News and Updates

08/01/2014

Ravi Lucas DeFilippo 9/1/1986 - 8/1/2010

Ravi DeFilippo, one of SESE's brightest and most promising alumni, was killed on August 1, 2010 in a mining accident near Mount Toromocho, Peru.

Four years later, Ravi’s brief, brilliant life continues to inspire us. We embrace the world he loved by finding passion in our studies, work, travel and love – just as Ravi did. “Mi deber es vivir, morir, vivir.”

If you would like to contribute a memorial donation, please send to:
Attention: Sonya Lindquist, ASU/School of Earth & Space Exploration, Ravi DeFilippo Geology Field Camp Scholarship,
P.O. Box 876004, Tempe, AZ 85287 – 6004

Or, if you prefer, you may donate online to: www.asufoundation.org/DeFilippoFieldCamp

 

07/31/2014

Arizona State University has been selected by NASA to design, deliver and oversee the Mastcam-Z imaging investigation, a pair of color panoramic zoom cameras, on the next rover mission to be launched to the surface of Mars in 2020. Jim Bell, a professor in ASU’s School of Earth and Space Exploration, will be the principal investigator overseeing the investigation.

NASA has selected the instruments that will be carried aboard the Mars 2020 mission, a roving laboratory based on the highly successful Curiosity rover. The instruments were competitively selected from 58 proposals submitted, two times the average number of proposals submitted for instrument competitions in the recent past and an indicator of the extraordinary interest in exploration of the Red Planet.

The Mars 2020 rover will be designed to seek signs of past life on Mars, to collect and store samples that could be returned to Earth in the future, and to test new technology to benefit future robotic and human exploration of Mars. The instruments onboard will help to build upon the many discoveries from the Curiosity Mars rover and the two Mars Exploration Rovers (Spirit and Opportunity) and will be the critical next step in NASA’s strategic program of exploring the Red Planet.

Bell will oversee an international science team responsible for creating and operating the cameras on NASA’s next, yet-to-be-named, Mars rover. Bell has been responsible for the science imaging systems onboard the NASA Mars Exploration Rovers Spirit and Opportunity, and is the deputy P.I. of the color cameras on the Curiosity rover.

“These cameras will be the main eyes of NASA’s next rover,” says Bell.

The imaging system ASU will deliver is a pair of multispectral, stereoscopic cameras that will be an enhanced descendant of Curiosity’s successful imaging instrument called Mastcam. Mastcam-Z will be comprised of two zoom camera heads to be mounted on the rover’s remote sensing mast. This matched pair of zoom cameras will each provide broad-band red/green/blue (RGB) color imaging, as well as narrow-band visible to short-wave near-infrared multispectral capability.

Mastcam-Z will have all of the capabilities of Curiosity’s imaging instrument, but is augmented by a 3.6:1 zoom feature capable of resolving features about 1 millimeter in size in the near field and about 3-4 centimeters in size at 100 meter distance.

“The cameras that we will build and use on Mars are based on Curiosity’s cameras but with enhanced capabilities,” explains Bell. “Specifically we will be able to use our zoom capability to allow us to play a much more significant role in rover driving and target selection.”

Mastcam-Z’s imaging will permit the science team to piece together the geologic history of the site—the stratigraphy of rock outcrops and the regolith, as well as to constrain the types of rocks present. The cameras will also document dynamic processes and events via video (such as dust devils, cloud motions, and astronomical phenomena, as well as activities related to driving, sampling, and caching), observe the atmosphere, and contribute to rover navigation and target selection for investigations by the coring/caching system, as well as other instruments.

Bell’s large international science team will include Mark Robinson, School of Earth and Space Exploration professor and principal investigator for the imaging system on board NASA’s Lunar Reconnaissance Orbiter Camera. Robinson brings significant experience in planetary geology and spacecraft imaging and will be responsible for characterizing the regolith from Mastcam‐Z images and assisting with camera calibration and mission operations.

