Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Life's molecules could lie within reach of Mars Curiosity rover

06.07.2012
Stick a shovel in the ground and scoop. That's about how deep scientists need to go in order to find evidence for ancient life on Mars, if there is any to be found, a new study suggests. That's within reach of Curiosity, the Mars Science Laboratory rover expected to land on the Red Planet next month.
The new findings, which suggest optimal depths and locations to probe for organic molecules like those that compose living organisms as we know them, could help the newest Mars rover scout for evidence of life beneath the surface and within rocks. The results suggest that, should Mars harbor simple organic molecules, NASA's prospects for discovering them during Curiosity's explorations are better than previously thought, said Alexander Pavlov of the NASA Goddard Space Flight Center in Greenbelt, Maryland, lead author of the study.

While these simple molecules could provide evidence of ancient Martian life, they could also stem from other sources like meteorites and volcanoes. Complex organic molecules could hint more strongly at the possibility of past life on the planet. These molecules, made up of 10 or more carbon atoms, could resemble known building blocks of life such as the amino acids that make up proteins.

Although complex carbon structures are trickier to find because they're more vulnerable to cosmic radiation that continuously bombards and penetrates the surface of the Red Planet, the new research by Pavlov and his colleagues provides suggestions for where to start looking. The amounts of radiation that rock and soil is exposed to over time, and how deep that radiation penetrates – an indicator of how deep a rover would have to sample to find intact organic molecules – is a subject of ongoing research.

The scientists report that chances of finding these molecules in the first 2 centimeters (0.8 inches) of Martian soil is close to zero. That top layer, they calculate, will absorb a total of 500 million grays of cosmic radiation over the course of one billion years – capable of destroying all organic material. A mere 50 grays, absorbed immediately or over time, would cause almost certain death to a human.

However, within 5 to 10 centimeters (2 to 4 inches) beneath the surface, the amount of radiation reduces tenfold, to 50 million grays. Although that's still extreme, the team reports that simple organic molecules, such as a single formaldehyde molecule, could exist at this depth – and in some places, specifically young craters, the complex building blocks of life could remain as well.
The study is scheduled to be published 7 July in Geophysical Research Letters, a journal of the American Geophysical Union.

"Right now the challenge is that past Martian landers haven't seen any organic material whatsoever," Pavlov said. "We know that organic molecules have to be there but we can't find any of them in the soil."

As Mars revolves around the Sun, it is constantly bombarded by very small meteors and interplanetary dust particles, which have plenty of organic compounds in them, Pavlov said. Therefore, over time they would have accumulated at the Martian surface.

The Mars Science Laboratory is the newest and largest of NASA's Martian landers and is scheduled to touch down August 2012. Curiosity doesn't have a shovel but, equipped with drilling technology, it will collect, store, and analyze samples of Martian material down to 5 centimeters below the surface of rock and soil. Past Martian rovers have only collected loose soil atop the surface that has been directly exposed to cosmic radiation, making the possibility for detecting organic molecules exceedingly slim.

When evaluating how deep organic molecules might persist beneath the surface, previous studies have mainly focused on the maximum depth, approximately 1.5 meters (5 feet), that cosmic radiation reaches because beyond that point organic molecules could survive, unharmed, for billions of years, Pavlov said. However, drilling to 1.5 meters or deeper is currently too expensive to engineer for a Martian rover.

So the team focused on more attainable depths – the first 20 cm (8 in) below the surface. They modeled the complex scenario of cosmic ray accumulation and its effects on organic molecules using a collection of important variables, including Martian rock and soil composition, changes in the planet's atmospheric density over time, and cosmic rays' various energy levels.

In addition to the finding that some simple carbon-containing molecules could exist within 10 cm (4 in) depth, the scientists emphasize that certain regions on Mars may have radiation levels far lower than 50 million grays near the surface – and so more complex molecules like amino acids could remain intact.

In order to find these molecules within the rover's drilling range (1 to 5 cm), the scientists found the best bet is to look at "fresh" craters that are no more than 10 million years old, unlike past expeditionary sites that mainly sampled from landscapes undisturbed for billions of years.

