News and Updates

02/02/2015

ASU SIMS facility shrinks geochemical analysis into the nanometer regime

Two secondary ion mass spectrometry (SIMS) laboratories in the Bateman Physical Science Complex were recognized as hotbeds of scientific research, thanks to the expertise of researchers in Arizona State University’s School of Earth and Space Exploration (SESE) and the Department of Chemistry and Biochemistry (DCB). Professors Richard Hervig, Lynda Williams, and Christy Till of SESE and Professor Peter Williams and postdoctoral researcher Maitrayee Bose of DCB have been awarded $1 million over the next three years to operate their joint laboratories as a national facility for research into the Earth Sciences using this high-sensitivity microbeam analysis technique.

SIMS is an analytical tool permitting measurements of elemental concentration and isotope ratios on extremely tiny areas, so that chemical and isotopic variability on scales from a few micrometers down to several nanometers can be determined.

The spectrometers use beams of ionized atoms to focus on spots as small as 50 nanometers in size, which is less than one-thousandth the width of a human hair. The ions strike the surface and blast off and ionize atoms, which are then separated by mass and measured in sensitive detectors capable of counting individual ions. The process of scanning the beam over the surface creates a high-resolution chemical and/or isotopic image of the sample.

Currently, ASU has one of the most extensive arrays of SIMS instrumentation and SIMS expertise in the world. The ASU researchers have been consistently on the leading edge of innovation in micro-elemental analysis. SIMS research at ASU dates back to 1984 with the acquisition of a Cameca (Paris) ims3f ion microscope by Peter Williams, capable of analysis in few-micrometer areas. A more modern and more powerful ims6f microscope was added in 1999 under the leadership of Hervig. Continuing the tradition of being at the leading edge of the instrumentation, Peter Williams (with Hervig, Lynda Williams and other ASU researchers) spearheaded the acquisition of a Cameca NanoSIMS instrument in 2011, with the capability to analyze areas as small as tens of nanometers.

This combination of instruments enables applications to a broad range of scientific problems, including analyses of a wide variety of natural and synthetic inorganic materials from this planet and others, semiconductors and even biological materials.

“We have been operating as an NSF-funded national facility since early 2007,” says Hervig, professor in ASU’s School of Earth and Space Exploration and director of the ASU SIMS facility. “The 2015 renewal allows us to continue to operate as a facility, and makes the NanoSIMS instrument as well as the existing 6f SIMS lab accessible to students, researchers and faculty.”

On the national stage, this facility is a key player in the mix of instrumentation that is required to conduct state-of-the-art microanalytical geochemistry and petrology.

The SESE researchers are widely known for applying their technique to analyze tiny grains in meteorites thought to pre-date our solar system, small fragments of explosive eruptions, clays and nanopores in oil-shale, and characterization of slow elemental and isotopic diffusion in a variety of earth materials, including volcanic minerals.

“With the ability to analyze elemental concentrations in zoned crystals on the nanometer scale using NanoSIMS, we are now able to reconstruct the life history of a magma up to just a few hours before a volcanic eruption and determine the triggers for explosive volcanic eruptions at volcanoes including Yellowstone,” says Till, an assistant professor in the School of Earth and Space Exploration.

Hervig has developed many SIMS techniques for geochemistry and applied them to natural samples from this and other planets as well as a variety of synthetic materials. Lynda Williams has used this technique on a range of materials at the organic/inorganic interface, specifically on the role of nanopores in understanding more about the properties of oil shales (and the environmental impact of mining them).
ASU also has built a reputation for developing novel analytical applications and instrumentation and for fundamental research aimed at understanding the ion formation process. While a central focus of the SESE researchers is on earth science problems, the lab is open to others, and the team commonly works with materials scientists and electrical engineers on campus and in the ASU Research Park, in addition to microbiologists and chemists.

Geochemists from around the world travel to the NSF-funded National SIMS Facility on ASU’s Tempe campus to use the instruments. Since 2007, from 2 to 12 people (undergraduate and graduate students, post-doctoral researchers, senior research scientists, and faculty) have visited the ASU facility each month. They are usually from the US, but also include visitors from other countries.

