March 27, 2017 | Atlanta, GA

Experiments led by researchers at the Georgia Institute of Technology suggest the particles that cover the surface of Saturn’s largest moon, Titan, are “electrically charged.” When the wind blows hard enough (approximately 15 mph), Titan’s non-silicate granules get kicked up and start to hop in a motion referred to as saltation. As they collide, they become frictionally charged, like a balloon rubbing against your hair, and clump together in a way not observed for sand dune grains on Earth — they become resistant to further motion. They maintain that charge for days or months at a time and attach to other hydrocarbon substances, much like packing peanuts used in shipping boxes here on Earth.

The findings have just been published in the journal Nature Geoscience.

“If you grabbed piles of grains and built a sand castle on Titan, it would perhaps stay together for weeks due to their electrostatic properties,” said Josef Dufek, the Georgia Tech professor who co-led the study. “Any spacecraft that lands in regions of granular material on Titan is going to have a tough time staying clean. Think of putting a cat in a box of packing peanuts.”

The electrification findings may help explain an odd phenomenon. Prevailing winds on Titan blow from east to west across the moon’s surface, but sandy dunes nearly 300 feet tall seem to form in the opposite direction.

“These electrostatic forces increase frictional thresholds,” said Josh Méndez Harper, a Georgia Tech geophysics and electrical engineering doctoral student who is the paper’s lead author. “This makes the grains so sticky and cohesive that only heavy winds can move them. The prevailing winds aren’t strong enough to shape the dunes.”

To test particle flow under Titan-like conditions, the researchers built a small experiment in a modified pressure vessel in their Georgia Tech lab. They inserted grains of naphthalene and biphenyl — two toxic, carbon and hydrogen bearing compounds believed to exist on Titan’s surface — into a small cylinder. Then they rotated the tube for 20 minutes in a dry, pure nitrogen environment (Titan’s atmosphere is composed of 98 percent nitrogen). Afterwards, they measured the electric properties of each grain as it tumbled out of the tube.

“All of the particles charged well, and about 2 to 5 percent didn’t come out of the tumbler,” said Méndez Harper. “They clung to the inside and stuck together. When we did the same experiment with sand and volcanic ash using Earth-like conditions, all of it came out. Nothing stuck.”

Earth sand does pick up electrical charge when it’s moved, but the charges are smaller and dissipate quickly. That’s one reason why you need water to keep sand together when building a sand castle. Not so with Titan.

“These non-silicate, granular materials can hold their electrostatic charges for days, weeks or months at a time under low-gravity conditions,” said George McDonald, a graduate student in the School of Earth and Atmospheric Sciences who also co-authored the paper.

Visually, Titan is the object in the solar system most like Earth. Data gathered from multiple flybys by Cassini since 2005 have revealed large liquid lakes at the poles, as well as mountains, rivers and potentially volcanoes. However, instead of water-filled oceans and seas, they’re composed of methane and ethane and are replenished by precipitation from hydrocarbon-filled clouds. Titan’s surface pressure is a bit higher than our planet — standing on the moon would feel similar to standing 15 feet underwater here on Earth.

“Titan’s extreme physical environment requires scientists to think differently about what we’ve learned of Earth’s granular dynamics,” said Dufek. “Landforms are influenced by forces that aren’t intuitive to us because those forces aren’t so important on Earth. Titan is a strange, electrostatically sticky world.”

Researchers from the Jet Propulsion Lab, University of Tennessee-Knoxville and Cornell University also co-authored the paper, which is titled “Electrification of Sand on Titan and its Influence on Sediment Transport.”

The study is partially supported by the National Science Foundation (EAR-1150794). Méndez Harper held a National Science Foundation graduate fellowship while conducting the study. McDonald has a National Defense Science and Engineering Graduate Fellowship. Any opinions, findings and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the sponsors.

April 17, 2017 | Atlanta, GA

Massive landslides, similar to those found on Earth, are occurring on the asteroid Ceres. That’s according to a new study led by the Georgia Institute of Technology, adding to the growing evidence that Ceres retains a significant amount of water ice.

The study is published in the journal Nature Geoscience. It used data from NASA’s Dawn spacecraft to identify three different types of landslides, or flow features, on the Texas-sized asteroid.