In addition, Bell intends to involve a significant number of staff, undergraduate students, and graduate students in the mission. For example, SESE Research Scientist Craig Hardgrove and Technology Support Analyst Austin Godber are slated to play leading roles in the design, testing, and operations of the Mastcam-Z investigation.

Mastcam-Z remote instrument operations will be directed from the ASU Science Operations Center (SOC), housed in the Mission Operations Center located in the Interdisciplinary Science and Technology Building IV on the ASU campus. ASU faculty, staff, and students will work closely with mission engineering leads at NASA's Jet Propulsion Laboratory in Pasadena, Calif.

“We are very excited about playing such a critical role in NASA’s next Mars rover. And we are especially excited because this rover will be the first step in NASA’s Mars rover sample return mission,” says Bell. “We are eager are to play a role in the selection of the first Martian samples for eventual return to Earth.”

###

Caption: Jim Bell, a professor in ASU’s School of Earth and Space Exploration, stands in front of a model of Mars Science Laboratory (MSL, aka Curiosity rover) in ISTB 4. ASU has been selected by NASA to design, deliver and oversee the Mastcam-Z imaging investigation, a pair of color panoramic zoom cameras, on the next rover mission to be launched to the surface of Mars in 2020. Bell will be the principal investigator overseeing the investigation. Photo by: Andy DeLisle

(Nikki Cassis)

 

07/31/2014

The Universe is home to a variety of exotic objects and beautiful phenomena, some of which can generate almost inconceivable amounts of energy. ASU Regents’ Professor Sumner Starrfield is part of a team that used the Large Area Telescope (LAT) onboard NASA’s Fermi Gamma-ray Space Telescope satellite to discover very high energy gamma rays (the most energetic form of light) being emitted by an exploding star. The surprising discovery dispels the long-held idea that classical nova explosions are not powerful enough to produce such high-energy radiation.

In March 2010, scientists using the LAT reported a surprising discovery: detection of gamma rays that appeared to come from a nova, V407 Cygni. The LAT, in orbit around the Earth, views ∼20% of the sky instantaneously and the entire sky every three hours. It is the most sensitive gamma-ray space telescope ever flown.

A nova is observed as a sudden, short-lived rapid increase in the brightness of an otherwise inconspicuous star. It results from runaway thermonuclear explosions that typically take place in a binary system on the surface of a white dwarf fueled by mass from a companion star. The outburst occurs when a white dwarf erupts in an enormous thermonuclear explosion. The explosion is equivalent to about 100,000 times the energy that the sun gives off every year. Unlike supernovas, novae do not result in the destruction of their stars.

Although novae produce bright optical events, they had not previously been considered as potential sources of high energy gamma rays since they are not predicted to accelerate particles to the required energies (very nearly the speed of light). Few cosmic marvels can accelerate particles to the energies required to generate gamma rays, billions of times more energetic than the type of light visible to our eyes. Researchers had expected and seen X-rays from the resulting waves of expanding gas in prior novae.

The finding overturned the notion that novae explosions lack the power to emit such high-energy radiation. Subsequently in June 2012, two more novae were detected with the LAT, Nova Sco 2012 and Nova Mon 2012, thus heralding novae as a new gamma-ray source class.

These findings are published in the August 1 issue of the journal Science with Teddy Cheung, an astrophysicist at the Naval Research Laboratory in Washington, as the lead author.

“This was a completely unexpected discovery and we still don’t understand the cause,” says computational astrophysicist Starrfield, a professor in the School of Earth and Space Exploration at ASU. “No one suspected novae were violent enough to be emitting at these very high energies. However, it now seems possible that a signification fraction – near 100% – of novae are gamma ray sources.”

Origins unknown
The white dwarf star V407 Cyg lies 9,000 light-years away in the plane of our Milky Way galaxy. It erupted in a rare type of nova called a likely recurrent symbiotic nova, in which the companion star is a pulsating red giant star (about 500 times the size of the sun) blowing out a strong stellar wind. The explosion of the white dwarf occurs inside the atmosphere of the companion star.

