Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

How Martian Winds Make Rocks Walk

09.01.2009
Rocks on Mars are on the move, rolling into the wind and forming organized patterns, according to new research.

The new finding counters the previous explanation of the evenly spaced arrangement of small rocks on Mars. That explanation suggested the rocks were picked up and carried downwind by extreme high-speed winds thought to occur on Mars in the past.

Images taken by the Mars Exploration Rover Spirit show small rocks regularly spaced about 5 to 7 centimeters apart on the intercrater plains between Lahontan Crater and the Columbia Hills.

Although Mars is a windy planet, it would be difficult for the wind to carry the small rocks, which range in size from a quarter to a softball, said Jon D. Pelletier, associate professor of geosciences at The University of Arizona in Tucson.

Pelletier and his colleagues suggest that wind blows sand away from the front of the rock, creating a pit, and then deposits that sand behind the rock, creating a hill.

The rock then rolls forward into the pit, moving into the wind, he said.

As long as the wind continues to blow, the process is repeated and the rocks move forward.

This explanation does not require extreme winds, Pelletier said.

"You get this happening five, 10, 20 times then you start to really move these things around," he said. "They can move many times their diameter."

The process is nearly the same with a cluster of rocks.

However, with a cluster of rocks, those in the front of the group shield those in the middle or on the edges from the wind, Pelletier said.

Because the middle and outer rocks are not directly hit by the wind, the wind creates pits to the sides of those rocks. Therefore, they roll to the side, not directly into the wind, and the cluster begins to spread out.

Pelletier, Andrew L. Leier of the University of Calgary in Alberta, Canada, and James R. Steidtmann of the University of Wyoming in Laramie report their findings in the paper, "Wind-Driven Reorganization of Coarse Clasts on the Surface of Mars." The paper is in the January issue of the journal Geology.

When Leier was a graduate student at the UA, he told Pelletier about an experiment on the upwind migration of rocks that Steidtmann, Leier's thesis advisor, had conducted.

Steidtmann had studied upwind migration about 30 years ago. He used a wind tunnel to see how pebbles on sand moved in the wind. Steidtmann's research showed that the rocks moved upwind and that over time, a regular pattern emerged.

Pelletier wasn't sure how he could use the idea.

Some time later, while attending a lecture that showed pictures of uniformly organized rocks on Mars, Pelletier recalled his conversations with Leier about Steidtmann's experiments -- and it all came together.

To investigate the regular patterns of the rocks on Mars, Pelletier combined three standard numerical computer models. The first modeled air flow, the second modeled erosion and deposition of sand and the third modeled the rocks' movement, he said.

"We can model it on the computer to try to get a better sense of what's actually happening and to provide another sort of documentation or justification for the idea," he said.

Pelletier was the first to combine the three standard models and apply them to this new problem.

He also conducted what is known as a Monte Carlo simulation, which applies his combination numerical model over and over to a random pattern of rocks to see how the rocks ultimately end up.

Pelletier ran the simulation 1,000 times. The rocks ended up into a regular pattern 90 percent of the time, he said.

As an independent verification, he also compared the pattern predicted by the numerical model to the distances between each rock and its nearest neighbor in the Mars images. The patterns of the Martian rocks matched what the model predicted.

Pelletier said upwind migration of rocks also occurs on Earth.

Co-author Leier wrote in an e-mail, "Something as seemingly mundane as the distribution of rocks on a sandy, wind-blown surface can actually be used to tell us a lot about how wind-related processes operate on a place as familiar as the Earth and as alien as Mars."

However, because plants and animals can alter wind patterns and rearrange rocks, it is much more difficult to study this process on Earth, Pelletier said.

Of Mars' mysterious walking rocks, he said, "This is a neat problem, but there are bigger fish to fry."

Pelletier plans to apply the same numerical models to larger features on Mars such as sand dunes and wind-sculpted valleys and ridges called "yardangs."

He said understanding the climate history of other planets and where those climates went awry can help in understanding our own climate system.

This release was written by University of Arizona NASA Space Grant Intern Megan Levardo.

Researcher Contact Information:
Jon D. Pelletier
(520) 626-2126
jdpellet@email.arizona.edu

Mari N. Jensen | University of Arizona
Further information:
http://geomorphology.geo.arizona.edu/
http://marsrovers.nasa.gov/home/index.html

More articles from Physics and Astronomy:

nachricht Climate cycles may explain how running water carved Mars' surface features
02.12.2016 | Penn State

nachricht What do Netflix, Google and planetary systems have in common?
02.12.2016 | University of Toronto

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: 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...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

Im Focus: Fraunhofer ISE Develops Highly Compact, High Frequency DC/DC Converter for Aviation

The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...

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

UTSA study describes new minimally invasive device to treat cancer and other illnesses

02.12.2016 | Medical Engineering

Plasma-zapping process could yield trans fat-free soybean oil product

02.12.2016 | Agricultural and Forestry Science

What do Netflix, Google and planetary systems have in common?

02.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>