One of the anonymous proposal reviewers stated: “We all know that the devil is in the details, and it seems that the scale at which the demons operate gets smaller and smaller with each new advancement in analytical capability. Being able to analyze samples with both the normal and NanoSIMS at the ASU facility will open up new frontiers in our understanding of geological problems, and especially in the ability to examine the timescales of geologic processes.” Another reviewer lauded the facility as “one of the most creative and original SIMS labs in the nation.”

Speaking on behalf of the co-investigators, Hervig said, “We are flattered to be recognized for our scientific leadership and excited at the prospects for unprecedented nanometer-scale geochemical analyses now possible with the incorporation of the new NanoSIMS instrument into the facility. This is high praise for the senior members of the team, but we are particularly pleased that the NSF reviewers agreed with our emphasis on involving younger researchers – Till and Bose – who are pushing the limits of NanoSIMS analysis in the earth and space sciences.”

Image: Images from NanoSIMS showing the location of elements in E. coli treated with natural antibacterial clay. The images represent a cross section through bacteria (The images in B, C and D are close-ups of the yellow box indicated in A. ). The data confirm which elements are critical to the antibacterial process and shows the resolution of trace element mapping by SIMS. Images by Maitrayee Bose and research by Keith Morrison and Lynda Williams in the ASU SIMS Facility.

02/02/2015

As one of this year’s Fulbright Scholars, ASU hydrology professor Enrique Vivoni will have an opportunity to work with some of Mexico’s leading experts in his field to advance his collaborative studies of the shared water resources between the U.S. and Mexico.

The Fulbright award will enable Vivoni to spend nine months starting in August 2015, conducting research at the Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE) in Ensenada, Baja California and the research center of CONACYT (Consejo Nacional de Ciencia y Tecnología).

Vivoni is an associate professor in the School of Earth and Space Exploration and the School of Sustainable Engineering and the Built Environment, one of ASU’s Ira A. Fulton Schools of Engineering.

Each year, the U.S. Fulbright Scholar Program awards about 800 highly sought after teaching and/or research grants to selected U.S. faculty and experienced professionals, enabling them to engage in collaborative studies and research in more than 125 countries. Award recipients are chosen for exemplary achievements and proven leadership in their fields.

Vivoni’s research activities focus on the intersection of hydrology and its allied disciplines – ecology, meteorology and geomorphology – for improving understanding of water resources in this region. He has made significant contributions to the understanding of ecohydrologic processes in semi-arid areas. In recent years, his research has been funded by the National Science Foundation, the United States Department of Agriculture, Department of Defense, NASA, The Nature Conservancy, and the U.S. Geological Survey.

During his time in Ensenada, he will be conducting atmospheric and hydrologic research related to climate change in northern Mexico. Vivoni’s Fulbright project will build upon a decade of investigation in northern Mexico with a range of collaborators from US and Mexican institutions.

“I am most interested in generating cross-border knowledge on water resources that can help both countries confront and adapt to changing land cover and climate conditions,” says Vivoni, of his upcoming trip.

Vivoni's most notable accomplishments include a 2008 U.S. Fulbright Scholar Award, the Presidential Early Career Award for Scientists and Engineers, a Kavli Fellow, and a Leopold Leadership Fellow.

Credit: ASU Magazine

(Nikki Cassis)

 

01/28/2015

Founding Director of the Center for Meteorite Studies, Dr. Carleton B. Moore, has been inducted into the Mineralogical Society of Arizona's Hall of Fame! This award recognizes, among other things, Dr. Moore's many contributions to education and public outreach through presentations to schools and clubs in Arizona (Photo: Dr. Carleton B. Moore hosts the ASU Center for Meteorite Studies booth at the Sedona Gem & Mineral Club Annual Show. Image credit: ASU/CMS).

