Dr Vasili Dimitrov, whose work will be presented at the European Planetary Science Congress in Potsdam, said, “If Titan runs out of methane and loses its ‘veil’, it will become a completely different type of astrophysical body. Methane drives the chemical reactions in Titan’s atmosphere but, because it’s so highly reactive and therefore short-lived, it must be replenished. We need to find out just how much methane is stored in the primordial reserve in Titan’s interior at a level where it can escape to the surface. To do this, we need to know how efficiently the methane molecules were packed away when the reserve formed.“
The trapped methane can exist only in molecular structures called clathrates, which occur when “host” water molecules form a cage-like structure around a smaller “guest” molecule (in this case methane). The water crystallizes in a cubic system, rather than the hexagonal structure of normal ice, so that the cages are arranged in body-centred cubic packing. However, not all of the cages are occupied. The maximum efficiency in filling the cages is achieved only if conditions are optimal e.g. the structure forms slowly at temperatures close to absolute zero.
Dr Dimitrov said, “The conditions of Titan’s accretion and evolution are poorly understood, so we cannot yet say how many of the cages were filled and how much methane is contained in the reserve. In addition, we need to do some more experiments in the laboratory to find out more about the transfer of materials between layers.”
Beneath Titan’s surface, there is a permafrost crust that sits on a liquid or semi-liquid mixture of ammonia, methane and water. Beneath that, an icy layer surrounds a rocky core. It is unclear whether methane trapped in the icy layer next to the core has any means of escape. Dr Dimitrov said, “At the moment we can work out an upper and lower limit for the packing efficiency, but this doesn’t tell us which side of the critical value Titan’s methane stockpile falls. With more experiments, together with the data supplied by the Cassini-Huygens mission, we should be able to answer the question of whether this fascinating world will keep its veil of mystery.”
Being able to estimate the packing efficiency of methane in clathrates could also have important applications back on Earth. According to some estimates, the overall methane stock in the Earth’s natural clathrates may be four times higher than the oil stock. Thus, methane extracted from clathrates could one day become a major fuel source for the mankind.
Anita Heward | alfa
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Satellites in near-Earth orbit are at risk due to the steady increase in space debris. But their mission in the areas of telecommunications, navigation or weather forecasts is essential for society. Fraunhofer FHR therefore develops radar-based systems which allow the detection, tracking and cataloging of even the smallest particles of debris. Satellite operators who have access to our data are in a better position to plan evasive maneuvers and prevent destructive collisions. From April, 25-29 2018, Fraunhofer FHR and its partners will exhibit the complementary radar systems TIRA and GESTRA as well as the latest radar techniques for space observation across three stands at the ILA Berlin.
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In just a few weeks from now, the Chinese space station Tiangong-1 will re-enter the Earth's atmosphere where it will to a large extent burn up. It is possible that some debris will reach the Earth's surface. Tiangong-1 is orbiting the Earth uncontrolled at a speed of approx. 29,000 km/h.Currently the prognosis relating to the time of impact currently lies within a window of several days. The scientists at Fraunhofer FHR have already been monitoring Tiangong-1 for a number of weeks with their TIRA system, one of the most powerful space observation radars in the world, with a view to supporting the German Space Situational Awareness Center and the ESA with their re-entry forecasts.
Following the loss of radio contact with Tiangong-1 in 2016 and due to the low orbital height, it is now inevitable that the Chinese space station will...
Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, provider of research and development services for OLED lighting solutions, announces the founding of the “OLED Licht Forum” and presents latest OLED design and lighting solutions during light+building, from March 18th – 23rd, 2018 in Frankfurt a.M./Germany, at booth no. F91 in Hall 4.0.
They are united in their passion for OLED (organic light emitting diodes) lighting with all of its unique facets and application possibilities. Thus experts in...
A new scenario seeking to explain how Mars' putative oceans came and went over the last 4 billion years implies that the oceans formed several hundred million...
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