Researchers suggested that the gamma rays in the nova were generated when the blast waves from the nova collided with the very dense winds from the red giant, something that doesn’t appear in classical novae.

Although the LAT followed up on later optically bright classical novae, it saw nothing for two years, and the theory that V407 Cyg was a special case seemed confirmed. Then, in June 2012, two separate novae were seen in gamma rays: Nova Sco 2012 and Nova Mon 2012 both emitted detectable levels of gamma rays.

But Nova Sco 2012 and Nova Mon 2012 are classical novae accreting from small, nearby companions. There’s no thick stellar wind to produce a shock like there is in V407 Cyg. So where are the gamma rays coming from?

The answer at the moment is: We don’t know.

Although researchers can’t yet explain how and why, what we do know is that novae can be gamma ray emitters and they are not as rare as originally suspected.

“We are puzzled and ongoing studies of possible causes are underway via computer modeling of the events,” says Starrfield. “This exciting discovery is telling us something important about the explosions of classical novae but we don’t, as yet, know what it means.”

###

Image: This picture is an artist’s conception of the explosion of V407 Cyg. It shows the white dwarf exploding inside the outer layers of its nearby companion star. Photo by: (c) David A. Hardy/astroart.org

(Nikki Cassis)
 

07/30/2014

New research shows that more than four billion years ago, the surface of Earth was heavily reprocessed – or mixed, buried and melted – as a result of giant asteroid impacts. A new terrestrial bombardment model based on existing lunar and terrestrial data sheds light on the role asteroid bombardments played in the geological evolution of the uppermost layers of the Hadean Earth (approximately 4 to 4.5 billion years ago).

An international team of researchers published their findings in the July 31, 2014 issue of Nature.

“When we look at the present day, we have a very high fidelity timeline over the last about 500 million years of what’s happened on Earth, and we have a pretty good understanding that plate tectonics and volcanism and all these kinds of processes have happened more or less the same way over the last couple of billion years,” says Lindy Elkins-Tanton, director of the School of Earth and Space Exploration at Arizona State University.

But, in the very beginning of Earth’s formation, the first 500 million years, there’s a less well-known period which has typically been called the Hadean (meaning hell-like) because it was assumed that it was wildly hot and volcanic and everything was covered with magma – completely unlike the present day.

Terrestrial planet formation models indicate Earth went through a sequence of major growth phases: accretion of planetesimals and planetary embryos over many tens of millions of years; a giant impact that led to the formation of our Moon; and then the late bombardment, when giant asteroids, dwarfing the one that presumably killed the dinosaurs, periodically hit ancient Earth.

While researchers estimate accretion during late bombardment contributed less than one percent of Earth’s present-day mass, giant asteroid impacts still had a profound effect on the geological evolution of early Earth. Prior to four billion years ago Earth was resurfaced over and over by voluminous impact-generated melt. Furthermore, large collisions as late as about four billion years ago, may have repeatedly boiled away existing oceans into steamy atmospheres. Despite heavy bombardment, the findings are compatible with the claim of liquid water on Earth’s surface as early as about 4.3 billion years ago based on geochemical data.

A key part of Earth’s mysterious infancy period that has not been well quantified in the past is the kind of impacts Earth was experiencing at the end of accretion. How big and how frequent were those incoming bombardments and what were their effects on the surface of the Earth? How much did they affect the ability of the now cooling crust to actually form plates and start to subduct and make plate tectonics? What kind of volcanism did it produce that was different from volcanoes today?”

“We are increasingly understanding both the similarities and the differences to present day Earth conditions and plate tectonics,” says Elkins-Tanton. “And this study is a major step in that direction, trying to bridge that time from the last giant accretionary impact that largely completed the Earth and produced the Moon to the point where we have something like today’s plate tectonics and habitable surface.”

The new research reveals that asteroidal collisions not only severely altered the geology of the Hadean Earth, but likely played a major role in the subsequent evolution of life on Earth as well.

