Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Curiosity confirms origins of Martian meteorites

17.10.2013
Earth’s most eminent emissary to Mars has just proven that those rare Martian visitors that sometimes drop in on Earth — a.k.a. Martian meteorites — really are from the Red Planet.

A key new measurement of Mars’ atmosphere by NASA’s Curiosity rover provides the most definitive evidence yet of the origins of Mars meteorites while at the same time providing a way to rule out Martian origins of other meteorites.


Martian meteorite
Scientists identified meteorites, such as this one nicknamed “Black Beauty,” as Martian in origin. NASA

The new measurement is a high-precision count of two forms of argon gas—Argon-36 and Argon-38–accomplished by the Sample Analysis at Mars (SAM) instrument on Curiosity. These lighter and heavier forms, or isotopes, of argon exist naturally throughout the solar system. But on Mars the ratio of light to heavy argon is skewed because a lot of that planet’s original atmosphere was lost to space, with the lighter form of argon being taken away more readily because it rises to the top of the atmosphere more easily and requires less energy to escape. That’s left the Martian atmosphere relatively enriched in the heavier Argon-38.

Years of past analyses by Earth-bound scientists of gas bubbles trapped inside Martian meteorites had already narrowed the Martian argon ratio to between 3.6 and 4.5 (that is 3.6 to 4.5 atoms of Argon-36 to every one Argon-38) with the supposed Martian “atmospheric” value near four. Measurements by NASA’s Viking landers in the 1970’s put the Martian atmospheric ratio in the range of four to seven. The new SAM direct measurement on Mars now pins down the correct argon ratio at 4.2.

“We really nailed it,” said Sushil Atreya of the University of Michigan, Ann Arbor, the lead author of a paper reporting the finding today in Geophysical Research Letters, a journal of the American Geophysical Union. “This direct reading from Mars settles the case with all Martian meteorites,” he said.

One of the reasons scientists have been so interested in the argon ratio in Martian meteorites is that it was – before Curiosity – the best measure of how much atmosphere Mars has lost since the planet’s earlier, wetter, warmer days billions of years ago. Figuring out the planet’s atmospheric loss would enable scientists to better understand how Mars transformed from a once water-rich planet more like our own to the today’s drier, colder and less hospitable world.

Had Mars held onto its entire atmosphere and its original argon, Atreya explained, its ratio of the gas would be the same as that of the Sun and Jupiter. They have so much gravity that isotopes can’t preferentially escape, so their argon ratio – which is 5.5 – represents that of the primordial solar system.

While argon comprises only a tiny fraction of the gases lost to space from Mars, it is special because it’s a noble gas. That means the gas is inert, not reacting with other elements or compounds, and therefore a more straightforward tracer of the history of the Martian atmosphere.

“Other isotopes measured by SAM on Curiosity also support the loss of atmosphere, but none so directly as argon,” said Atreya. “Argon is the clearest signature of atmospheric loss because it’s chemically inert and does not interact or exchange with the Martian surface or the interior. This was a key measurement that we wanted to carry out on SAM.”

NASA’s Jet Propulsion Laboratory, Pasadena, Calif., manages the Curiosity mission for NASA’s Science Mission Directorate, Washington. The SAM investigation on the rover is managed by NASA Goddard Space Flight Center, Greenbelt, Md.

Journalists and public information officers (PIOs) of educational and scientific institutions who have registered with AGU can download a PDF copy of this early view article by clicking on this link: http://onlinelibrary.wiley.com/doi/10.1002/2013GL057763/abstract

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

Title

“Primordial argon isotope fractionation in the atmosphere of Mars measured by the SAM instrument on Curiosity, and implications for atmospheric loss”

Sushil K. Atreya and Michael H. Wong
Department of Atmospheric, Oceanic and Space Sciences, The University of Michigan, Ann Arbor, Mich.;
Melissa G. Trainer, Heather B. Franz, Charles A. Malespin, Paul R. Mahaffy, Pamela G. Conrad and Anna E.
Brunner
Goddard Space Flight Center, Greenbelt, Md.;
K. Manning
Concordia College, Moorhead, Minn.;
Laurie A. Leshin
School of Science, Rensselaer Polytechnic Institute, Troy, N.Y.;
John H. Jones
NASA Johnson Space Center, Houston, Tx.;
Christopher R. Webster
Jet Propulsion Laboratory, California Institute of Technology, Pasadena, Calif.;
Tobias C. Owen
University of Hawaii, Honolulu, Hawaii;
Robert O. Pepin
University of Minnesota, Minneapolis, Minn.;
R. Navarro-González
Universidad Nacional Autónoma de México, Ciudad Universitaria, Apartado, México.

Contact information for the authors:

Sushil Atreya, Phone: +1 (734) 936-0489, Email: atreya@umich.edu

Media Contacts

Peter Weiss
Public Information Manager
Phone: +1 202 777 7507
E-mail: Pweiss@agu.org
Joan Buhrman
Strategic Communications Manager
Phone: +1 202 777 7509
E-mail: JBuhrman@agu.org
Mary Catherine Adams
Public Information Specialist
Phone: +1 202 777 7530
E-mail: MCAdams@agu.org
Phone: +1 (800) 966 2481
(Toll free in North America)
Fax: +1 202 328 0566

Peter Weiss | American Geophysical Union
Further information:
http://www.agu.org
http://news.agu.org/press-release/curiosity-confirms-origins-of-martian-meteorites/

More articles from Earth Sciences:

nachricht Multi-year submarine-canyon study challenges textbook theories about turbidity currents
12.12.2017 | Monterey Bay Aquarium Research Institute

nachricht How do megacities impact coastal seas? Searching for evidence in Chinese marginal seas
11.12.2017 | Leibniz-Institut für Ostseeforschung Warnemünde

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Long-lived storage of a photonic qubit for worldwide teleportation

MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.

Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

Im Focus: Successful Mechanical Testing of Nanowires

With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong

Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

Long-lived storage of a photonic qubit for worldwide teleportation

12.12.2017 | Physics and Astronomy

Multi-year submarine-canyon study challenges textbook theories about turbidity currents

12.12.2017 | Earth Sciences

Electromagnetic water cloak eliminates drag and wake

12.12.2017 | Power and Electrical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>