Type I are relatively round, large and have thick "toes" at their ends. They look similar to rock glaciers and icy landslides in Earth’s arctic. Type I landslides are mostly found at high latitudes, which is also where the most ice is thought to reside near Ceres' surface.

Type II features are the most common of Ceres’ landslides and look similar to deposits left by avalanches on Earth. They are thinner and longer than Type I and found at mid-latitudes. The authors affectionately call one such Type II landslide "Bart" because of its resemblance to the elongated head of Bart Simpson from TV's "The Simpsons."

Ceres' Type III features appear to form when some of the ice is melted during impact events. These landslides at low latitudes are always found coming from large-impact craters.

Georgia Tech Assistant Professor and Dawn Science Team Associate Britney Schmidt led the study. She believes it provides more proof that the asteroid’s shallow subsurface is a mixture of rock and ice.

“Landslides cover more area in the poles than at the equator, but most surface processes generally don’t care about latitude,” said Schmidt, a faculty member in the School of Earth and Atmospheric Sciences. “That’s one reason why we think it’s ice affecting the flow processes. There’s no other good way to explain why the poles have huge, thick landslides; mid-latitudes have a mixture of sheeted and thick landslides; and low latitudes have just a few.”  

The study’s researchers were surprised at just how many landslides Ceres has in general. About 20 percent to 30 percent of craters greater than 6 miles (10 kilometers) wide have some type of landslide associated with them. Such widespread features formed by "ground ice" processes, made possible because of a mixture of rock and ice, have only been observed before on Earth and Mars.

Based on the shape and distribution of landslides on Ceres, the authors estimate that the upper layers of Ceres may range from 10 percent to 50 percent ice by volume.

“These landslides offer us the opportunity to understand what’s happening in the upper few kilometers of Ceres,” said Georgia Tech Ph.D. student Heather Chilton, a co-author on the paper. “That’s a sweet spot between information about the upper meter or so provided by the GRaND (Gamma Ray and Neutron Detector (GRaND) and VIR (Visible and Infrared Spectrometer) instrument data, and the tens of kilometers-deep structure elucidated by crater studies.”

"It’s just kind of fun that we see features on this small planet that remind us of those on the big planets, like Earth and Mars,” Schmidt said. “It seems more and more that Ceres is our innermost icy world.”

The Dawn mission is managed by NASA’s Jet Propulsion Laboratory for NASA's Science Mission Directorate in Washington, D.C. Dawn is a project of the directorate's Discovery Program, managed by NASA's Marshall Space Flight Center in Huntsville, Alabama. UCLA is responsible for overall Dawn mission science. Orbital ATK Inc., in Dulles, Virginia, designed and built the spacecraft. The German Aerospace Center, Max Planck Institute for Solar System Research, Italian Space Agency and Italian National Astrophysical Institute are international partners on the mission team. For a complete list of mission participants, visit: http://dawn.jpl.nasa.gov/mission.

Co-written by Elizabeth Landau, Jet Propulsion Lab

April 17, 2017 | Atlanta, GA

The article 'Behind the Iron Curtain: How Methane-Making Microbes Kept the Early Earth Warm' exposes research on methane interaction over earth's temperature. 

To read the article visit http://www.rh.gatech.edu/news/590491/behind-iron-curtain-how-methane-making-microbes-kept-early-earth-warm

Biography:
 
Jennifer Glass

Dr. Jennifer Glass joined the GT faculty in fall 2013 as Assistant Professor in Earth and Atmospheric Sciences with a courtesy appointment in Biology. She earned BSc degrees in Earth Sciences and Oceanography from the University of Washington, a Ph.D. in Geological Sciences from Arizona State University, and was awarded a NASA Astrobiology Postdoctoral Fellowship at Caltech. Her research focuses on the geochemistry and microbiology of methane and nitrogen in context of the global biochemical cycles and their significance in diverse ecosystems.

Since arrival at GT, she was awarded $849,858 in NASA and NSF funding as PI and $1,808,339 as co-PI, published or submitted seven manuscripts to peer-reviewed journals, and became an Associate Editor for Frontiers in Microbiology. She also gave 15 invited presentations on GT research, and led the creation of the new annual Southeastern Biogeochemistry Symposium, now in its third year.

