Fall 2013

An Update from our Students

By Meg Smith
Student Representative, UW Astrobiology Steering Group

This year has been an exciting one for astrobiology. As Mars Science Laboratory (Curiosity) slowly rolls across the surface of the red planet, there is increasing evidence that Mars may have once been habitable. If we turn our attention farther from Earth, NASA's Kepler Space Telescope has left scientists with a treasure-trove worth of data to sift through. UW Astrobiology graduate students are working on scientific research that will help us better interpret data and understand the environmental conditions and possibilities for life on other planets. Here is a sampling of questions our graduate students are trying to answer:

What was early Mars like?

Elena Amador has been sifting through satellite imagery of the martian surface to identify areas that once may have been water-rich and habitable. Meg Smith used a computer model to prove that perchlorates, strange salts discovered across the surface of Mars, probably did not form through chemical reactions in the atmosphere.

What mysteries does ice cover on other planets?

Jon Bapst is using data from a satellite that orbits Mars, to track the brightness of Mars' surface across a seasonal cycle. He thinks the changes in brightness may be due to ice on the surface. Meanwhile, new student Paul Kintner is developing instruments for a thermal ice drill. The drill will be used to bore into sub-glacial lakes in Antarctica. Such lakes might be similar to sub-glacial lakes on icy planets.

What was the early Earth like?

Eva Stueeken analyzed nitrogen isotopes in Mesoproterozoic (1.6-1.0 billion years ago) rocks and argues that eukaryotic organisms lived mostly in shallow water environments. To understand Earth's earliest environments, new student Matt Koehler will be measuring nitrogen isotopes in Archean (4.0-2.5 billion years ago) rocks, while new student Joshua Krissansen-Totton will be taking a computational approach to analyzing carbon isotopes in Archean rocks.

How did life take hold?

Rika Anderson has just completed her PhD, which focused on the diversity and evolution of microorganisms in hydrothermal vent systems. She also taught a summer course on astrobiology to students in Scotland. New student Chantz Thomas comes to the program having studied ribose-forming reactions at ice-vapor interfaces. Research like his can help us understand how life may have formed on Earth and if it could form on icy moons like Europa.

What are the limits for life?

Jeff Bowman and Evan Firth are studying microorganisms that live in sea ice. They hope to understand how such organisms survive, how they cycle elements, and how they might have evolved.

How do we recognize signs of habitability and life on distant worlds?

Amit Misra has developed a technique to measure atmospheric pressure on exoplanets. Eddie Schwieterman is working on developing novel models to determine what biogsignatures we might be able to observe on distant planets. Giada Arney has been observing Venus to refine measurements of its atmospheric composition. Hopefully methods like these will be used one day to observe extrasolar planets.

How do planets change over time?

Aomawa Shields used a climate model to show how planets that orbit cool stars are more resistant to global ice-ages than planets that orbit hot stars. Rodrigo Luger is using a computer model to see if Earth-size planets could be the remains of giant planets that lost their atmospheres to space. Matt Tilley is working to analyze how plasma from a star interacts with the atmospheres of planets. One application of his work is to understand how radio signals from planetary aurora could be observable. Russell Deitrick is studying orbital stability in multi-planet systems and is developing a model to understand how orbital dynamics influences the width, lifetime, and location of the habitable zone in these systems.

Photo: Graduate students visiting Hell Creek, Montana, for this year's workshop. Last row (left to right): Tom Tobin (ESS), , Amit Misra (Astronomy), Chantz Thomas (Chemistry), Matt Koehler (ESS). Middle row: Russell Deitrick (Astronomy), Megan Smith (ESS), Eddie Schwieterman (Astronomy), Paul Kintner (ESS), Brett Morris (Astronomy), Prof. Greg Wilson (Biology), Jon Bapst (ESS). Front row: Eva Stueeken (ESS), Wolf Clifton (Museology), Prof. Roger Buick (ESS), Josh Krissansen-Totton (ESS).

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