ASU instruments help scientists probe ancient Mars atmosphere

September 2, 2015

Mars was not always the arid Red Planet that we know today. Billions of years ago it was a world with watery environments — but how and why did it change?

A new analysis of the largest known deposit of carbonate minerals on Mars helps limit the range of possible answers to that question. False-color image showing carbonate deposits in Nili Fossae on Mars An area named Nili Fossae contains the richest deposit of carbonate minerals on Mars. If the carbon dioxide in its rocks were released, it would about triple the density of Mars' present atmosphere. New work using data from ASU instruments and others on NASA orbiters suggests that either Mars has yet-undiscovered reservoirs of carbonate rocks — or the planet may have seen flowing water despite having a thin, cold atmosphere. This THEMIS image uses false colors to show where the surface has loose materials such as sand or gravel (cool colors) and where the ground is tougher and rockier (warm tones). The scale bar is 12 miles long. Photo by: NASA/JPL-Caltech/Arizona State University Download Full Image

The Martian atmosphere currently is cold and thin — about 1 percent of Earth's — and almost entirely carbon dioxide. Yet abundant evidence in the form of meandering valley networks suggests that long ago it had flowing rivers that would require both a warmer and denser atmosphere than today. Where did that atmosphere go?

Carbon dioxide gas can be pulled out of the Martian air and buried in the ground by chemical reactions that form carbonate minerals. Once, many scientists expected to find large deposits of carbonates holding much of Mars' original atmosphere. Instead, instruments on space missions over the past 20 years have detected only small amounts of carbonates spread widely plus a few localized deposits.

The instruments searching for Martian carbonate minerals include the mineral-detecting Thermal Emission Spectrometer (TES) on NASA's Mars Global Surveyor orbiter and the Thermal Emission Imaging System (THEMIS) on NASA's Mars Odyssey orbiter. THEMIS' strength lies in measuring and mapping the physical properties of the Martian surface.

Both instruments were designed by Philip Christensen, Regents' Professor of geological sciences in ASU's School of Earth and Space Exploration. TES fell silent when NASA lost contact with Mars Global Surveyor in 2006, but THEMIS remains in operation today.

"We designed these instruments to investigate Martian geologic history, including its atmosphere," Christensen said. "It's rewarding to see data from all these instruments on many spacecraft coming together to produce these results."

Other instruments involved in the search include the mineral-mapping Compact Reconnaissance Imaging Spectrometer for Mars and two telescopic cameras on NASA's Mars Reconnaissance Orbiter.

Big, but not big enough

By far the largest known carbonate-rich deposit on Mars covers an area at least the size of Delaware, and maybe as large as Arizona, in a location called Nili Fossae. But its quantity of carbonate minerals comes up short for what's needed to produce a thick atmosphere, according to a new paper just published online in the journal Geology.

The paper's lead author is Christopher Edwards, a former graduate student of Christensen's. He is now with the U.S. Geological Survey in Flagstaff, Arizona. Both TES and THEMIS contributed to the work, he said.

"The Thermal Emission Spectrometer told us how much Nili has of several kinds of minerals, especially carbonates," Edwards noted.

And, he added, "THEMIS played an essential complementary role by showing the physical nature of the rock units at Nili. Were they impact-shattered small rocks and soil? Were they fractured and cemented rocks? Or dunes? THEMIS data let us differentiate these units by composition."

Bethany Ehlmann of the California Institute of Technology and NASA's Jet Propulsion Laboratory is Edwards' co-author. She said Nili doesn't measure up to what's needed. "The biggest carbonate deposit on Mars has, at most, twice as much carbon within it as the current Mars atmosphere.

"Even if you combined all known carbon reservoirs together," she explained, "it is still nowhere near enough to sequester the thick atmosphere that has been proposed for the time when there were rivers flowing on the Martian surface."

Edwards and Ehlmann estimate that Nili's carbonate inventory, in fact, falls too short by at least a factor of 35 times. Given the level of detail in orbital surveys, the team thinks it highly unlikely that other large deposits have been overlooked.

Atmosphere going, going, gone

So where did the thick ancient atmosphere go?