Dr. Moore was editor of the journal Meteoritics for 20 years. He was a member of the Lunar Sample Preliminary Examination Team for the Apollo program, and a principal investigator for the returned lunar sample program for all the Apollo missions. Dr. Moore’s research efforts have focused on the geochemistry of meteorites, lunar samples and analytical geochemical problems. Additional research interests have taken advantage of the great statistical depth present in the Center for Meteorite Studies collections, including statistical studies of meteorite compositions and homogeneity, the origin of the low calcium achondrites, trace elements in iron meteorites, and high- and low-temperature phases, including organic compounds, in carbonaceous chondrites.

Dr. Moore received his Ph.D. from the California Institute of Technology in 1960, and served as Founding Director of the Center for Meteorite Studies for over 40 years. In 2011, on the occasion of the Center's 50th anniversary, the ASU meteorite collection – the largest university meteorite collection in the world – was officially named the Carleton B. Moore Meteorite Collection

(Center for Meteorite Studies)

 

01/16/2015

More than twenty-four universities and colleges launch the Inspark Science Network to improve outcomes in science courses with traditionally high failure rates

More than 200 faculty members and college presidents will discuss the future of science education and demonstrate groundbreaking technology that will power the Inspark Science Network today at Arizona State University’s Tempe campus.

Established to lead a digital revolution in science education, the Inspark Science Network was launched by Arizona State University (ASU) and Smart Sparrow to develop and share courses that will help students complete general science education courses. The Bill & Melinda Gates Foundation has awarded a $4.5 million grant to Smart Sparrow for the new initiative. Success in general science education courses has been a barrier to college completion, particularly for low-income and first-generation students.

“Having more students successfully complete college science courses is a huge benefit to our society and will strengthen our nation’s competitiveness,” said ASU President Michael Crow. “Efforts like these, which utilize technology to engage students in a more meaningful way and encourage them to learn science through the exploration of the worlds around them, will be vital in removing traditional barriers to a college degree.”

Australian technology firm Smart Sparrow, a pioneer in adaptive learning authoring platforms, will provide tools that enable faculty to create and share digital courses, with an emphasis on allowing individual educators to exert pedagogical control and track student progress using sophisticated analytics.

As part of the launch of Inspark, over 200 college and university presidents and faculty members are gathering today to demo the new technology powering the network. The day will include a panel discussion featuring President Crow, Nobel Laureate Lee Hartwell, Maricopa Community Colleges Executive Vice Chancellor and Provost Maria Harper-Marinick, and Director of the ASU Origins Project Lawrence Krauss.

“The Inspark Science Network will empower teachers to create learning experiences that combine the power of adaptive learning with the magic of great classroom instruction,” said Dr. Dror Ben-Naim, CEO and Founder of Smart Sparrow. “We are proud to establish a world-leading team of experts, and contribute toward creating tools that will have a lasting and significant impact on student success.”

The Inspark Science Network is an initiative of Smart Sparrow, in partnership with ASU’s newly established Center for Education Through Exploration (ETX). ETX, directed by Ariel Anbar, a President’s Professor in the School of Earth & Space Exploration and the Department of Chemistry and Biochemistry at ASU, is an initiative designed to promote active learning, teaching science as the means by which we explore the unknown, rather than simply learning what is already known. Founding Inspark partners also include Achieving the Dream, The University of Texas at Arlington, and e*mersion, a science animation company.

With help from Achieving the Dream, a national organization focused on improving outcomes for low-income and traditionally underserved students, Inspark will produce innovative courseware and work to ensure that faculty and community colleges around the country can access the network. George Siemens, Executive Director of The University of Texas at Arlington’s Learning Innovation and Networked Knowledge Lab, will lead a research effort to test the efficacy of the new courses and networks.
Professor Anbar will guide the Inspark Science Network in developing “smart courses” that teach basic science concepts through the exploration of intriguing questions, placing traditional science content in a compelling context.

“We believe science is fundamental to teaching students how to be critical thinkers and successful contributors to the future of our society,” Anbar said. “This network will pull together like-minded professionals who are passionate about teaching and committed to ensuring that all students succeed.”

Representatives from community colleges across Arizona will be participating in the special events today at ASU. Among the initial twenty four teaching partners are universities and community colleges such as American Public University System, Houston Community College, Lorain County Community College, and Miami Dade College.

For more information or to register in the Inspark Science Network please visit http://inspark.education/.