April 24, 2017 | Atlanta, GA

From the article:  Landslides on Ceres Reflect Hidden Ice

Massive landslides, similar to those found on Earth, are occurring on the asteroid Ceres. That’s according to a new study led by the Georgia Institute of Technology, adding to the growing evidence that Ceres retains a significant amount of water ice.

The study is published in the journal Nature Geoscience. It used data from NASA’s Dawn spacecraft to identify three different types of landslides, or flow features, on the Texas-sized asteroid.

Type I are relatively round, large and have thick "toes" at their ends. They look similar to rock glaciers and icy landslides in Earth’s arctic. Type I landslides are mostly found at high latitudes, which is also where the most ice is thought to reside near Ceres' surface.

Type II features are the most common of Ceres’ landslides and look similar to deposits left by avalanches on Earth. They are thinner and longer than Type I and found at mid-latitudes. The authors affectionately call one such Type II landslide "Bart" because of its resemblance to the elongated head of Bart Simpson from TV's "The Simpsons."

Ceres' Type III features appear to form when some of the ice is melted during impact events. These landslides at low latitudes are always found coming from large-impact craters.

Georgia Tech Assistant Professor and Dawn Science Team Associate Britney Schmidt led the study. She believes it provides more proof that the asteroid’s shallow subsurface is a mixture of rock and ice.

“Landslides cover more area in the poles than at the equator, but most surface processes generally don’t care about latitude,” said Schmidt, a faculty member in the School of Earth and Atmospheric Sciences. “That’s one reason why we think it’s ice affecting the flow processes. There’s no other good way to explain why the poles have huge, thick landslides; mid-latitudes have a mixture of sheeted and thick landslides; and low latitudes have just a few.”  

The study’s researchers were surprised at just how many landslides Ceres has in general. About 20 percent to 30 percent of craters greater than 6 miles (10 kilometers) wide have some type of landslide associated with them. Such widespread features formed by "ground ice" processes, made possible because of a mixture of rock and ice, have only been observed before on Earth and Mars.

Based on the shape and distribution of landslides on Ceres, the authors estimate that the upper layers of Ceres may range from 10 percent to 50 percent ice by volume.

“These landslides offer us the opportunity to understand what’s happening in the upper few kilometers of Ceres,” said Georgia Tech Ph.D. student Heather Chilton, a co-author on the paper. “That’s a sweet spot between information about the upper meter or so provided by the GRaND (Gamma Ray and Neutron Detector (GRaND) and VIR (Visible and Infrared Spectrometer) instrument data, and the tens of kilometers-deep structure elucidated by crater studies.”

"It’s just kind of fun that we see features on this small planet that remind us of those on the big planets, like Earth and Mars,” Schmidt said. “It seems more and more that Ceres is our innermost icy world.”

The Dawn mission is managed by NASA’s Jet Propulsion Laboratory for NASA's Science Mission Directorate in Washington, D.C. Dawn is a project of the directorate's Discovery Program, managed by NASA's Marshall Space Flight Center in Huntsville, Alabama. UCLA is responsible for overall Dawn mission science. Orbital ATK Inc., in Dulles, Virginia, designed and built the spacecraft. The German Aerospace Center, Max Planck Institute for Solar System Research, Italian Space Agency and Italian National Astrophysical Institute are international partners on the mission team. For a complete list of mission participants, visit: http://dawn.jpl.nasa.gov/mission.

Co-written by Elizabeth Landau, Jet Propulsion Lab

For More Information:

Universe Today Article

Space.com Article

Biography:

Britney Schmidt

Dr. Britney Schmidt, Assistant Professor, received a BS in Physics from University of Arizona and Ph.D. in Geophysics and Space physics from UCLA. Her area of expertise is planetary ices and the early solar system. She is keenly interested in the habitability of icy worlds to search for life beyond Earth. A veteran of Antarctic fieldwork, she studies Earth’s ice shelves and glaciers to capture the impacts of changing climate and explore analogs for Europa. Britney played a central role in developing several mission concepts, including the recently selected Europa Multiple Flyby mission where she is Co-I on the REASON radar team. She is an associate of the Dawn Framing Camera team. She is PI of Sub-Ice Marine and Planetary Analog Ecosystems (SIMPLE), a $5M NASA program studying the McMurdo Ice Shelf using remote sensing and underwater vehicles. She leads the Georgia Tech built Icefin AUV for under ice

