Research Helps Scientists Understand Dust Devils on Mars and Earth
August 5, 2008 - "It's a bit of an art - learning how to drive across dry lake beds at great speed," says Matt Balme. "And it can be quite hairy as well."
During the next three years, Balme will spend a lot of time careening across playas and other open, desert areas to better understand dust devils on Mars - how much dust they lift into the atmosphere and how this affects the Martian climate.
Dust devils look like miniature tornados, tossing up dust and debris, but the atmospheric conditions that cause them are very different. Dust devils are unrelated to storm systems. Instead, they form when ground temperatures are warmer than the surrounding air and moving air triggers a swirling column called a convective vortex.
Balme, a research scientist with the Planetary Science Institute (PSI) and a research fellow at Great Britain's Open University, is the lead investigator on a NASA-funded study designed to link meteorological data to the number and intensity of dust devils in an area. This data will then be plugged into Martian climate models to help scientists better understand the role of dust devils in shaping the Martian climate.
Similarly, the study will help scientists better understand the effect of Earth's dust devils on local or regional air quality and their role in transporting aerosols long distances.
The study also will generate data to test a host of equations that describe how dust devils form, that were recently developed by Nilton Renno, a University of Michigan professor who is working with Balme. The equations, which apply to everything from dust devils to cyclones, can determine the intensity of a convective vortex based on temperature, humidity, and the depth of the troposphere - the lower part of the atmosphere. These theories could help meteorologists predict the intensity of hurricanes and cyclones.
Since no grid of weather stations exists on Mars, scientists depend on computer models to study the climate. Balme hopes to make those models more accurate by using data from terrestrial dust devil observations as analogs for the Martian ones.
That's where racing across playas comes into play. The test setup includes three meteorology stations arranged in a triangle and a mobile sampling platform attached to the front of a 4WD truck. The weather stations will measure wind speed, air temperature and air pressure.
Researchers will race ahead of dust devils in the triangular area covered by the weather stations. Then they'll slam on the brakes and quickly lower the instruments to ground level to sample the dust devil's wind speeds, temperature, dust load, and size as the whirlwind passes over them.
"The good thing about having it attached to the truck is that if you miss the dust devil, you can quickly pick up the instruments and chase it down again," Balme said.
Mars is an extremely dusty place, Balme noted, and models suggest that dust devil activity might support the persistent dustiness of the planet's atmosphere. With more accurate modeling, scientists will better understand the effect of dust devils on the Martian climate.
Some data scaling is in order, however, because the Martian atmosphere is so much thinner than Earth's. While 50 mph is near the maximum velocity for terrestrial dust devils, their Martian cousins may spin at as much as 200 mph.
Balme cautions that no direct measurements have been made of dust devil speeds on Mars. So this is a theoretical number. But much higher wind speeds are needed to lift an equivalent amount of dust into the thin Martian air compared to Earth.
Mars also is much colder than Earth. While dust devils often are associated with hot deserts, they're just as likely to form in cold deserts, such as those found on Mars, Balme said. The triggering factors don't depend on absolute temperature, only on a difference in temperature.
"We've done lots of chasing," Balme added. "But chasing just gives you more information about dust devils." What's needed now is to link dust devil formation - how many occur and how intense they are - to the climatic conditions that cause them.
PSI Associate Research Scientist Steve Metzger will lead the field team in Nevada's Eldorado Valley, south of Las Vegas, while Renno will lead the tests at a crop-duster airstrip near Eloy, Ariz., about halfway between Phoenix and Tucson.
"The big thing about this project is we're not just going in and measuring dust devils," Balme said. "We want to be measuring the ambient meteorology at the same time. So having two different test areas gives us two different climatic regions to study."
PSI Research Scientist Asmin Pathare also will be involved in the field studies, and several researchers from Great Britain's Open University will be working on the project.
The Open University group will contribute an instrument that looks vertically into a dust devil to measure ultraviolet radiation. It will provide data on the exact location where measurements are taken within a dust devil and on the amount of dust it's carrying. The Open University scientists include Martin Towner, Manish Patel, Tim Ringrose, and Steven Lewis.
NASA's Mars Fundamental Research Program is funding the research.
In addition to the valuable scientific results, "It's going to be good fun," Balme said. "I really like going into the field and chasing dust devils!"
Two Asteroids Named for PSI Scientists
July 29, 2008 - Two asteroids have been named for Planetary Science Institute (PSI) researchers Keith Holsapple, of Seattle, Wash., and David O'Brien, of Tucson, Ariz.
The recently discovered asteroids are located in the inner region of the main asteroid belt, which is between the orbits of Jupiter and Mars.
20360 Holsapple honors Keith A. Holsapple, a PSI Senior Scientist and Professor of Engineering at the University of Washington. He is recognized for his work in modeling the response of planetary and asteroidal material to stress and shock. Holsapple also has developed scaling laws for cratering and has explored the relationship between asteroidal shape, spin rate and internal strength.