 

01/13/2015

Arizona State University hydrologist Enrique Vivoni has been awarded a Leopold Leadership Fellowship –– a prestigious North American program focused on communicating scientific research to a wide audience. Vivoni, an associate professor in ASU’s School of Earth and Space Exploration and the School of Sustainable Engineering and the Built Environment, is one of 20 Leopold Leadership fellows for 2015.

Water in the southwestern U.S. and northern Mexico is a contentious issue that traverses disciplinary boundaries. Vivoni’s research activities focus on the intersection of hydrology and its allied disciplines (ecology, meteorology and geomorphology) for improving our understanding of water resources in this region. A hallmark of his research achievements has been the collaborative studies on the shared water resources between the U.S. and Mexico.

“I am honored to be chosen as a Leopold Fellow and I look forward to serving as a focal point for water resources issues in the southwestern U.S. and northern Mexico,” Vivoni said. “The leadership skills developed through the Leopold Leadership program will be useful for addressing societal needs related to water resources sustainability.”

Vivoni is internationally recognized in the fields of distributed hydrologic modeling, ecohydrology of semi-arid regions, North American monsoon studies and integration of engineering tools for advancing hydrologic science.

The Leopold Leadership Program, based at Stanford University’s Woods Institute for the Environment, is a competitive fellowship for outstanding academic environmental scientists who are actively engaged in outreach to decision-makers and the public about their work. Each year, the program selects up to 20 midcareer academic environmental scientists as fellows.

The fellows were chosen for their outstanding scientific qualifications, demonstrated leadership ability, and strong interest in sharing their knowledge beyond traditional academic audiences. The fellows will receive two weeks of intensive communication and leadership training in how to deliver information about their research to journalists, policymakers, business leaders, and the public.

The Leopold Leadership Program was founded in 1998 to fill a critical gap in environmental decision-making: getting the best scientific knowledge into the hands of government, nonprofit, and business leaders and the public to further the development of sustainable policies and practices.

The list of 2015 Fellows is below, and more information about the program is available at http://leopoldleadership.stanford.edu.

Image: Arizona State University professor Enrique Vivoni has been named a Leopold Leadership fellow for 2015.
Credit: ASU Magazine
 

(Nikki Cassis)

 

01/12/2015

Alberto Behar, a research professor at Arizona State University, who has been operating, designing, building, testing and deploying scientific instruments and robotics in extreme environments for more than 20 years, died Jan. 9, when the plane he was flying crashed north of Los Angeles. He was 47.

Alberto possessed an inquisitive mind. He was passionate. He was driven. He was an explorer. He was widely known for his energy, enthusiasm, and technical excellence. He brought optimism and an accompanying smile to every room he entered.

“Alberto Behar was a uniquely talented engineer, developing ways to measure changes in our natural world in the most challenging environments – the ocean depths or the Antarctic ice cap,” said Lindy Elkins-Tanton, director of the School of Earth and Space Exploration at ASU. “With those around him, he shared both a brilliant mind and a big heart: his students were full partners in a grand adventure. His colleagues quickly came to know his caring nature and irrepressible good humor. We will all miss him tremendously.”

Today much scientific exploration in extreme environments on Earth and in space is done using mobile robots. Alberto dedicated his career to better understanding Earth and beyond by developing instruments that allowed for exploration of regions too dangerous or inaccessible for human explorers.

Alberto had once said that new innovations are a way of overcoming the limits on our ability to explore: “Technology is how we get our senses to a remote location where we can’t actually go ourselves.”

During the course of his career, Alberto has developed instruments and robotics that have reached deep in the ocean’s hydrothermal vents, next to volcanoes, under thick ice sheets, in to the stratosphere and on to other planetary bodies. He participated in the exploration of Mars, serving as the Investigation Scientist for both the Dynamic Albedo of Neutrons (DAN) instrument on the Curiosity rover and the High Energy Neutron Detector on the Mars Odyssey orbiter.