May 8, 2017 | Atlanta, GA

The annual EAS awards ceremony was held April 28, 2017.  The ceremony honors students and faculty for their accomplishments  throughout the academic year.  This year's awards went to:

 

Students

Mary Francis McDaniel: Rutt Bridges Undergrad Research Initiative

Kayla Duarte:  Rutt Bridges Undergrad Research Initiative

Chloe Stanton:  Quarter Century Award

Hongyu Guo:  Glen Cass Award

Lucas Liuzzo:  Research Excellence Award

Joshua Mendez Harper:  Best paper Award

Tiegan Hobbs:  Kurt Frankel Award

Ting Fang:  John Bradshaw Award

 

Faculty

Ellery Ingall

Judy Curry Award

Storm Photo Contest Winners

First Place: Dr. Robert Black - This is the picture on the main Slideshow
Second Place: Hongyu Guo
Third Place: Junwen Chen

May 19, 2017 | Atlanta, GA

Assistant Professor Chris Reinhard is the lead author on the study:  False Negatives for Remote Life Detection on Ocean-Bearing Planets: Lessons from the Early Earth, published in the Journal Astrobiology.

Inside Science has an article on the paper by Ramin Skibba.  Here in an excerpt:

To a distant observer peering through a telescope, even Earth would not have shown signs of life through most of its past. Despite the fact that our planet was teeming with mostly microscopic life for three billion years, levels of oxygen and methane -- gases often produced by metabolizing organisms -- would have been too low to be noticed from afar. This means that today's scientists on Earth might not be able to detect commonly assumed signs of extraterrestrial life, and they might give up on planets that are actually inhabited, according to a new study in the journal Astrobiology.

“There are huge swaths of time throughout Earth’s history during which it would’ve been difficult to see the presence of these metabolisms even though we know from the rock record that they were around. It’s a sobering thing,” said Christopher Reinhard, an Earth scientist at the Georgia Institute of Technology in Atlanta, and lead author of the study, who presented the research at a conference in Mesa, Arizona on April 27.

Bio

Dr. Chris Reinhard’s background is originally in evolutionary biology, but his past and current research is best characterized as falling under the label of 'deep time biogeochemistry' — He is fascinated and astonished by the observation that our planet has come to support a pervasive biosphere, and seek to reconstruct how we got here. This involves combining techniques from aqueous geochemistry, geology, and biogeochemical modeling in an effort to reconstruct Earth surface environments as they have changed over long timescales through Earth's deep history and how this evolution has been coupled with the evolution of microbial and macroscopic life. He received his Ph.D. in Earth Sciences from the University of California, Riverside in 2012 and joined Georgia Tech as an Assistant Professor in 2014.

 

May 26, 2017 | Atlanta, GA

Excerpt from Smoke from Wildfires Can Have Lasting Climate Impact

The wildfire that has raged across more than 150,000 acres of the Okefenokee Swamp in Georgia and Florida has sent smoke billowing into the sky as far as the eye can see. Now, new research published by the Georgia Institute of Technology shows how that smoke could impact the atmosphere and climate much more than previously thought.
 
Researchers have found that carbon particles released into the air from burning trees and other organic matter are much more likely than previously thought to travel to the upper levels of the atmosphere, where they can interfere with rays from the sun – sometimes cooling the air and at other times warming it.
 
“Most of the brown carbon released into the air stays in the lower atmosphere, but a fraction of it does get up into the upper atmosphere, where it has a disproportionately large effect on the planetary radiation balance – much stronger than if it was all at the surface,” said Rodney Weber, a professor in Georgia Tech’s School of Earth & Atmospheric Sciences.
 
The study, which was published May 22 in the journal Nature Geoscience, was sponsored by the NASA Radiation Sciences Program and the NASA Tropospheric Composition Program.
 
You can read the entire article here.
 