“Prior to approximately four billion years ago, no large region of Earth’s surface could have survived untouched by impacts and their effects,” says Simone Marchi, of NASA’s Solar System Exploration Research Virtual Institute at the Southwest Research Institute. “The new picture of the Hadean Earth emerging from this work has important implications for its habitability.”

Large impacts had particularly severe effects on existing ecosystems. Researchers found that on average, Hadean Earth could have been hit by one to four impactors that were more than 600 miles wide and capable of global sterilization, and by three to seven impactors more than 300 miles wide and capable of global ocean vaporization.

"During that time, the lag between major collisions was long enough to allow intervals of more clement conditions, at least on a local scale," said Marchi. "Any life emerging during the Hadean eon likely needed to be resistant to high temperatures, and could have survived such a violent period in Earth’s history by thriving in niches deep underground or in the ocean’s crust.””

Image: An artistic conception of the early Earth, showing a surface pummeled by large impacts, resulting in extrusion of deep seated magma onto the surface. At the same time, distal portion of the surface could have retained liquid water. Image Credit: Simone Marchi.

(Nikki Cassis)

 

07/28/2014

ASU team shows evidence for one mineral affecting the most fundamental process in organic chemistry: carbon-hydrogen bond breaking and making

Reactions among minerals and organic compounds in hydrothermal environments are critical components of the Earth’s deep carbon cycle, they provide energy for the deep biosphere, and may have implications for the origins of life. However, very little is known about how minerals influence organic reactions. A team of researchers from Arizona State University have demonstrated how a common mineral acts as a catalysts for specific hydrothermal organic reactions – negating the need for toxic solvents or expensive reagents.

At the heart of organic chemistry, aka carbon chemistry, is the covalent carbon-hydrogen bond (C–H bond) ─ a fundamental link between carbon and hydrogen atoms found in nearly every organic compound.

The essential ingredients controlling chemical reactions of organic compounds in hydrothermal systems are the organic molecules, hot pressurized water, and minerals, but a mechanistic understanding of how minerals influence hydrothermal organic reactivity has been virtually nonexistent.

The ASU team set out to understand how different minerals affect hydrothermal organic reactions and found that a common sulfide mineral (ZnS, or Sphalerite) cleanly catalyzes a fundamental chemical reaction – the making and breaking of a C-H bond.

Their findings are published in the July 28 issue of the Proceedings of the National Academy of Sciences. The paper was written by a transdisciplinary team of ASU researchers that includes: Jessie Shipp (2013 PhD in Chemistry & Biochemistry), Ian Gould, Lynda Williams, Everett Shock, and Hilairy Hartnett. The work was funded by the National Science Foundation.

“Typically you wouldn’t expect water and an organic hydrocarbon to react. If you place an alkane in water and add some mineral it’s probably just going to sit there and do nothing,” explains first author Shipp. “But at high temperature and pressure, water behaves more like an organic solvent, the thermodynamics of reactions change, and suddenly reactions that are impossible on the bench-top start becoming possible. And it’s all using naturally occurring components at conditions that can be found in past and present hydrothermal systems.”

A mineral in the mix
Previously, the team had found they could react organic molecules in hot pressurized water to produce many different types of products, but reactions were slow and conversions low. This work, however, shows that in the presence of sphalerite, hydrothermal reaction rates increased dramatically, the reaction approached equilibrium, and only one product formed. This very clean, very simple reaction was unexpected.

“We chose sphalerite because we had been working with iron sulfides and realized that we couldn’t isolate the effects of iron from the effects of sulfur. So we tried a mineral with sulfur but not iron. Sphalerite is a common mineral in hydrothermal systems so it was a pretty good choice. We really didn't expect it to behave so differently from the iron sulfides,” says Hartnett, an associate professor in the School of Earth and Space Exploration, and in the Department of Chemistry and Biochemistry at ASU.

This research provides information about exactly how the sphalerite mineral surface affects the breaking and making of the C-H bond. Sphalerite is present in marine hydrothermal systems i.e., black smokers, and has been the focus of recent origins-of-life investigations.