Compared to Martian landscapes undisturbed for one billion years or more, relatively young craters exhibit freshly exposed rock and soil that was once deeper beneath the surface. . The new research indicates that this material will have been near the surface for a short enough period of time that it's overall exposure to harmful radiation would not have been enough to wipe out organic molecules.

"When you have a chance to drill, don't waste it on perfectly preserved (landscapes)," Pavlov said. "You want to go to fresh craters because there's probably a better chance to detect complex organic molecules. Let Nature work for you."

Lewis Dartnell, a postdoctoral researcher at the University College London in the U.K., said the paper was a nice study that combined results from other studies with the latest radiation modeling. Dartnell was not part of the study, but has published previous work involving effects of cosmic radiation on the Martian surface.

"The next logical step," Dartnell said, "is to actually experiment and have a radiation source hit amino acids with radiation of similar energies as cosmic rays and determine how quickly those amino acids are destroyed because models can only do so much."

Curiosity is set to land in Gale crater – the same crater where the Spirit rover landed in 2004– on August 6. Whether this 3.5-billion-year-old crater has fresher craters within it is uncertain. However, Pavlov hopes that his team's findings will at least help guide NASA on where to drill once the rover has landed and influence where future generations of rover landers will touch down.

Notes for Journalists
Journalists and public information officers (PIOs) of educational and scientific institutions who have registered with AGU can download a PDF copy of this paper in press by clicking on this link: http://dx.doi.org/10.1029/2012GL052166

Or, you may order a copy of the final paper by emailing your request to Kate Ramsayer at kramsayer@agu.org. Please provide your name, the name of your publication, and your phone number.

Neither the paper nor this press release are under embargo.

Title: "Degradation of the organic molecules in the shallow subsurface of Mars due to irradiation by cosmic rays"

Authors: Alexander A. Pavlov: Planetary Environments Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD, USA;

G. Vasilyev: Laboratory of Mass Spectrometry, Ioffe Physico-Technical Institute of Russian Academy of Sciences, St. Petersburg, Russia;

V. M. Ostryakov: St. Petersburg State Technical University, St. Petersburg, Russia;

A. K. Pavlov: Laboratory of Mass Spectrometry, Ioffe Physico-Technical Institute of Russian Academy of Sciences, St. Petersburg, Russia;

P. Mahaffy: Planetary Environments Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD, USA.

Contact information for the authors: Alexander A. Pavlov, Email: alexander.pavlov@nasa.gov, Telephone: 301-614-5945

Kate Ramsayer | EurekAlert!
Further information:
http://www.agu.org

More articles from Earth Sciences:

nachricht NASA looks to solar eclipse to help understand Earth's energy system
21.07.2017 | NASA/Goddard Space Flight Center

nachricht Scientists shed light on carbon's descent into the deep Earth
19.07.2017 | European Synchrotron Radiation Facility

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Manipulating Electron Spins Without Loss of Information

Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.

For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...

Im Focus: The proton precisely weighted

What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.

To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...

Im Focus: On the way to a biological alternative

A bacterial enzyme enables reactions that open up alternatives to key industrial chemical processes

The research team of Prof. Dr. Oliver Einsle at the University of Freiburg's Institute of Biochemistry has long been exploring the functioning of nitrogenase....

Im Focus: The 1 trillion tonne iceberg

Larsen C Ice Shelf rift finally breaks through

A one trillion tonne iceberg - one of the biggest ever recorded -- has calved away from the Larsen C Ice Shelf in Antarctica, after a rift in the ice,...

Im Focus: Laser-cooled ions contribute to better understanding of friction

Physics supports biology: Researchers from PTB have developed a model system to investigate friction phenomena with atomic precision

Friction: what you want from car brakes, otherwise rather a nuisance. In any case, it is useful to know as precisely as possible how friction phenomena arise –...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Closing the Sustainability Circle: Protection of Food with Biobased Materials

21.07.2017 | Event News

»We are bringing Additive Manufacturing to SMEs«

19.07.2017 | Event News

The technology with a feel for feelings

12.07.2017 | Event News

 
Latest News

NASA looks to solar eclipse to help understand Earth's energy system

21.07.2017 | Earth Sciences

Stanford researchers develop a new type of soft, growing robot

21.07.2017 | Power and Electrical Engineering

Vortex photons from electrons in circular motion

21.07.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>