CITATION: Yuzhong Zhang, Haviland Forrister, Jiumeng Liu, Jack Dibb, Bruce Anderson, Joshua P. Schwarz, Anne E. Perring, Jose L. Jimenez, Pedro Campuzano-Jost, Yuhang Wang, Athanasios Nenes and Rodney J. Weber, “Top-of-atmosphere radiative forcing affected by brown carbon in the upper troposphere,” (Nature Geoscience, May 2017). http://dx.doi.org/10.1038/NGEO2960
 
Picture:  EAS Faculty members Rodney Weber (left) Athanasios Nenes (middle) and Postdoc Yuzhong Zhang (right)
 
Bios:
 
Rodney Weber
 
Dr. Rodney Weber obtained his Ph.D. in Mechanical Engineering in 1995 from University of Minnesota and joined Georgia Tech as an Assistant Professor in 1998. His areas of research include tropospheric aerosol particles and development of particle measurement systems. In 2010 he won the EAS Outstanding Faculty Research Author Award and recently the College of Sciences Faculty Mentorship award. Rodney is also a member of both American Association for Aerosol Research (AAAR) and American Geophysical Union (AGU).
 
Thanos Nenes
 
Dr. Athanasios Nenes, Professor in the School of Earth and Atmospheric Sciences, received his Ph.D. in Chemical Engineering from California Institute of Technology in 2002. He arrived at Georgia Tech in 2002 as an Assistant Professor and promoted to Professor in 2011. His research focuses on advancing the description of aerosols and aerosol-cloud interactions in atmospheric models through the combination of observations, theory and modeling. He is also heavily involved in field measurement programs (both ground-based as well as airborne) focusing on understanding the climate and health impacts of ambient aerosol from a wide variety of sources.  Dr. Nenes has recently been awarded the American Geophysical Union Ascent Award and the Georgia Institute of Technology Faces of Inclusive Excellence. 

June 26, 2017 | Atlanta, GA

More than 30 years after Voyager 2 sped past Uranus, Georgia Institute of Technology researchers are using the spacecraft’s data to learn more about the icy planet. Their new study suggests that Uranus’ magnetosphere, the region defined by the planet’s magnetic field and the material trapped inside it, gets flipped on and off like a light switch every day as it rotates along with the planet. It’s “open” in one orientation, allowing solar wind to flow into the magnetosphere; it later closes, forming a shield against the solar wind and deflecting it away from the planet.

This is much different from Earth’s magnetosphere, which typically only switches between open and closed in response to changes in the solar wind. Earth’s magnetic field is nearly aligned with its spin axis, causing the entire magnetosphere to spin like a top along with the Earth’s rotation. Since the same alignment of Earth’s magnetosphere is always facing toward the sun, the magnetic field threaded in the ever-present solar wind must change direction in order to reconfigure Earth’s field from closed to open. This frequently occurs with strong solar storms.

But Uranus lies and rotates on its side, and its magnetic field is lopsided — it’s off-centered and tilted 60 degrees from its axis. Those features cause the magnetic field to tumble asymmetrically relative to the solar wind direction as the icy giant completes its 17.24-hour full rotation.

Rather than the solar wind dictating a switch like here on Earth, the researchers say Uranus’ rapid rotational change in field strength and orientation lead to a periodic open-close-open-close scenario as it tumbles through the solar wind.

“Uranus is a geometric nightmare,” said Carol Paty, the Georgia Tech associate professor who co-authored the study. “The magnetic field tumbles very fast, like a child cartwheeling down a hill head over heels. When the magnetized solar wind meets this tumbling field in the right way, it can reconnect and Uranus’ magnetosphere goes from open to closed to open on a daily basis.”

Paty says this solar wind reconnection is predicted to occur upstream of Uranus’ magnetosphere over a range of latitudes, with magnetic flux closing in various parts of the planet’s twisted magnetotail.  

Reconnection of magnetic fields is a phenomenon throughout the solar system. It occurs when the direction of the interplanetary magnetic field – which comes from the sun and is also known as the heliospheric magnetic field – is opposite a planet’s magnetospheric alignment. Magnetic field lines are then spliced together and rearrange the local magnetic topology, allowing a surge of solar energy to enter the system.

