* Astronomy

Blobrana · L

RE: Mars methane

Blobrana · L

Mars methane linked to meteorites

Tiny amounts of methane in the Martian atmosphere may come not from living things, but from meteorites on the red planet's surface, the latest findings suggest.
An international team of scientists show for the first time that meteorites continually bombarding Mars contain enough carbon compounds to generate methane when exposed to ultraviolet radiation.
The findings could help inform future missions searching for Martian life.
Read more

Blobrana · L

Did 'martian' methane signal come from Earth?

Claims that Mars's atmosphere contains methane, which have fuelled speculations that the planet hosts life, may be premature.
A key piece of evidence for methane on Mars may actually be due to Earth-based methane, say researchers led by Kevin Zahnle of the NASA Ames Research Centre in Moffett Field, California.
Read more

Blobrana · L

Mars Methane Lasts Less than a Year

Methane in the atmosphere of Mars lasts less than a year, according to a study by Italian scientists. Sergio Fonti (Universita del Salento) and Giuseppe Marzo (NASA Ames) have used observations from NASA's Mars Global Surveyor spacecraft to track the evolution of the gas over three martian years. They presented their results at the European Planetary Science Congress in Rome on Tuesday 21st September.
Read more

Blobrana · L

New Model Is Proposed to Explain Absence of Organic Compounds on Surface of Mars

The ongoing search for evidence of past or present life on Mars includes efforts to identify organic compounds such as proteins in Martian soil, but their absence to date remains a mystery. A new theory to explain what happens to these carbon-based molecules is presented in an article published in Astrobiology, a peer-reviewed journal published by Mary Ann Liebert, Inc. The article is available free online at www.liebertpub.com/ast.
Unlike on Earth, where plants and other organisms convert carbon dioxide and water into organic compounds via photosynthesis, the authors propose that the opposite happens on the surface of Mars. The iron oxides that make up Martian soil and give the planet its distinctive red colour are photocatalysts. They use energy from ultraviolet light absorbed through the thin Martian atmosphere to oxidize carbon-containing organic molecules trapped in soil particles, converting them to carbon dioxide and gases such as methane.
Read more

Blobrana · L

The surprising discovery of methane in Mars's atmosphere could be a sign of life there. Researchers are now working out how to find its source.
For the past decade, NASA's mantra for exploring Mars has been to 'follow the water'. The agency based its aqueous obsession on the idea that finding evidence of past or present water would yield clues to whether life once graced the planet - or still exists there.
Source

Blobrana · L

The methane found on Mars is not brought to the planet by meteor strikes, scientists say.
Meteoritic material subjected to high temperatures did not release enough methane to account for the amount believed to be released on Mars.
The researchers argue that the methane must therefore be created by geologic or chemical processes, or it is a by-product of microbial life.

Read more

Blobrana · L

Scientists have ruled out the possibility that methane is delivered to Mars by meteorites, raising fresh hopes that the gas might be generated by life on the red planet, in research published tomorrow (Wednesday 9 December 2009) in Earth and Planetary Science Letters.
Methane has a short lifetime of just a few hundred years on Mars because it is constantly being depleted by a chemical reaction in the planet's atmosphere, caused by sunlight. Scientists analysing data from telescopic observations and unmanned space missions have discovered that methane on Mars is being constantly replenished by an unknown source and they are keen to uncover how the levels of methane are being topped up.

Source: Imperial College London

Blobrana · L

Mars, methane and mysteries
Mars may not be as dormant as scientists once thought. The 2004 discovery of methane means that either there is life on Mars, or that volcanic activity continues to generate heat below the martian surface. ESA plans to find out which it is. Either outcome is big news for a planet once thought to be biologically and geologically inactive.
The methane mystery started soon after December 2003, when ESA's Mars Express arrived in orbit around the red planet. As the Planetary Fourier Spectrometer (PFS) began taking data, Vittorio Formisano, Istituto di Fisica dello Spazio Interplanetario CNR, Rome, and the rest of the instrument team saw a puzzling signal. As well as the atmospheric gases they were anticipating, such as carbon monoxide and water vapour, they also saw methane.

Read more

Blobrana · L

Since the discovery of its presence in the Martian atmosphere, methane has remained an intriguing atmospheric component which source (either of biotic or abiotic origin) is not yet fully understood. The recently reported variations in the concentration of atmospheric methane have proven difficult to explain with 3-D numerical models of the atmosphere that include the known chemical and physical processes. In a paper published this week in Nature, Franck Lefevre and Francois Forget present their study to derive the implications of the observed methane concentrations on Mars and their variability. They conclude that there needs to be both an intense localised source of methane and a destruction mechanism that is much more efficient than the known atmospheric processes that break down methane. Further, if this efficient destruction of methane occurs only close to the surface, these findings imply a very harsh environment for organic molecules to survive on the surface of Mars.

Read more