For their experiments, the team needed high pressures (1000 bar - nearly 1000 atm) and high temperatures (300°C) in a chemically inert container. To get these conditions, the reactants (sphalerite, water, and an organic molecule) are welded into a pure gold capsule and placed in a pressure vessel, inside a furnace. When an experiment is done, the gold capsule is frozen in liquid nitrogen to stop the reaction, opened and allowed to thaw while submerged in dichloromethane to extract the organic products.

“This research is a unique collaboration because Dr. Gould is an organic chemist and you combine him with Dr. Hartnett who studies carbon cycles and environmental geochemistry, Dr. Shock who thinks in terms of thermodynamics and about high temperature environments, and Dr. Williams who is the mineral expert, and you get a diverse set of brains thinking about the same problems,” says Shipp.

Hydrothermal organic reactions affect the formation, degradation, and composition of petroleum, and provide energy and carbon sources for microbial communities in deep sedimentary systems. The results have implications for the carbon cycle, astrobiology, prebiotic organic chemistry, and perhaps even more importantly for Green Chemistry (a philosophy that encourages the design of products and processes that minimize the use and generation of hazardous substances).

“This C-H bond activation is a fundamental step that is ultimately necessary to produce more complex molecules – in the environment those molecules could be food for the deep biosphere – or involved in the production of petroleum fuels,” says Hartnett. “The green chemistry side is potentially really cool – since we can conduct reactions in just hot water with a common mineral that ordinarily would require expensive or toxic catalysts or extremely harsh – acidic or oxidizing – conditions.”

Image 1: A team of ASU researchers has demonstrated that a particular mineral, sphalerite, can affect the most fundamental process in organic chemistry: carbon-hydrogen bond breaking and making. This is a sample of gem-quality sphalerite in a quartz matrix. Photo by: Tom Sharp

Image 2: Gold capsule used for the experiment. Photo by: Jessie Shipp

(Nikki Cassis)

 

 

07/17/2014

Asteroids named for two ASU faculty members

Two Arizona State University professors can add an unusual honor to the long list of accolades they have received: An asteroid has been named after each of them. This ‘out-of-this-world’ honor has been conferred on professors Phil Christensen and Dave Williams. The two planetary geologists, both faculty members in ASU’s School of Earth and Space Exploration, now have even more reason to be gazing at the night sky.

You know the names of our solar system’s planets, but you might not have realized that thousands of asteroids and minor planets revolving around the sun also have names.

Asteroid (10461) Dawilliams was discovered on December 6, 1978, by E. Bowell and A. Warnock at Palomar Observatory. It orbits about 2.42 astronomical units from the Earth in the Main Belt, the vast asteroid belt located between the orbits of Mars and Jupiter.

Despite Hollywood’s love of Earth-smashing asteroid blockbusters, Williams has no worries that “his” asteroid will make doomsday headlines.

“It’s very unlikely that it will hit Earth, as it is in a stable orbit in the Main Belt,” explains Williams.
Also honored with an asteroid named for his work is Christensen, the instrument scientist for the OSIRIS-Rex Thermal Emission Spectrometer, a mineral-scouting instrument on the OSIRIS-REx mission to asteroid Bennu. He was also the principal investigator for the infrared spectrometers and imagers on NASA’s Mars Global Surveyor, Mars Odyssey, and Mars Exploration Rovers.

The asteroid is named (90388) Philchristensen and like Williams’ it too is a Main Belt asteroid that is relatively small – approximately 4.6 kilometers (2.8 miles) across. It was discovered November 24, 2003 by the Catalina Sky Survey. It also poses no risk of collision with Earth.

“My research has long focused on Mars,” says Christensen. “But my broader interests involve all solar system bodies, and I’ve spent the last several years working on an asteroid mission. I really appreciate this honor.”

What’s in a name?
Having a namesake in the sky is no small honor. Unlike the selling of star names over the Internet, the naming of asteroids is serious business, presided over by the International Astronomical Union, an organization of professional astronomers.

