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 New proton record: Researchers measure magnetic moment with greatest possible precision
24.11.2017 | Johannes Gutenberg-Universität Mainz

nachricht Enhancing the quantum sensing capabilities of diamond
23.11.2017 | The Hebrew University of Jerusalem

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: New proton record: Researchers measure magnetic moment with greatest possible precision

High-precision measurement of the g-factor eleven times more precise than before / Results indicate a strong similarity between protons and antiprotons

The magnetic moment of an individual proton is inconceivably small, but can still be quantified. The basis for undertaking this measurement was laid over ten...

Im Focus: Frictional Heat Powers Hydrothermal Activity on Enceladus

Computer simulation shows how the icy moon heats water in a porous rock core

Heat from the friction of rocks caused by tidal forces could be the “engine” for the hydrothermal activity on Saturn's moon Enceladus. This presupposes that...

Im Focus: Nanoparticles help with malaria diagnosis – new rapid test in development

The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.

Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Lightning, with a chance of antimatter

24.11.2017 | Earth Sciences

A huge hydrogen generator at the Earth's core-mantle boundary

24.11.2017 | Earth Sciences

Scientists find why CP El Niño is harder to predict than EP El Niño

24.11.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>