a relatively dark and uniform area representing a portion of a pool of hydrocarbons as well as a bright and irregular area representing a portion of the coastline. Several small bright patches can be identified inside the pool. They may correspond to islands, icebergs or glaciers. Are those features stable over time ? Credit for the original image: PDS Image Atlas. Montage credit: Marc Lafferre, 2024.