Upon its discovery, an asteroid is assigned a provisional designation by the Minor Planet Center of the IAU that involves the year of discovery, two letters and, if need be, further digits. When its orbit can be reliably predicted, the asteroid receives a permanent number and becomes eligible for naming. Proposed names must be approved by the IAU’s Committee on Small Body Nomenclature.

Although many objects end up being named after astronomers and other scientists, some discoverers have named the object after celebrities. All four Beatles have their names on asteroids, for example, and there is even one named after James Bond – Asteroid (9007) James Bond.

“I was very surprised to receive this honor from the astronomical community. Only a select few of the Dawn at Vesta participating scientists, who did exemplary work during the mission, were so honored,” said Williams, whose expertise in mapping of volcanic surfaces has been key to developing geologic maps of planetary bodies that include Mars, Io and Vesta.

Christensen and Williams share this honor with several colleagues in the School of Earth and Space Exploration. The following all have namesakes in the sky:

  • Professor Erik Asphaug - Asteroid (7939) Asphaug
  • Professor Jim Bell - Asteroid (8146) Jimbell
  • Foundation Professor and SESE Director Lindy Elkins-Tanton - Asteroid (8252) Elkins-Tanton
  • Professor Emeritus Ronald Greeley - Asteroid (30785) Greeley, and Greeley’s Haven (on Mars)
  • Regents Professor Emeritus Carleton Moore - Asteroid (5046) Carletonmoore
  • Regents’ Professor Sumner Starrfield - Asteroid (19208) Starrfield
  • Professor Meenakshi Wadhwa - Asteroid (8356) Wadhwa

Image credit: NASA/JPL-Caltech

(Nikki Cassis)

07/17/2014

Researchers discover natural clay deposits with antibacterial properties

Superbugs, they're called: Pathogens, or disease-causing microorganisms, resistant to multiple antibiotics.

Such antibiotic resistance is now a major public health concern.

"This serious threat is no longer a prediction for the future," states a 2014 World Health Organization report, "it's happening right now in every region of the world and has the potential to affect anyone, of any age, in any country."

Could the answer to this threat be hidden in clays formed in minerals deep in the Earth?

Biomedicine meets geochemistry

"As antibiotic-resistant bacterial strains emerge and pose increasing health risks," says Lynda Williams, a biogeochemist at Arizona State University (ASU), "new antibacterial agents are urgently needed."

To find answers, Williams and colleague Keith Morrison of ASU set out to identify naturally-occurring antibacterial clays effective at killing antibiotic-resistant bacteria.

The scientists headed to the field--the rock field. In a volcanic deposit near Crater Lake, Oregon, they hit pay dirt.

Back in the lab, the researchers incubated the pathogens Escherichia coli and Staphylococcus epidermidis, which breeds skin infections, with clays from different zones of the Oregon deposit.

They found that the clays' rapid uptake of iron impaired bacterial metabolism. Cells were flooded with excess iron, which overwhelmed iron storage proteins and killed the bacteria.

"The ability of antibacterial clays to buffer pH also appears key to their healing potential and viability as alternatives to conventional antibiotics," state the scientists in a paper recently published in the journal Environmental Geochemistry and Health.

"Minerals have long had a role in non-traditional medicine," says Enriqueta Barrera, a program director in the National Science Foundation's (NSF) Division of Earth Sciences, which funded the research.

"Yet there is often no understanding of the reaction between the minerals and the human body or agents that cause illness. This research explains the mechanism by which clay minerals interfere with the functioning of pathogenic bacteria. The results have the potential to lead to the wide use of clays in the pharmaceutical industry."

Ancient remedies new again

Clay minerals, says Williams, have been sought for medicinal purposes for millennia.

Studies of French clays--green clays historically used in France in mineral baths--show that the clays have antibacterial properties. French green clays have been used to treat Mycobacterium ulcerans, the pathogen that causes Buruli ulcers.

Common in Africa, Buruli ulcers start as painful skin swellings. Then infection leads to the destruction of skin and large, open ulcers on arms or legs.

