Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Methane on Mars is not an indication for life

31.05.2012
Intense UV radiation on the red planet releases methane from organic materials which meteorites transport onto its surface

It was a sensation when scientists discovered methane in Mars’ atmosphere nine years ago. Many saw the presence of the gas as a clear indication of life on the inhospitable planet, as on Earth methane is produced predominantly by biological processes.


Methane concentration on Mars: The graphics shows the calculated methane concentrations in parts per billion (ppb) on Mars during the summer in the northern hemisphere. Violet and blue indicate small methane, red areas indicate large amounts.
Source: NASA

Others assumed geological processes, such as volcanoes, to be the cause. What has been missing until now is proof of where the methane actually comes from, however. Researchers at the Max Planck Institute for Chemistry in Mainz and the universities in Utrecht and Edinburgh have now been able to show that methane escapes from a meteorite if it is irradiated with ultraviolet light under Martian conditions.

Since meteorites and interplanetary dust from space, which carry along carbonaceous compounds, continuously impact on the Martian surface, the researchers conclude that high-energy UV radiation triggers the release of methane from the meteorites.

Since scientists identified larger quantities of methane in the Martian atmosphere in 2003, there has been much speculation about its source. The best-known hypothesis states that microorganisms produce the methane, and is thus an indication of life on the red planet. Another hypothesis assumes the source to be geological methane sources in Mars’ interior. To date, none of the theories has been able to conclusively explain the large quantity of 200 to 300 tonnes of methane annually which are produced on Mars, according to projections.

Without an expedition to Mars and with nothing more than a meteorite to help them, researchers at the Max Planck Institute for Chemistry in Mainz and the universities in Utrecht and Edinburgh have now found a major source. “Methane is produced from innumerable, small micro-meteorites and interplanetary dust particles that land on the Martian surface from space,” explains Frank Keppler, lead author of the study now published in the research journal Nature. “The energy is provided by the extremely intense ultraviolet radiation,” adds the atmospheric chemist.

UV light decomposes carbon compounds in meteoritic matter

Unlike Earth, Mars has no protective ozone layer which could absorb most of the UV radiation from space. Moreover, the Martian atmosphere is very thin, so that a significantly smaller portion of the meteoritic material burns up in the atmosphere compared to Earth.

Together with colleagues from Great Britain and the Netherlands, the researchers from Mainz irradiated samples of the Murchison meteorite with ultraviolet light. “The meteorite contains several percent carbon and has a similar chemical composition to most of the meteoritic matter that lands on Mars,” says the cosmochemist Ulrich Ott. The 4.6 billion-year-old meteorite fell to Earth in 1969 in the Australian town of Murchison. The researchers selected conditions identical to those on Mars for the UV irradiation, which caused considerable quantities of methane to escape from the meteorite almost immediately. Their conclusion: carbonaceous compounds in the meteoritic matter are decomposed by the high-energy UV radiation, and methane molecules are formed in the process.

The methane production from meteorites depends on temperature

Since the temperature on the red planet varies from minus 143 degrees Celsius at the poles to plus 17 degrees Celsius at Mars’ equator, the scientists also investigated the meteoritic samples at appropriate temperatures. The warmer it became, the more methane was released by the meteoritic fragments. This temperature dependence also agrees with the different methane concentrations at different locations in the Martian atmosphere. In infrared spectra, the largest concentration of methane was found in the equatorial region, the warmest place on Mars, relatively speaking.

The results obtained by Frank Keppler’s team should bring “down to earth” all those who firmly believe in the biological origin of methane. The researchers cannot fully exclude the hypothesis of Martian microbes, however, because, although the process found here is inevitable, it is quite possible that further processes contribute to methane production. The researchers hope that Curiosity, the Mars Rover that NASA expects to land on our neighbouring planet at the beginning of August, will provide more details on the formation of methane, and maybe even final clarification as to whether there is life on Mars.

Original publication
Ultraviolet radiation induced methane emissions from meteorites and the Martian atmosphere
Frank Keppler, Ivan Vigano, Andy McLeod, Ulrich Ott, Marion Früchtl, Thomas Röckmann

Nature, 31. Mai 2012; DOI 10.1038/nature11203 (2012)

Contact
Dr. Frank Keppler
Max Planck Institut for Chemistry
Phone: +49-6131-305 4800
E-mail: frank.keppler@mpic.de
Dr. Ulrich Ott
Max Planck Institut for Chemistry
Phone: +49-160-5467230
E-mail: uli.ott@mpic.de

Dr. Wolfgang Huisl | Max-Planck-Institut
Further information:
http://www.mpic.de

More articles from Physics and Astronomy:

nachricht Further Improvement of Qubit Lifetime for Quantum Computers
09.12.2016 | Forschungszentrum Jülich

nachricht Electron highway inside crystal
09.12.2016 | Julius-Maximilians-Universität Würzburg

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

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

Im Focus: Electron highway inside crystal

Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.

Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Researchers identify potentially druggable mutant p53 proteins that promote cancer growth

09.12.2016 | Life Sciences

Scientists produce a new roadmap for guiding development & conservation in the Amazon

09.12.2016 | Ecology, The Environment and Conservation

Satellites, airport visibility readings shed light on troops' exposure to air pollution

09.12.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>