Scientists are looking at two possible explanations. One is that Mars had a much denser atmosphere during its flowing-rivers period, and then lost most of it to outer space from the top of the atmosphere, rather than into minerals and rocks. NASA's Curiosity Mars rover mission has found evidence for ancient top-of-atmosphere loss, but uncertainty remains just how long ago this happened. NASA's MAVEN orbiter, examining rates of change in the outer atmosphere of Mars since late 2014, may help reduce the uncertainty.

An alternative explanation, favored by Edwards and Ehlmann, is that the original Martian atmosphere had already lost most of its carbon dioxide by the era of rivers and valleys.

"Maybe the atmosphere wasn't so thick by the time the valley networks formed," Edwards suggested. "Instead of Mars that was wet and warm, maybe it was cold and wet with an atmosphere that had already thinned."

How warm would it need to have been for the valleys to form? It wouldn't take much, Edwards said.

"In most locations, you could have had snow and ice instead of rain. You just have to nudge above the freezing point to get water to thaw and flow occasionally, and that doesn't require very much atmosphere."

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

Robert Burnham

Science writer, School of Earth and Space Exploration


For some ASU students, journalism is all in the family

September 2, 2015

It’s a natural inclination for children to want to follow in their parents’ professional footsteps.

But what about when those steps are walking a path toward a challenged industry that has been downsized and fragmentized in recent years? That’s the question children of journalists have to ask themselves as they consider entry to a profession that has been just steps away their entire lives. Christina and Deboria Sedillo Dugan Christina Dugan (left) followed her mother Deborah Sedillo Dugan into journalism after finishing in 2013 with a degree through the Walter Cronkite School of Journalism and Mass Communication. The younger Dugan is working in Los Angeles for People magazine while her mother is the station manager at PHXTV for the City of Phoenix. Download Full Image

It’s also a concern for the parents of several second-generation journalists-in-training at Arizona State University’s Walter Cronkite School of Journalism and Mass Communication.

“It was such a fun career, and journalism has opened the door to so many wonderful things in my life,” said Deborah Sedillo Dugan, a pioneering Hispanic reporter, producer, news host and the mother of Cronkite School alum Christina Dugan. “How could I tell my daughter not to go down that same path knowing the adventure that awaited her?”

Despite industry challenges, the draw and passion are still there for the children and family members of journalists. Whether it’s a trend or coincidence, ASU’s Cronkite School has seen more than its fair share of families graduate from journalism education.

“I think it’s inherent that your children initially resist what their parents do for a living … but our children grow up in newsrooms and get that stimulation in their blood early on,” said Kristin Gilger, associate dean and professor of practice at the Cronkite School. Her daughter Lauren is an on-air reporter for the ABC affiliate in Phoenix.

“Sometimes it just takes a while for the lights to go on.”

Growing up in a newsroom

Christina Dugan knew how a newsroom operated by the time she was 10 years old.

She spent plenty of hours during her youth sitting underneath her mother’s desk at WTTG and the AFL-CIO in Washington, D.C., listening to keyboards clacking, reporters working the phones and news anchors rehearsing their lines, and witnessing firsthand how a half-hour TV news program was assembled.

“It looked more exciting than intimidating because there was always something exciting going on,” Dugan said. “The intensity level was always high.”

Despite the intensity, her mother, Deborah, always maintained her cool. She had to. As one of the first Latinas that graduated from American University with a broadcast journalism degree, Deborah started her career in 1981 at WRC-TV in the nation's capital and had to subtly find her place.

“It was very much like ‘Anchorman,’ ” Deborah said, referencing the Will Ferrell comedy about chauvinistic TV news culture. “Men dominated the industry, openly smoked in the newsroom and the three-martini lunch still existed.”

But times have changed and journalists like Deborah, who is now the station manager for PHXTV for the City of Phoenix, helped move the needle forward.

Deborah worked long hours, was given more responsibility and took on many different duties — including stints as an on-air host, anchor and producer — to advance up the ranks. Her work was rewarded with an Emmy nomination and several other broadcasting honors throughout the years.

It would have been easy for Deborah to use her connections find a job for Christina after she earned her degree in 2013, but Mom made a conscious decision not to interfere.

“She’s my daughter, but everything she’s accomplished she’s done on her own,” Deborah said. “She’s very poised, charming and pleasant.”

Those attributes are necessary for success, said Christina, who has been writing for People magazine since January 2013. She also said the Cronkite School prepared her well for the real world.