Magnetic reconnection is one reason for Earth’s auroras. Auroras could be possible at a range of latitudes on Uranus due to its off-kilter magnetic field, but the aurora is difficult to observe because the planet is nearly 2 billion miles from Earth. The Hubble Space Telescope occasionally gets a faint view, but it can’t directly measure Uranus’ magnetosphere.

The Georgia Tech researchers used numerical models to simulate the planet’s global magnetosphere and to predict favorable reconnection locations. They plugged in data collected by Voyager 2 during its five-day flyby in 1986. It’s the only time a spacecraft has visited.

The researchers say learning more about Uranus is one key to discovering more about planets beyond our solar system.

“The majority of exoplanets that have been discovered appear to also be ice giants in size,” said Xin Cao, the Georgia Tech Ph.D. candidate in earth and atmospheric sciences who led the study. “Perhaps what we see on Uranus and Neptune is the norm for planets: very unique magnetospheres and less-aligned magnetic fields. Understanding how these complex magnetospheres shield exoplanets from stellar radiation is of key importance for studying the habitability of these newly discovered worlds.”

The paper, “Diurnal and Seasonal Variability of Uranus’ Magnetosphere,” is currently published in the Journal of Geophysical Research: Space Physics.

June 28, 2017 | Atlanta, GA

Xin Cao, Georgia Tech Ph.D. candidate & faculty member Carol Paty were published in the Journal of Geophysical Research: Space Physics.

Here is an excerpt from Georgia Tech News Center article by Jason Maderer:

“Uranus is a geometric nightmare,” said Carol Paty, the Georgia Tech associate professor who co-authored the study. “The magnetic field tumbles very fast, like a child cartwheeling down a hill head over heels. When the magnetized solar wind meets this tumbling field in the right way, it can reconnect and Uranus’ magnetosphere goes from open to closed to open on a daily basis.”
 
“The majority of exoplanets that have been discovered appear to also be ice giants in size,” said Xin Cao, the Georgia Tech Ph.D. candidate in earth and atmospheric sciences who led the study. “Perhaps what we see on Uranus and Neptune is the norm for planets: very unique magnetospheres and less-aligned magnetic fields. Understanding how these complex magnetospheres shield exoplanets from stellar radiation is of key importance for studying the habitability of these newly discovered worlds.”
 
The article can be read in its entirety here.
 
Biography:
 
Carol Paty
 
Dr. Carol Paty joined the School of Earth and Atmospheric Sciences in 2008. Her research is in the area of space and planetary scientist focused primarily on magnetosphere dynamics particularly as it pertains to the near-space environment of planetary bodies. She received her Ph.D. degree in Earth and Space Sciences from the University of Washington in 2006. She was a Postdoctoral researcher at the Southwest research Institute from 2006 to 2008.  
 
Links to Coverage on the paper:
 

July 17, 2017 | Atlanta, GA

Dr. Ken Ferrier, Assistant Professor in Earth & Atmospheric Sciences has received a two year grant from the American Chemical Society.  The research project being sponsored is titled: Sensitivity of Sea Level to Sediment Erosion and Deposition in Massive Sedimentary Systems

From the abstract:

As sea level rises and falls, the shorelines where rivers meet the ocean migrate landward and
seaward. This influences the locations of sedimentary deposits and organic carbon burial, as
well as the grain size of the deposited sediment. In this manner, changes in sea level regulate the
development of hydrocarbon reservoirs within marine sedimentary deposits. Understanding the
development of hydrocarbon reservoirs therefore requires a comprehensive understanding of the
processes that drive sea-level change.
 
The goal of the proposed research is to quantify sea-level responses to massive fluvial
sediment fluxes.
 
Biography:
 
Dr. Ken Ferrier is an assistant professor of geology in the School of Earth and Atmospheric Sciences at Georgia Tech. He holds an AB in Physics from Cornell University and a Ph.D. in Earth and Planetary Science from the University of California, Berkeley. At Georgia Tech, he teaches undergraduate and graduate students and also conducts research on a number of processes that shape the Earth’s surface.  At present, his group’s research is centered on two broad themes: 1) The topographic and chemical evolution of the Earth’s surface; and 2) sea level dynamics.

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