Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Does Titan’s methane originate from underground?

03.03.2006


Data from ESA’s Huygens probe have been used to validate a new model of the evolution of Titan, Saturn’s largest moon, showing that its methane supply may be locked away in a kind of methane-rich ice.



The presence of methane in Titan’s atmosphere is one of the major enigmas that the NASA/ESA/ASI Cassini-Huygens mission is trying to solve.

Titan was revealed last year to have spectacular landscapes apparently carved by liquids. The Cassini-Huygens mission also showed that there is not after all a lot of liquid methane remaining on the moon’s surface, and so it is not clear where the atmospheric methane gas comes from.


Using the Cassini-Huygens findings, a model of Titan’s evolution, focusing on the source of Titan’s atmospheric methane, has been developed in a joint study by the University of Nantes, France, and the University of Arizona in Tucson, USA.

"This model is in agreement with the observations made so far by both the Huygens probe that landed on Titan on 14 January 2005 and the remote sensing instruments on board the Cassini spacecraft," said Gabriel Tobie, of the Laboratoire de Planetologie et Geodynamique de Nantes, and lead author of an article in Nature.

There is a difference between volcanism on Earth and ‘cryovolcanism’ on Titan. Volcanoes on Titan would involve ice melting and ice degassing, which is analogous to silicate volcanism on Earth, but with different materials.

Methane, playing a role on Titan similar to water on Earth, would have been released during three episodes: a first one following the accretion and differentiation period, a second episode about 2000 million years ago when convection started in the silicate core and a geologically recent one (last 500 million years ago) due to enhanced cooling of the moon by solid-state convection in the outer crust.

This means that Titan’s methane supply may be stored in a kind of methane-rich ice. The scientists suggest that the ice, called a ‘clathrate hydrate’, forms a crust above an ocean of liquid water mixed with ammonia.

"As methane is broken down by light-induced chemical reactions over a timescale of tens of millions of years, it can’t just be a remnant of the atmosphere present when Titan itself was formed, and it must be replenished quite regularly," said Tobie.

"According to our model, during the last outgassing episode, the dissociation of the methane clathrate and hence release of methane are induced by thermal anomalies within the icy crust, which are generated by crystallisation in the internal ocean," said Tobie.

"As this crystallisation started only relatively recently (500 to 1000 million years ago), we expect that the ammonia-water ocean is still present few tens of kilometres below the surface and that methane outgassing is still operating. Even though the outgassing rate is expected to decline now (it peaked about 500 million years ago), release of methane through cryovolcanic eruptions should still occur on Titan," explained Tobie.

"Parts of the clathrate crust might be warmed from time to time by ‘cryovolcanic’ activity on the moon, causing it to release its methane into the atmosphere. These outbursts could produce temporary flows of liquid methane on the surface, accounting for the river-like features seen on Titan’s surface.

"Cassini’s instruments, in particular its Visible and Infrared Mapping Spectrometer (VIMS), should detect an increasing number of cryovolcanic features and, if we are lucky, may eventually detect eruptions of methane," added Tobie.

If they are right, say the researchers, then Cassini and future missions to Titan should also be able to detect the existence of their possible subsurface liquid water-ammonia ocean.

Later in the mission, Cassini itself will make measurements that will confirm (or not) the presence of the internal water ocean, and also the existence of a rocky core.

Jean-Pierre Lebreton | EurekAlert!
Further information:
http://www.esa.int/esaSC/SEM4BQMVGJE_index_0.html

More articles from Earth Sciences:

nachricht Supercomputing helps researchers understand Earth's interior
23.05.2017 | University of Illinois College of Liberal Arts & Sciences

nachricht How is climate change affecting fauna in the Arctic?
22.05.2017 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

Im Focus: Using graphene to create quantum bits

In the race to produce a quantum computer, a number of projects are seeking a way to create quantum bits -- or qubits -- that are stable, meaning they are not much affected by changes in their environment. This normally needs highly nonlinear non-dissipative elements capable of functioning at very low temperatures.

In pursuit of this goal, researchers at EPFL's Laboratory of Photonics and Quantum Measurements LPQM (STI/SB), have investigated a nonlinear graphene-based...

Im Focus: Bacteria harness the lotus effect to protect themselves

Biofilms: Researchers find the causes of water-repelling properties

Dental plaque and the viscous brown slime in drainpipes are two familiar examples of bacterial biofilms. Removing such bacterial depositions from surfaces is...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

Innovation 4.0: Shaping a humane fourth industrial revolution

17.05.2017 | Event News

 
Latest News

Scientists propose synestia, a new type of planetary object

23.05.2017 | Physics and Astronomy

Zap! Graphene is bad news for bacteria

23.05.2017 | Life Sciences

Medical gamma-ray camera is now palm-sized

23.05.2017 | Medical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>