A Greenland research paper, of which Behar was an author, was released today by the Proceedings of the National Academy of Science. The lead author Laurence Smith of UCLA contacted PNAS and asked to have the research dedicated to the memory of Behar. The Acknowledgments section will now begin with: "This research is dedicated to the memory of Dr. Alberto Behar, who tragically passed away January 9, 2015."

The life of an explorer

Alberto’s parents emigrated from Cuba to the United States. Alberto was born and raised in Miami, Fla. and attended the University of Florida, majoring in computer and information engineering sciences. He went on to earn two graduate degrees: a Master of Engineering in Electrical, Computer and Systems Engineering from Rensselaer Polytechnic Institute and a Master of Science in Computer Science with a specialization in robotics from University of Southern California. In 1998, he obtained his doctorate in electrical engineering (astronautics minor) at the University of Southern California in Los Angeles.

Before coming to ASU in 2009, Alberto spent 18 years at NASA’s Jet Propulsion Lab (JPL) operating, designing, building, testing and deploying scientific instruments and robotics in extreme environments.

“From his submarines that peeked under Antarctica to his boats that raced Greenland's rivers, Alberto's work enabled measurements of things we'd never known,” said Thomas Wagner, the Cryosphere Program Scientist at NASA Headquarters. “His creativity knew few bounds.”

Training the next generation of explorers

Alberto was one of the first of a new breed of faculty to join the School of Earth and Space Exploration, according to Kip Hodges, founding director of the school. He was a researcher and educator who actively bridged the gap between science and engineering.

“From the moment he began working toward becoming part of our community, Alberto showed a natural affinity for working with undergraduates through project-based learning and he became a tremendous mentor,” Hodges said. “To him, engineering was an enabling strategy for scientific research, and his enthusiasm for the field was extremely inspirational for many ASU students, not just those with majors in our school.”

Jim Crowell, a researcher in Alberto’s Extreme Environments Robotics and Instrumentation Laboratory, was hired by Alberto following his May 2012 graduation.

“I first started working for Alberto as a student. My last semester, I did a research project with him; the project was a system to analyze the depth of some glacial rivers in Greenland,” says Crowell. “Alberto was my boss, mentor, teacher, and friend. More than anything, he was an incredible mentor and a great friend. He inspired me every day, and he’s the only reason I stayed in Phoenix after I graduated. He always wanted the best for me and my career.”

Alberto’s colleague Jack Farmer, a professor in ASU’s School of Earth and Space Exploration, describes him as “an engineer par excellence” with an amazingly diverse experience designing and testing robotic platforms for the exploration of extreme environments on Earth and ultimately, other planets.

“He brought this amazing experience, along with his infectious enthusiasm for exploration, to the classroom and SESE students were clear beneficiaries,” said Farmer. He and Alberto served together on the MSL team, and shared many experiences during the first 90 days of the mission, as they lived and worked on Mars time.

A passion for life

Alberto was deeply passionate about exploration and discovery and he was highly successful in his career, but he never lost sight of his true love: his family.

“When he wasn’t talking about work, he was talking about his wife and children. He absolutely adored them,” says Crowell. “He told me to focus on my life and having a family. As much fun or important as a career seems, he understood that family and living life was much more important than anything else.”

He is survived by his wife Mary and three children: his son Indra and daughters Isis and Athena.

Friends, colleagues and students agree that Behar was a man of science, with a passion for sharing knowledge and exploring the unknown.

Lance Strumpf, chief pilot at Briles Wing & Helicopter, Inc., became friends with Alberto through aviation. Alberto held dual airline transport pilot and instructor ratings in helicopters and airplanes, as well as Scientific and Rescue SCUBA Diver Certificates and an Emergency Medical Technician Certificate.

“Alberto worked his way onto my staff as a helicopter pilot,” says Strumpf. “He was always welcome in our home. We all loved Alberto. He spent evenings at my house, dinners and at times slept over. He was part of the family. My family spent a week with his family in Scottsdale for Thanksgiving a couple years ago. He toured us through his lab at Arizona State University and gave is a private tour at JPL during the construction of the Mars Curiosity. He loved to share his knowledge.”

“I once asked him what the purpose of one of our projects was,” recalls Crowell, “and he said simply: ‘Because we don’t know.’ He was truly the embodiment of exploration.”