21774 O'Brien honors PSI Research Scientist David P. O'Brien for his studies of the collisional evolution of main-belt minor planets and cratering on 951 Gaspra and other objects. 951 Gaspra was the first asteroid visited closely by a spacecraft. O'Brien also was honored for his studies of primordial sculpting of the main asteroid belt during the planetary accretion process.
Edward Bowell, who discovered the asteroids, announced the new designations during the recent Asteroids, Comets, Meteors 2008 conference in Baltimore, Md. Bowell, an astronomer from Lowell Observatory in Flagstaff, Ariz., suggested the asteroids be named for Holsapple and O'Brien, and the names were then approved by the International Astronomical Union.
20360 Holsapple was discovered on May 1, 1998, and 21774 O'Brien on Sept. 3, 1999. They were found during the search for near-earth objects at the Lowell Observatory's Anderson Mesa Station, 12 miles south of Flagstaff.
Planetary Science Institute Researcher Brings Antarctic Meteorite Hunt to Classrooms
July 22, 2008 - Grade-schoolers in San Antonio, Texas are learning a lot about Antarctica and space science from PSI Research Scientist Les Bleamaster.Between Thanksgiving and the end of January, Bleamaster spent 48 days during Antarctica's "summer" hunting meteorites with the Antarctic Search for Meteorites (ANSMET) program.
Since returning, Bleamaster has taken his laptop and projector to several grade schools to talk about his experiences and to spark students' interest in science.
"It's amazing to go into a classroom of third graders and see their eyes get really big," Bleamaster says. "They see pictures of space and geologists doing work in the field. They see Antarctica, and they get really excited. I speak to other groups, too, but the presentations to grade schools; that's the best part of the whole job."
Bleamaster, a planetary geologist who creates geologic maps of Venus and Mars, uses the opportunity to educate students about geology, engineering, mathematics and the importance of the work being done by NASA and PSI.
He explains that planetary geology is much like Earth-based geology. Scientists need rock samples and pictures of the Earth's surface to unravel the story of how Earth formed and evolved.
The same procedures apply to the Earth's Moon, the planets, and other solar system bodies. "While spacecraft take the pictures, the big question is, 'If we want to study rocks from space where do we get them?'" Bleamaster said. "A big answer to that question is Antarctica."
Although meteorites don't fall on Antarctica any more often than on other parts of the globe, it's the perfect place to find them, he said. Rocks stand out on the vast, ice-blue landscape, and just about any rock sitting out on the ice had to drop from space. The rocks also don't deteriorate or weather after they land because they're preserved in what amounts to a gigantic, dry freezer.
In addition to collecting rocks on the ice sheet, Bleamaster and the other ANSMET crewmembers searched along the natural barricade formed by the Trans-Antarctic Mountains. The ice gets pushed up against the mountains, sublimates and leaves the meteorites behind.
The ANSMET group - which included scientists from China, the Netherlands, Arizona, Indiana, Ohio, Maryland and Texas - camped out in six tents in temperatures ranging from 10 below zero to 25 degrees Fahrenheit.
They either searched on foot or rode snowmobiles while looking for meteorites. When they found a meteorite (the team bagged 70 on its best day), the rocks were carefully collected and numbered. Team members recorded the GPS location and locked the meteorite in a box to be transported to Johnson Space Center for analysis.
Those were the good days. On bad days, winds screamed across the ice at 50 knots, and the scientists hunkered down in their tents. During one storm, they stayed tent-bound for nearly five days.
"That 4.5 days in the tent was pretty emotionally wrecking," Bleamaster said. "Fortunately, I had a solar panel to charge my iPod. That was a lifesaver."
Living in tents, not showering for 48 days, dealing with constant cold, and enduring storms, coupled with long days of hard physical labor, made this adventure much more difficult than the usual field trip. Isolation, with the closest human beings more than 100 miles away, also was draining. "I missed my wife and kids tremendously," Bleamaster said.
"If someone had asked me in February whether I would do this again, I would have said, 'Absolutely not,'" Bleamaster added. "But now, with a little reflection, I'm getting to the point where I probably would consider going again if there's the opportunity."
The ANSMET program, which is funded by the National Science Foundation and led by principal investigators from Case Western University, has been making annual trips to Antarctica since the 1976. During that time, ANSMET has missed only one year and collected nearly 20,000 meteorites, including the famous Allan Hills meteorite from Mars.
ANSMET's most important finds include a handful of meteorites that have generated more than 600 research studies since 1988.
"This is what I try to hammer home to the second graders," Bleamaster said. "Some of these are the oldest rocks we have. We don't have rocks on Earth from 4.5 billion years ago. These meteorites are the building blocks of the solar system. Studying them lets us really get at the origins of the solar system."
Jeff Morgenthaler Joins the Planetary Science Institute
July 22, 2008 - Jeff Morgenthaler has joined the Planetary Science Institute (PSI), a private, non-profit corporation, with headquarters in Tucson, Arizona.
He will be based in Fort Kent, Maine.
Morgenthaler studies space plasmas, the interstellar medium, the near-space environments of planets, and comets. He specializes in developing instruments for ground-based telescopes, such as novel spectrometers and imaging systems. He also creates data analysis software for these instruments.
