EPSS Colloquium - winter-2022


The DAVINCI Discovery Mission to Venus

Jan. 11, 2022
3:30 p.m. - 5 p.m.
Zoom

Presented By:

  • James Garvin - Goddard
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Seminar Description coming soon.

Recent Glaciation on Mars: Stubbornly Cold-Based or Reluctantly Wet-Based?

Jan. 18, 2022
3:30 p.m. - 5 p.m.
Zoom

Presented By:

  • Frances Butcher - U. Sheffield
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In the present day, Mars' mid-to-high latitudes host abundant water ice within diverse glacial landscapes, including in buried glaciers. In this talk, we will explore the recent history of glaciation on Mars and its place within the story of water on the Red Planet. Have Mars' glaciers always been frozen under stubbornly cold climate conditions, or did they ever produce meltwater? I will present recent discoveries which suggest some of Mars' glaciers produced meltwater at their beds (at least transiently) and explore the implications for the recent thermal environment on Mars.


The Search for Chiral Asymmetry as a Potential Biosignature in our Solar System

Jan. 25, 2022
3:30 p.m. - 5 p.m.
Zoom

Presented By:

  • Daniel Glavin - Goddard
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EnVision: a journey from London’s sewers to the surface of Venus

Feb. 1, 2022
3:30 p.m. - 5 p.m.
Zoom

Presented By:

  • Richard Ghail - Royal Holloway, University of London
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Interferometric measurements from orbiting radar, which 30 years ago so dramatically revealed ground movements associated with the Landers earthquake, has evolved into a routine ground engineering monitoring tool able to measure the subtle movements caused by tunnelling and dewatering. At up to 90 metres deep, London's Tideway Tunnel provided the perfect opportunity to test the limits of the technique. The results proved stunningly far from mundane, identifying ongoing geological fault movements an order of magnitude smaller than ever previously measured, in a location where such movements were completely unexpected and yet entirely predictable. Moreover, they demonstrated that here was a tool capable of determining from orbit whether Venus is as active as Earth or as dead as Mars, a key measure in understanding why our 'twin' planet is so different to our own. The discoveries in London also reveal a new way of understanding the geology of our nearest neighbour that resolves the paradox of its impact crater distribution. This talk discusses how EnVision overcame technical challenges and overturned a geological paradigm to win the M5 selection.


From life to rock: assessing biogenicity in Earth's early rock record and Martian rock samples

Feb. 8, 2022
3:30 p.m. - 5 p.m.
Zoom

Presented By:

  • Mark van Zuilen - Laboratoire Géosciences Océan (LGO)
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Traces of life in the ancient Earth’s rock record are difficult to interpret because early life forms had attained only a low degree of complexity, their remnant partially broke down, and there were abiologic processes that could have generated ‘non-living’ forms of a similar degree of complexity. Tests of biogenicity therefore involve multiple biosignature characteristics, as well as criteria related to geological context and to various forms of contamination. It is, however, debatable how many criteria need to be satisfied to decisively detect life, since it is easy to generate false positives or false negatives. The qualitative nature of many individual biosignatures adds further ambiguity, as they are often not standardized and depend on individual interpretations. The other problem is that many criteria require a yes/no answer, while in reality there is only a certain probability for life or a certain improbability for non-life. In order to overcome this inherent uncertainty in life detection, several recent studies have expressed the specific need for a more quantitative approach in data treatment. Such a development would also be important for the search for possible traces of remnant life on Mars. I will here discuss some typical biosignature controversies related to the interpretation of microfossils and microbialites, and will present a recent example of a quantitative approach – based on statistical morphometry – to determine the biogenicity of populations of microstructures.


Searching for Signs of Life and Its Origin on Other Worlds

Feb. 15, 2022
3:30 p.m. - 5 p.m.
Zoom

Presented By:

  • Laurie Barge - JPL
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Is there life elsewhere in the solar system, and if so how can we find it? Although Earth provides a variety of examples of what biology can look like, examples of the critical steps between abiotic and biotic systems are lacking because the prevalence of life on our planet has erased its record of prebiotic conditions. The distinction between biotic and abiotic is still often unclear, since we are still learning about the limits of life, and also because abiotic chemistry can become more complex when devoid of biological influence. However, prebiotic chemistry may still be a current or formerly active process on other worlds with detected chemical gradients and organics, such as Enceladus, Ceres, or Mars. In this talk I will discuss how astrobiologists approach the search for life on other planets, and describe some of the difficulties in distinguishing living and non-living systems. In particular, I will share some of our group’s lab work on simulating prebiotic chemical systems that aim to bridge the gap between geochemistry and biochemistry, and will discuss some of the challenges in characterizing such systems using mission-relevant instruments.


Determining Geometry and Predicting Topography: modeling the kinematic, thermal and landscape evolution of central Himalaya

Feb. 22, 2022
3:30 p.m. - 5 p.m.
Zoom

Presented By:

  • Nadine McQuarrie - University of Pittsburgh
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Paleoclimate

March 1, 2022
3:30 p.m. - 5 p.m.
Zoom

Presented By:

  • Kim Cobb - Georgia Tech
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Seminar Description coming soon.