Image:  Alberto stands in front of his "drone-boat", which safely collected measurements of water depth and spectral reflectance needed to calibrate a satellite-based algorithm to map meltwater depths on the ice sheet. Courtesy of Larry Smith
 

01/08/2015

The “Pillars of Creation”, imaged by ASU astronomers 20 years ago, gets makeover

In 1995, NASA’s Hubble Space Telescope released an iconic image that changed people’s perception of space. Appearing in movies, TV shows, and on items from t-shirts to a postage stamp, the photo of the so-called “Pillars of Creation,” offered a glimpse at what the origins of our own solar system’s sun might have looked like.

The awe-inspiring photo revealed never-before-seen details of three staggering columns of cold gas bathed in the scorching ultraviolet light from a cluster of young, massive stars in a small region of the Eagle Nebula, or M16.

Paul Scowen, associate research professor in the School of Earth and Space Exploration at ASU, and former ASU astronomer Jeff Hester conducted the original observation of the nebula.

In celebration of its upcoming 25th anniversary in April, Hubble has revisited the famous pillars, photographing them in both visible and near-infrared light, creating an image far more detailed than the previous one. The high-definition version of the iconic image was possible thanks to upgrades made to the Hubble Space Telescope over the past 25 years.

“It allows us to demonstrate how far Hubble has come in 25 years of observation,” Scowen said during a news conference at the 225th meeting of the American Astronomical Society.

Along with releasing the sharper new photo, the Hubble team revealed an image of the Eagle Nebula in the infrared wavelength, which cuts through the dust and gas, transforming the pillars into eerie, wispy silhouettes seen against a background of myriad stars.


Pillars of destruction

The new image of the pillars illuminates the constantly shifting face of the universe. In addition to showcasing a region giving birth to new stars, the pillars are also being destroyed by the very star light they are bathed in.

“I’m impressed by how transitory these structures are,” said Scowen. “They are actively being ablated away before our very eyes. The ghostly bluish haze around the dense edges of the pillars is material getting heated up and evaporating away into space. We have caught these pillars at a very unique and short-lived moment in their evolution.”

The infrared image reveals that the pillars still exist after two decades but also show changes that have taken place in the nebula over the past two decades.

“These pillars represent a very dynamic, active process,” Scowen said. “The gas is not being passively heated up and gently wafting away into space. The gaseous pillars are actually getting ionized, a process by which electrons are stripped off of atoms, and heated up by radiation from the massive stars. And then they are being eroded by the stars’ strong winds and barrage of charged particles, which are literally sandblasting away the tops of these pillars.”

Our Sun probably formed in a similar turbulent star-forming region. There is evidence that the forming solar system was seasoned with radioactive shrapnel from a nearby supernova. That means that our Sun was formed as part of a cluster that included stars massive enough to produce powerful ionizing radiation, such as is seen in the Eagle Nebula.

“That's the only way the nebula from which the Sun was born could have been exposed to a supernova that quickly, in the short period of time that represents, because supernovae only come from massive stars, and those stars only live a few tens of millions of years,” Scowen explained. "What that means is when you look at the environment of the Eagle Nebula or other star-forming regions, you're looking at exactly the kind of nascent environment that our Sun formed in.”

Image: Astronomers using NASA's Hubble Space Telescope have assembled a bigger and sharper photograph of the iconic Eagle Nebula’s.
Credit: NASA/ESA/Hubble Heritage Team (STScI/AURA)

 

12/08/2014

A recent article published in Science features the Martian meteorite NWA 7034 (aka Black Beauty), and details its discovery and distribution among collections.

CMS holds a 20-gram cut of Black Beauty, which is a polymict breccia containing a diverse assemblage of igneous and “sedimentary” materials. It was most likely produced by impact, but also involved volcanic and low-temperature alteration processes. The bulk chemical composition of this meteorite closely matches that of the Martian crust as measured by NASA’s Mars Exploration Rovers and Mars Odyssey Orbiter. It also contains the most amount of water (approximately ~0.6 wt%) of any of the known Martian meteorites.

