University of Washington Astrobiology Program

Fall 2012

An Update from our Students

By Rika Anderson

Student Representative, UW Astrobiology Steering Group

As an inherently interdisciplinary field, astrobiology is a melting pot of many varied scientific endeavors, a gathering point for scientists who are motivated by an insatiable curiosity about the universe. The students in the astrobiology program at the UW represent a microcosm of this global astrobiology community: we represent departments from all corners of campus, but we are united in our passion for answering fundamental questions. Here is but a sampling of our latest undertakings:

In the realm of the stars and planets, students aim to understand how planets form, and how we can study the planets that are rapidly being discovered outside of our solar system. Giada Arney is measuring gases in Venus' atmosphere, because Venus-like planets are probably common in the universe. These hot planets lie just beyond the inner edge of the “habitable zone” where liquid water can exist on a planet's surface, and she wants to understand exactly what defines the inner edge of that zone. Eddie Schwieterman is making models to envision how Earth-like planets with higher atmospheric pressure might look to faraway observers, while Amit Misra is working on ways to study the atmospheric composition of exoplanets that we observe crossing the face of their star: the most successful means yet of discovering exoplanets. By studying planetary atmospheric composition, we may get hints as to what processes - such as life - might be operating on their surface. His colleague Aomawa Shields is studying the ways in which the energy emitted by stars can affect the climate of planets, especially planets covered in ice. She has just submitted a paper to the journal Astrobiology that reports that planets around redder, cooler stars appear less sensitive to changes in the amount of stellar radiation coming from a star than planets around hotter, brighter stars. “Planets around hot stars can actually be quite cool, and not so nice for life on the surface!” she says.

But habitability is determined by more the amount of solar radiation a planet gets - space weather and magnetic fields may play a role too. First year student Matt Tilley plans to investigate how the magnetic fields of extrasolar planets can interact with the stars they orbit, and how that can affect planetary detection and habitability. Meanwhile, recent AB grad Michele Cash is now at CU Boulder at NOAA's Space Weather Prediction Center, and is trying to improve the way we forecast space weather events, hoping to predict events such as solar wind shocks before they hit the Earth.

Closer to home, Curiosity has landed on Mars - and we are following it closely. Wayne Stewart plans to use data gathered by the rover to study the geology of the Glenelg basin in Gale Crater. Wayne will explore the possibility of the prior existence of an intermittent lake at Glenelg. Meanwhile, Jon Bapst is constructing a Mars simulation chamber to simulate Martian pressure, temperature, and humidity with Martian soil simulant - a little piece of Mars here on Earth. And here on our own planet, Eva Stueeken studied sulfur concentrations in marine sediments to demonstrate that microorganisms may have colonized the land, and therefore controlled biogeochemical cycles, as far back as 2.8 billion years ago. This work was recently published in Nature Geoscience. Last summer, she collected 1.5 billion-year-old rocks from western Montana to further investigate the evolution of the nitrogen cycle, while Kyle Costa trekked to the Atacama desert to understand how rainfall events impact the movement of salts in one of the driest places on Earth. We have students studying microbial processes both high and low: David Smith, who defended his PhD this fall and is heading for a new job at Kennedy Space Center, studied the transport and survival of microbes high in the stratosphere, while Rika Anderson visited deep-sea hydrothermal vents to find out whether microbes and viruses are swapping genes as a way to survive in the deep, dark places of our planet. And a collaboration of many astrobiology students, including Eva Stueeken, Rika Anderson, and Jeff Bowman as well as former students Jesse Colangelo-Lillis, Billy Brazelton, Sanjoy Som, and Aaron Goldman in conjunction with professor John Baross, has produced a paper arguing that the origin of life on our planet could not have happened in a single setting, but rather relied on the multiplicity of environments offered by the entire planet 4 billion years ago.

As staggering as this synopsis may seem, it represents but a fraction of the research conducted by the students in our program. With 23 students in total, our research spans the range from space physics to planetary geology to extreme microbiology, and yet through the program we aim to bring our work together to find common ground, hoping to gain insights into the nature of life in the universe.

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Photo: Graduate students Eva Stueeken, Michele Cash, Sanjoy Som, Regina Carns, and Rika Anderson atop the Kelso Sand Dunes in the Mojave Desert during a field workshop.

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