Delayed treatment--or treatment that doesn't work--may cause irreversible deformities, restriction of joint movement, widespread skin lesions, and sometimes life-threatening secondary infections.

Treatment with daily applications of green clay poultices healed the infections. "These clays," says Williams, "demonstrated a unique ability to kill bacteria while promoting skin cell growth."

Unfortunately, the original French green clays were depleted. Later testing of newer samples didn't show the same results.

Research on French green clays, however, spurred testing of other clays with likely antibacterial properties.

"To date," says Williams, "the most effective antibacterial clays are those from the Oregon deposit."

Samples from an area mined by Oregon Mineral Technologies (OMT) proved active against a broad spectrum of bacteria, including methicillin-resistant S. aureus (MRSA) and extended-spectrum beta-lactamase-resistant E. coli (ESBL).

What's in those rocks?

Understanding the geologic environment that produces antibacterial minerals is important for identifying other promising locations, says Williams, "and for evaluating specific deposits with bactericidal activity."

The OMT deposit was formed near volcanoes active over tens to hundreds of thousands of years. The Crater Lake region is blanketed with ash deposits from such volcanoes.

OMT clays may be 20 to 30 million years old. They were "born" eons before deposits from volcanoes such as Mt. Mazama, which erupted 7,700 years ago to form the Crater Lake caldera.

Volcanic eruptions over the past 70,000 or so years produced silica-rich magmas and hydrothermal waters that may have contributed to the Oregon deposit's antibacterial properties.

To find out, Williams and Morrison took samples from the main OMT open pit. Four types of rocks were collected: two blue clays, and one white and one red "alteration zone" rock from the upper part of the deposit.

Blue clay to the rescue

The OMT blue samples were strongly bactericidal against E. coli and S. epidermidis. The OMT white sample reduced the population of E. coli and S. epidermidis by 56 percent and 29 percent, respectively, but the red sample didn't show an antibacterial effect.

"We can use this information to propose the medicinal application of certain natural clays, especially in wound healing," says Williams.

Chronic, non-healing wounds, adds Morrison, are usually more alkaline (vs. acidic) than healthy skin. The pH of normal skin is slightly acidic, which keeps numbers of bacteria low.

"Antibacterial clays can buffer wounds to a low [more acidic] pH," says Williams, like other accepted chronic wound treatments, such as acidified nitrate. "The clays may shift the wound environment to a pH range that favors healing, while killing invading bacteria."

The Oregon clays could lead to the discovery of new antibacterial mechanisms, she says, "which would benefit the health care industry and people in developing nations. A low-cost topical antibacterial agent is quickly needed."

Answers to Buruli ulcers, MRSA and other antibiotic-resistant infections may lie not in a high-tech lab, but in ancient rocks forged in a hot zone: Oregon's once--and perhaps future--volcanoes.

Image: Are the best medicines hidden in the Earth? French green clays are used for healing Buruli ulcers. Credit: Thierry Brunet de Courssou

(Written by Cheryl Dybas, NSF)

07/15/2014

Follow the adventures of Prof. Youngbull in the Alvin submersible

Our very own intrepid explorer Cody Youngbull is about to go where no one has gone before: 1.5 km below the ocean surface in the Alvin submersible to explore an underwater volcano!

You can follow his journey on SESE’s Explorers Blog at: http://asuexplorers.wordpress.com

Cody just posted his first entry this weekend as he and fellow SESE explorers Amanda and Greg arrived in Portland to begin their scientific cruise.

Stay tuned to the blog for more updates!

 

 

07/15/2014

A heat-sensing camera designed at Arizona State University has provided data to create the most detailed global map yet made of Martian surface properties.

The map uses data from the Thermal Emission Imaging System (THEMIS), a nine-band visual and infrared camera on NASA’s Mars Odyssey orbiter. A version of the map optimized for scientific researchers is available at the U.S. Geological Survey (USGS).