See the CT image movie of the Center's slice of this unique and rare meteorite here.

Photo: NWA 7533, aka Black Beauty (Photo credit: NASA).

12/08/2014

Experiments with the high pressure wind tunnel at Arizona State University's Planetary Aeolian Laboratory provide key data for understanding dunes on Saturn's moon Titan.

Saturn's largest moon, Titan, is one of the few solar system bodies — and the only planetary moon — known to have fields of wind-blown dunes on its surface. (The others are Venus, Earth, and Mars.)

New research, using experimental results from the high-pressure wind tunnel at Arizona State University's Planetary Aeolian Laboratory, has found that previous estimates of how fast winds need to blow to move sand-size particles around on Titan are about 40 percent too low.

A team of scientists led by Devon Burr of the University of Tennessee, Knoxville reported the findings Dec. 8 in a paper published in the journal Nature. James K. Smith, engineer and manager of ASU's Planetary Aeolian Laboratory, is one of the paper's co-authors.

Saturn and Titan orbit about ten times farther from the Sun than Earth. Scientists got their first detailed information about Titan when the Cassini/Huygens orbiter and lander arrived in 2004. The short-lived Huygens lander took photos when it reached the surface and as it was descending through Titan's dense, smoggy atmosphere, which has 1.4 times greater pressure than Earth's. These images, plus studies using instruments on the Cassini orbiter, revealed that Titan's geological features include mountains, craters, river channels, lakes of ethane, methane, and propane — and dunes.

Dunes begin to form when the wind picks up loose particles from the ground and drives them to hop, or saltate, downwind. A key part of understanding dunes is to identify the threshold wind speed that causes dune particles to start to move. Geologists have found threshold speeds for sand and dust under various conditions on Earth, Mars, and Venus. But for Titan, with its bizarre conditions, this remained unknown.

Particles of 'sand' as light as freeze-dried coffee

On Titan, where the surface temperature is –290° Fahrenheit, even "sand" is probably unlike sand on Earth, Mars, or Venus. From the Cassini observations and other data, scientists think it is composed of small particles of solid hydrocarbons (or ice wrapped in hydrocarbons), with a density about one-third that of terrestrial sand. In addition, Titan's gravity is low, roughly one-seventh that on Earth. Combined with the particles' low density, this gives them a weight of only about four percent that of terrestrial sand, or roughly as light as freeze-dried coffee grains.

The scientists led by Burr began their study with carefully designed wind tunnel experiments. "We refurbished the high-pressure wind tunnel previously used to study conditions on Venus," Smith explains. To recreate in the tunnel on Earth the wind conditions on Titan, the scientists had to increase the air pressure in the wind tunnel to about 12 times the surface pressure of Earth. And they compensated for the low density of Titan "sand" and the moon's reduced gravity through numerical modeling.

In the end, the Burr team explains, "this simulation reproduces the fundamental physics governing particle motion thresholds on Titan." They add that previous studies, which had extrapolated from wind tunnel experiments designed to mimic conditions on Earth and Mars, produced results that were questionable under Titan's conditions.

The outcome of the wind tunnel experiments show that the previous calculations for wind speeds necessary to lift particles were about 40 to 50 percent too slow. The new experiments show that near the surface of Titan, the most easily moved sand-size particles need winds of at least 3.2 miles per hour (1.4 meters per second) to start moving.

That doesn't sound like much, says Nathan Bridges of the Johns Hopkins University Applied Physics Laboratory, one of the co-authors. "But it makes more sense when you realize this is a dense atmosphere blowing against particles that are very light."

A higher threshold wind speed for making particles move creates an either/or situation in which weak, everyday winds do little or nothing to surface particles, but occasional strong ones readily blow them around and reshape the dunes. The pattern of dunes on Titan shows that despite prevailing winds blowing from the east, the dunes appear shaped by winds from the west, which occur more rarely. Thus the new work indicates that Titan's dunes are seldom stirred into motion — only whenever conditions produce strong westerly winds.

