EUROPEAN ASTROBIOLOGY INSTITUTE 

EAI on-line seminar: EXPLORING THE SUBSURGFACE ENVIRONMENT OF MARS AND EUROPA

Ana Catalina Plesa, German Aerospace Centre

Tuesday, 1 December 2020, 16:00 CET (15:00 UTC)


The subsurface environments of Mars and Europa are important targets for planetary exploration due to their high astrobiological potential. On Mars, observations from orbiting spacecrafts and in-situ measurements by rovers and landers show evidence that liquid water was present at the surface and in the subsurface of Mars. The presence of water throughout the early evolution and in transient episodes during later times has important implications for the habitability of the planet. On Jupiter’s moon Europa, subsurface brine pockets or mushy regions may be present. If stable over geological time scales, they may provide niches for the ice shell habitability. Such environments, where liquid water may exist in the subsurface of Mars and Europa, may be located at kilometers depth. Measurements from planetary missions, however, mostly sample the surface and the very shallow subsurface and often provide only indirect constraints for the deep subsurface. Albeit these difficulties, physical processes that are relevant for the interior of planets and for the ice shells of moons in the Outer Solar System can be investigated  using numerical simulations. In this presentation, I will focus on the dynamics of Mars’ deep interior and of Europa’s ice shell to provide implications for their subsurface, where liquid water may be stable today. Combined with laboratory measurements and data from space missions, thermo-chemical evolution models can help to characterize the subsurface of Mars and Europa and to identify regions of interest for future planetary exploration.  The lecture is available at Youtube: https://youtu.be/5rFw5lpW3Qk



EAI on-line seminar: AGNOSTIC BIOSIGNATURES: LOOKING FOR LIFE AS WE DON´T KNOW IT

Heather Graham, Agnostic Biosignatures Lab, USA

Tuesday, 12 January 2021, 16:00 CET (15:00 UTC)


Current strategies for biosignature detection rely mainly on identification of well-established and widely accepted features and signatures associated with the biologic processes of life on Earth, such as particular classes of molecules and isotopic signatures, enantiomeric excesses, and patterns within the molecular weights of fatty acids or other lipids. As we begin to explore icy moons of Jupiter and Saturn and other destinations far beyond Earth, methods that identify unknowable, unfamiliar features and chemistries that may represent processes of life as-yet unrecognized become increasingly important.  Life detection without presumption of terran characteristics presents a formidable challenge to any astrobiology strategy. How do we contend with the truly alien? “Agnostic” approaches to biosignature and life detection are designed to target generic characteristics of life that distinguish it from abiotic chemistry. These methods require us to utilize existing instrumentation in more general ways, pursue new leads, and synthesize data with probabilistic approaches, since agnostic methods may trade definitiveness for inclusivity. This talk will outline some of the approaches under investigation in the Laboratory for Agnostic Biosignatures, discuss potential paths towards “agnostification”, and address some of the methodological problems and knowledge gaps posed by the problem of considering novel indications of life.

The lecture will be streamed at: https://www.gotomeet.me/EAI_online



EAI on-line seminar:,CLIMATE EVOLUTION OF ROCKY PLANETS AND THE IMPACT OF LIFE

Dennis Höning, VU Amsterdam, The Netherlands

Tuesday, 17 November 2020, 16:00 CET (15:00 UTC)


The habitability of rocky planets depends on atmospheric greenhouse gases, which are controlled by complex interactions between the mantle, crust, and atmosphere. On Earth, the long-term carbonate silicate cycle is known to regulate the climate over millions of years and may even be the reason why liquid water has existed on Earth’s surface since its early history. The application of global carbon cycle models to extrasolar planets is not straightforward, since the tectonic and geological state of these planets is unknown. In this talk, I will present climate evolution models for stagnant-lid and plate tectonics planets. In particular, I will discuss the role of the planetary interior, such as mantle temperature and composition. Planets with a global surface water layer will also be considered. Finally, the impact of biological processes, such as biological enhancement of weathering and marine biogenic calcite precipitation, on climate evolution and stability will be discussed.


You can view the lecture via the following link at Youtube:

https://youtu.be/brj0Q8B1ods



EAI on-line seminar:,MICROORGANISMS IN THE DEEP BIOSPHERE – RELEVANCE FOR THE SEARCH FOR LIFE ON OTHER PLANETS AND MOONS

Jean-Pierre de Vera, German Aerospace Centre

Tuesday, 3 November 2020, 16:00 CET (15:00 UTC)


On Earth life has colonized nearly all continents and oceans from the high altitudes in mountain ranges to the deepest regions of the oceans. Life has also adapted to all climate zones from the polar to the tropic latitudes. But often we forget to take into consideration the subsurface or deep subsurface as potential deep habitats. This lecture will give insights in the definition and nature of a hidden world, the so-called deep Biosphere which extends from the surface-connected subsurface via the shallow subsurface down to the deep subsurface. The total extension could reach several hundred meters to in maximum several kilometers below the surface and the ocean floor. Examples will be given on discoveries of specific habitable environments in the deep subsurface inhabited by specific extremophiles. Also, the resources will be shown which are available to keep such kind of organisms physiologically active in extremely dark, hot, acidic or alkalic and high-pressure areas of our home planet. These findings will have implications for the search for life on other planets and moons such as Mars, the Jovian moon Europa or the Saturnian moon Enceladus.

Streaming link:


You can view the lecture via the following link at Youtube:

https://www.youtube.com/watch?v=GPlZtiq19Ws

EAI on-line seminar: CLIMATE BISTABILITY OF TERRESTRIAL EXOPLANETS 

Julie Noivaková, Charles University Prague; Czech Republic

20 October 2020, 16:00 CEST (14:00 UTC)


From medieval Japanese folk tales to modern science fiction, people have always imagined whether there could be life outside of the Earth. But only recent decades brought us the means to "go where no one has gone before" and test it. How has older and contemporary fiction imagined life on Venus, Mars, Europa or in other star systems entirely, and what can current science say about that?

Author, biologist and educator Julie Nekola Nováková will lead us on this journey through space and time and show the way science fiction can help us understand and communicate science, such as in the e-book anthology Strangest of All, edited for the European Astrobiology Institute.


The seminar can be watched on Youtube here:

https://www.youtube.com/watch?v=uTjHdr9ND08


EAI on-line seminar: CLIMATE BISTABILITY OF TERRESTRIAL EXOPLANETS 

Antonello Provenzale, CNR, Italy

22 September 16:00 CEST (14:00 UTC)


Planetary climates are complex systems that include a multitude of stabilizing (negative) and destabilizing (positive) feedback loops. One of them, the ice-albedo feedback, is thought to be responsible for the existence of multiple stable states of the Earth’s climate, with the alternation between ice-covered conditions (the most extreme being the so-called Snowball) and warm states. Here, we explore the possible presence of bistability in the climate of Earth-like planets, using a simple one-dimensional climate model called ESTM. During the talk, we will consider the role of ice-albedo feedback for a wide range of orbital and planetary parameters such as distance from the star, ellipticity, obliquity and atmospheric pressure. Other possible mechanisms for bistability will also be mentioned, such as the vegetation-albedo and the vegetation-moisture feedbacks. Implications on planetary habitability will finally be discussed. The recording of the seminar is available at Youtube here.


This will be the first seminar in a series of EAI on-line seminars. To join follow the following link:

https://www.gotomeet.me/europeanastrobiologyinstitute/eai-webtalk1