The new Mars map was developed by the Geological Survey's Robin Fergason at the USGS Astrogeology Science Center in Flagstaff, Arizona, in collaboration with researchers at ASU's Mars Space Flight Facility. The work reflects the close ties between space exploration efforts at Arizona universities and the U.S. Geological Survey.

"We used more than 20,000 THEMIS nighttime temperature images to generate the highest resolution surface property map of Mars ever created," says Fergason, who earned her doctorate at ASU in 2006. "Now these data are freely available to researchers and the public alike."

Surface properties tell geologists about the physical nature of a planet or moon's surface. Is a particular area coated with dust, and if so, how thick is it likely to be? Where are the outcrops of bedrock? How loose are the sediments that fill this crater or that valley? A map of surface properties lets scientists begin to answer questions such as these.

Darker means cooler and dustier

The new map uses nighttime temperature images to derive the "thermal inertia" for areas of Mars, each the size of a football field. Thermal inertia is a calculated value that represents how fast a surface heats up and cools off. As day and night alternate on Mars, loose, fine-grain materials such as sand and dust change temperature quickly and thus have low values of thermal inertia. Bedrock represents the other end of the thermal inertia range: because it cools off slowly at night and warms up slowly by day, it has a high thermal inertia.

"Darker areas in the map are cooler at night, have a lower thermal inertia and likely contain fine particles, such as dust, silt or fine sand," Ferguson says. The brighter regions are warmer, she explains, and have surfaces with higher thermal inertia. These consist perhaps of coarser sand, surface crusts, rock fragments, bedrock or combinations of these materials.

The designer and principal investigator for the THEMIS camera is Philip Christensen, Regents' Professor of Geological Sciences in the School of Earth and Space Exploration, part of the College of Liberal Arts and Sciences on the Tempe campus. (Four years ago, Christensen and ASU researchers used daytime THEMIS images to create a global Mars map depicting the planet's landforms, such as craters, volcanoes, outflow channels, landslides, lava flows and other features.)

"A tremendous amount of effort has gone into this great global product, which will serve engineers, scientists and the public for many years to come," Christensen says. "This map provides data not previously available, and it will enable regional and global studies of surface properties. I'm eager to use it to discover new insights into the recent surface history of Mars."

As Fergason notes, the map has an important practical side. "NASA used THEMIS images to find safe landing sites for the Mars Exploration Rovers in 2004, and for Curiosity, the Mars Science Laboratory rover, in 2012," she says. "THEMIS images are now helping NASA select a landing site for its next Mars rover in 2020."

Image: A small impact crater on Mars named Gratteri, 4.3 miles (6.9 km) wide, lies at the center of large dark streaks. Unlike an ordinary daytime photo, this nighttime image shows how warm various surface areas are. Brighter tones mean warmer temperatures, which indicate areas with rockier surface materials. Darker areas indicate cooler and dustier terrain. For example, the bright narrow rings scattered across the image show where rocks are exposed on the uplifted rims of impact craters. Broad, bright areas show expanses of bare rock and durable crust. Fine-grain materials, such as dust and sand, show up as dark areas, most notably in the streaky rays made of fine material flung away in the aftermath of the meteorite's impact. Photo by: NASA/JPL-Caltech/Arizona State University

(Robert Burnham)

07/15/2014

The Marston Exploration Theater at the School of Earth and Space Exploration is currently presenting two science-themed programs: To the Edge of the Universe and The Search: Discovering Unknown Worlds. These shows alternate each Wednesday evening at 7:30 p.m. and each Saturday at 1:00 p.m. and 3:30 p.m.

Between now through August 16th we are offering a ‘Buy Three - Staff is Free’ discount. Bring three guests (family or friends), and receive one staff admission for free. Tickets are $7.50 for general admission and $5.50 for students of any age. This promotion is only available at the door (no online reservations for this offer); the box office is open 45 minutes before show time.

The Marston Exploration Theater is located in ISTB 4 at Terrace Mall and McAllister Ave.

Marston presentations are live-narrated, 3-D immersive experiences designed for all audiences. For presentation descriptions and a calendar of show times visit: http://sese.asu.edu/marston