For simplicity, the wind-tunnel modeling ignored some factors, among them whether Titan dune particles are sticky. If they are, the paper's scientists note, then it will take yet-stronger winds to get the particles moving, and the contrasts will be even greater between the normal east wind pattern and the stronger west winds that shape the dunes.

Bridges says, "Titan is a strange place indeed."

The facility that has grown to become ASU's Planetary Aeolian Laboratory was founded in the mid-1970s by the late Ronald Greeley of ASU. The laboratory, located at NASA's Ames Research Center in Mountain View, Calif., has been used for many studies of how wind interacts with particles of sand, dust, and rock. Scientists have also used it to investigate what blowing sand and dust do to Mars spacecraft, such as NASA's Opportunity and Curiosity rovers. ASU operates the laboratory through an agreement with NASA.

The School of Earth and Space Exploration is an academic unit of ASU's College of Liberal Arts and Sciences.

12/04/2014

Arizona State University professor Lawrence Krauss has been named the 2015 Humanist of the Year by the American Humanists Association.

The Humanist of the Year award was established in 1953 to recognize a person of national or international reputation who, through the application of humanist values, has made a significant contribution to the improvement of the human condition.

Previous honorees include astronomer Carl Sagan; Nobel laureates Steven Weinberg, Murray Gell-Mann, Andrei Sakharov and Linus Pauling; polio vaccine discoverer Jonas Salk; feminist Gloria Steinem; biologists Edward O. Wilson and Stephen Jay Gould; psychologist B.F. Skinner; designer Buckminster Fuller; birth control activist Margaret Sanger; and author Kurt Vonnegut.

“I was shocked when I received the news, and humbled when I read the list of previous awardees, many of whom are intellectual heroes of mine,” said Krauss. “To be listed along with that group in any context is an honor of the highest order.

“As it is, I feel privileged that my activities, which ASU has helped foster and which I am motivated to do both because I enjoy them and because I hope that they might have a positive impact, have now also been so generously recognized by this award,” he added.

Krauss is internationally known for his work in theoretical physics and cosmology, and is a well-known author, science communicator, activist and public intellectual. His research covers science from the beginning of the universe to the end of the universe, and includes the interface between elementary particle physics and cosmology, the nature of dark matter, general relativity and neutrino astrophysics.

In addition to being an ASU Foundation Professor, Krauss is the director of the Origins Project at ASU, which explores key questions about our origins, who we are and where we came from, and then holds open forums to encourage public participation.

Krauss is the only physicist to receive major awards from all three U.S. physics societies: the American Physical Society, the American Institute of Physics and the American Association of Physics Teachers.

In 2012 he was given the Public Service Award from the National Science Board for his efforts in communicating science to general audiences. Last year he was awarded the “Roma Award Urbs Universalis 2013” by the Mayor of Rome.

Krauss has authored more than 300 scientific publications and nine books, including his most recent best-seller, "A Universe from Nothing," which offers provocative, revelatory answers to the most basic philosophical questions of existence. It was on the New York Times best-seller list for nonfiction within a week of its release.

Krauss also wrote the international best-seller "The Physics of Star Trek," an entertaining and eye-opening tour of the Star Trek universe, and "Beyond Star Trek," which addressed recent exciting discoveries in physics and astronomy, and takes a look at how the laws of physics relate to notions from popular culture. A book on physicist Richard Feynman, "Quantum Man," was awarded the 2011 Book of the Year by Physics World magazine in the UK.

He has been a frequent commentator and columnist for newspapers such as the New York Times and the Wall Street Journal. He has written regular columns for New Scientist and Scientific American, and appears routinely on radio and television. He was featured with Richard Dawkins in a full-length film documentary, "The Unbelievers," which has been billed as a “rock-n-roll tour film about science and reason.”

Krauss also serves as a co-chair of the board of sponsors of the Bulletin of the Atomic Scientists, on the board of directors of the Federation of American Scientists and is one of the founders of ScienceDebate2012.

Krauss will receive a bronze plate bearing an inscription during the American Humanists Association Annual Conference, May 7-10, 2015, in Denver.

The School of Earth and Space Exploration is an academic unit of ASU's College of Liberal Arts and Sciences.

(Skip Derra)