“The instructors at Cronkite told students exactly how it was, and they didn’t sugarcoat anything regarding journalism,” Christina said. “I’ve always enjoyed telling stories so journalism seemed like a good fit for me. It’s never been about the money but about passion, and it’s paying off.”

While mother and daughter lines have not been blurred, Deborah said she enjoys going with her daughter on assignments and watching her work.

“We went to a photo exhibit where Michael Keaton, Demi Moore and Robin Wright were in attendance and Christina was very poised while I got a little starstruck,” Deborah said. “It was a very proud moment for me.”

Understanding the pull

Cronkite School sophomore Skye Merida has two journalists in the family to whom he can go for advice.

His father, Kevin Merida, is a managing editor at the Washington Post, and his mother, Donna Britt, is a Pulitzer Prize-nominated reporter, nationally syndicated columnist and the author of “Brothers (& Me): A Memoir of Loving and Giving.”

Skye admits his home life had some influence on his decision to study journalism, but the late ESPN anchor Stuart Scott was the one who put the fire in his belly.

“Stuart Scott is a captivating presence and the kind of guy you looked at and said, ‘This man really enjoys his job,’ ” Skye said. “He brought honor to sports broadcasting, and he had the career that I want to emulate.”

But it was his parents’ responsibilities that clued Skye into the life of a working journalist, where any day’s schedule can be interrupted by the breaking news, like, say, the assassination attempt of U.S. Rep. Gabrielle Giffords in Tucson. Skye was with his father in Washington, D.C., when the story broke.

“We were going to have lunch that day, but before we did my dad had to stop into the Post to drop off something quickly. The story broke and that it was it … we were there all night,” Skye said. “That incident showed me that anything can happen at any time and as a journalist, you have an obligation to stop what you’re doing and cover the story.”

In his freshman year, Skye rolled up his sleeves and got to work. He joined the Blaze online, ASU’s alternative radio station, as a co-host of “Traffic Jam,” which covers news, sports, politics, movies and music. He also produced “Bottom of the 6th,” a sports radio show that airs Mondays through Thursdays from 6:30 to 7 p.m., covering all ASU sporting news as well as top national sports headlines.

“I’m so thankful to ASU for giving me this experience right out of the gate,” Skye said. “They’re putting me to work, and I love every day here.”

Skye’s mother said her son not only has the talent but a real passion she can get behind, even in a changing industry.

“He (Skye) lives and breathes sports,” Donna said. “He knows the facts, statistics, and rankings — not just for one or two sports — everything in between except curling. He gets to live it 24/7, and that’s the only way to live your life.”

An uncommon bond

It took some time for Lauren Gilger to understand she was a journalist at heart.

She was a dual major at Fordham University in New York and was studying French and visual arts when she applied for a Rhodes scholarship in 2009 and was asked to write a paper basically blueprinting the rest of her life.

It turned out to be a soul-searching “manifesto.”

“I wrote that I wanted to do something creative, fun and effective,” Gilger said. “To have impact and do good in the world.”

She had done plenty of odd jobs in the past, but nothing stimulated her more than being in a newsroom. Gilger had done internships for the New Times and East Valley Tribune — writing food and culture blogs for the former; and crime, features and obituaries for the latter.

Her mother, Kristin, an editor with the Times-Picayune in New Orleans and the Arizona Republic before joining the Cronkite School team, remembers the phone call when Lauren decided it was no use resisting.

“She said, ‘OK, Mom, you win,’ ” Kristin said, laughing. “I want to be a journalist.”

Lauren received her master's in mass communications at the Cronkite School in May 2011, where she graduated with a 4.0 GPA and was named the Outstanding Graduate Student. That same year she went to work at ABC 15 News (KNXV-TV) in Phoenix, where she is now a business reporter.

Her work has fallen in line with those early goals of wanting to have impact and do good in the world.  

Lauren’s reporting on an acceleration defect in Ford Escapes compelled one of the world’s largest automakers to recall more than 700,000 SUVs. And her stories exposed the backlog of untested rape kits in Valley police departments forced them to change their protocol.

The dogged work earned Lauren a George Foster Peabody Award and an Edward R. Morrow Award.

But the biggest award, her mother said, is the bond the two share as journalists.

“The same passions we share have been ignited by journalism,” Kristin said. “We talk about the state of the industry, the ups and downs of the newsroom, and the pressures of the profession. It has brought us closer because we share that.”

Reporter , ASU News