Morgenthaler's first project at PSI uses the Galaxy Evolutionary Explorer (GALEX) space telescope to study Comet 8P/Tuttle - a short-period Halley-family comet and primordial leftover from the solar system's formation billions of years ago.
Comets are of interest because they may have been important sources of water that formed the Earth's oceans and organic material, contributing to the rise of life.
The California Institute of Technology operates GALEX for NASA.
Morgenthaler also is studying a plasma ring that surrounds Jupiter in the orbit of Io, one of its moons. Volcanoes create a thin atmosphere on Io, which is the most volcanically active body in the solar system. This ionized atmosphere is swept away by Jupiter's powerful magnetic field to form a glowing ring, which is called the "Io plasma torus." A plasma is an ionized gas, and an ion is an atom or molecule that carries an electrostatic charge because it has gained or lost one or more electrons.
The Io plasma torus is the closest astrophysical nebula (cloud of gas or dust) to the Earth. By studying it in detail, using measurements from spacecraft, scientists can test their models of similar systems, such as disks around newly forming stars, binary star systems and super-massive black holes in the centers of galaxies. Morgenthaler's work on the Io plasma torus is supported by NASA's Planetary Astronomy Program.
Morgenthaler is also studying X-rays coming from outer space. A portion of these X-rays is generated by a charge-exchange reaction between highly charged ions in our solar wind and neutral hydrogen atoms sifting into our solar system from interstellar space. Scientists think another portion of the X-rays may come from hot plasma generated by supernova explosions within a few hundred parsecs of our solar system (the "local bubble"). Morgenthaler's work, an extension of his Ph.D. thesis studies, will help separate what portion of the X-rays is generated by each mechanism.
Morgenthaler began observing solar-system objects at the McMath-Pierce solar telescope at Kitt Peak National Observatory near Tucson, Ariz. in 1997 and has spent at least two weeks each year observing on the mountain since then.
He worked as a research scientist at the University of Washington in Seattle until moving to Maine earlier this year.
Morgenthaler earned his undergraduate degree in physics from MIT in 1990, and his Master's (1994) and Ph.D. (1998) degrees in physics from the University of Wisconsin.
Planetary Science Institute Wins More Than $5 Million in NASA Research Grants
July 14, 2008 - Scientists at the Planetary Science Institute (PSI) have won more than $5 million in NASA research grants so far in 2008. PSI is a private, non-profit corporation engaged in the exploration of the solar system. PSI is headquartered in Tucson, Arizona.
The 24 funded projects, which are led by 18 PSI scientists, focus on topics that range from mapping landing sites for a Mars science laboratory to determining the densities of comets. The projects also include simulating weathering effects on the Earth's moon, exploring the topography of selected Saturn moons and studying the geologic history of light-toned layered deposits found in a Martian canyon system.
"The competition for these grants within the scientific community is intense, and winning them is testimony to the quality of PSI investigators and their work," said PSI Director Mark Sykes.
"The grants also reflect the mutual support that our scientists provide to one another in order to maximize everyone's success, even on projects in which they're not directly involved," Sykes added. "That kind of support and collaboration is part of what makes PSI a very special place."
Five grants were awarded in the Mars Data Analysis Program for a total of $800,000. An additional five grants, totaling $1.3 million, came from the Planetary Geology and Geophysics program. And another three grants, totaling $900,000, came from the Mars Fundamental Research program.
Several other grants were awarded for projects involving space missions such as NASA's Cassini-Huygens Mission to Saturn, the Dawn mission to the asteroid belt to study the asteroid Vesta and small planet Ceres, and the Japan Aerospace Exploration Agency's Hayabusa mission to a near-Earth asteroid.
"The diversity of research being pursued through these grants, as well as the concentration of PSI scientists in certain research programs, illustrates the important contributions the Institute continues to make in expanding our understanding of the solar system," Sykes said.
Descriptions of the projects can be found at: http://www.psi.edu/research
The grants were awarded to the following PSI scientists: Paul Abell, Natasha Artemieva, Matthew Balme, Mary Bourke, David Crown, Donald R. Davis, Robert W Gaskell, William K. Hartmann, Keith Holsapple, Kimberly Kuhlman, Melissa Lane, Asmin Pathare, Thomas H. Prettyman, Nalin Samarasinha, Edward F. Tedesco, Stuart J.Weidenschilling, Catherine Weitz, and Rebecca Williams.
The Planetary Science Institute is a private, nonprofit corporation founded in 1972 and dedicated to solar system exploration. It is headquartered in Tucson, Arizona.
PSI scientists are involved in numerous NASA and international missions, the study of Mars and other planets, the Moon, asteroids, comets, interplanetary dust, impact physics, the origin of the solar system, extra-solar planet formation, dynamics, the rise of life, and other areas of research. They conduct fieldwork in North America, Australia and Africa. They also are actively involved in science education and public outreach through school programs, children's books, popular science books and art.
The Institute's researchers are based in 15 states, the United Kingdom, Russia, Switzerland and Australia.