EAI on-line seminar: THE ORGANIC INVENTORY OF PLANET FORMATION 

Catherine Walsh, University of Leeds, UK

Tuesday, 9 February 2021, 16:00 CET (15:00 UTC)


Protoplanetary disks around young stars are the factories of planetary systems. These structures contain all the material - dust, gas, and ice - that will build planets and other bodies such as comets. Hence, understanding the physics and chemistry of disks provides much needed insight into the conditions under which planets form, and determining their molecular content reveals the raw ingredients of planetary atmospheres.

In this talk, I will show how state-of-the-art observations at (sub)mm wavelengths with ALMA (the Atacama Large Millimeter/submillimeter Array have revealed the composition of the planet building zone of protoplanetary disks. I will present early results from the first ALMA Large Program dedicated to the observation of molecular line emission from protoplanetary disks around nearby young stars at high angular resolution (0.1" - 0.3"), titled "Molecules with ALMA on Planet-Forming Scales" or MAPS. I will present images that reveal intriguing sub-structure in emergent line emission from key organic molecules. I will also discuss how observations in the gas-phase of large organic molecules provide insight into the composition of the icy-comet building reservoir around other stars.  Finally I will discuss how early results from MAPS have provided the most detailed studies to date of the chemistry of planet formation.

The lecture is available at at: EAI-Seminars Series: The Organic Inventory of Planet Formation - YouTube



EAI on-line seminar: EARLY TRACES OF THE THREE DOMAINS OF LIFE: EVIDENCE AND CHALLENGES  - NEW DATE

Emmanuelle Javaux, University of LIége, Belgium

Tuesday, 20 April 2021, 16:00 CEST (14:00 UTC)


Deciphering the early record and evolution of life is crucial to characterize plausible and reliable biosignatures of microbial life and understand the evolution of the Earth biosphere. We can then address questions regarding the conditions for life to appear and develop on a planetary body (habitability), or the probability for an extraterrestrial biosphere to develop complex metabolism or complex life. This research is also critical to develop life detection strategies, instruments and missions applicable to other planets of the solar system such as the ongoing and future Martian missions, and to atmospheres of rocky exoplanets, and to samples returned to Earth, as space agencies have recently come to appreciate.

Considerable debates still exist regarding the age and origins of the three domains of life (Archaea, Bacteria, Eucarya), as well as the evolution of cellular life before LUCA. Possible isotopic, biosedimentary, molecular and morphological traces of life suggest the presence of microbial communities in diverse environments. However, these traces may in some cases also be produced by abiotic processes or later contamination, leaving a controversy surrounding the earliest record of life on Earth. Before a microstructure can be accepted as a microfossil, a series of approaches need to be employed to prove its endogenicity, syngenicity, and biological origin, as well as to falsify an abiotic explanation for the observed morphologies or chemistries. These micro- to nano-scale analyses complement the macro-scale characterisation of the geological context, as the environmental conditions will determine the plausibility of ancient habitats and the conditions of fossilisation.  Experimental taphonomy also helps understanding the processes of decay and preservation of biosignatures during fossilization. Interpreting the identity and paleobiology of unambiguous traces may also be challenging. However, regardless of taxonomy, the paleobiological record can provide direct evidence for extinct clades and/or for the minimum age of evolution of biological innovations. Reassessing the evidence of early life is challenging but essential and timely for the quest of life’s first traces and evolution, both on Earth and beyond.


See the trailer at: https://www.youtube.com/watch?v=lrfZFlnKIEI&t=1s


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


EAI on-line seminar: IMPACT CRATERS AND LIFE (AND DEATH)  

Anna Losiak, University of Exeter, UK

Tuesday, 23 March 2021, 16:00 CET (15:00 UTC)


Impact craters form when rocky objects, such as asteroids or moons, collide with one another, especially when these objects are moving at exceptionally high speeds. This is a critically important process in the Solar System, because this process rapidly releases enormous amounts of energy, similar to the explosion of a bomb. This process can lead to many geological features, and on Earth, it has resulted in major changes to the environment. Ironically, impacts both endanger life, but also have created the environments necessary for the development of life, including the delivery of water to the planet. After impact craters form, they form warm enclaves where water is heated in hydrothermal systems, and generate niches for life, possibly including the origin of life itself. Without impact craters, we would not be here.


See the lecture here (on Youtube).


EAI on-line seminar: THE ORGANIC INVENTORY OF PLANET FORMATION 

David Dunér, Lund University, Sweden

Tuesday, 23 February 2021, 16:00 CET (15:00 UTC)


This seminar will deal with 4 iomportant questions in the search for signs of life in outer space:

 

  • How we form concepts of life in astrobiology, how we define and categorize things, and the relation between our concepts and our knowledge of the world:
  • How we see similarities between things, and with inductive, analogical reasoning go from what we know to what we do not know, from the only example of life here on Earth, to possible extraterrestrial
  • How we interpret what our senses convey in our search for biosignatures
  • How we, as interpreters, establish connections between things, between the expression (the biosignature) and the content (the living organism)

 In all, it is about how we get access to the world, and how we interpret and understand it, for achieving a well-grounded knowledge about the living Universe.

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The lecture can be seen at at: https://www.youtube.com/watch?v=pLEFaIIyj6g




EAI on-line seminar: TOWARDS MOLECULAR COMPLEXITY

Thomas Henning, Max Planck Institute for Astronomy, Germany

Tuesday, 26 January 2021, 16:00 CET (15:00 UTC)


Modern life is characterized by a complex DNA/protein machinery encapsulated in cellular systems. The talk will discuss how feedstock molecules such as hydrogen cyanide and formaldehyde can be produced
under early Earth conditions or in planet-forming environments. These molecules may then lead to RNA structures, amino acids and lipid
precursors.

 

The lecture is available at Youtube: https://www.youtube.com/watch?v=zZpP9C4Fe1w



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 is available at our YouTube channel: https://www.youtube.com/watch?v=ZzLbM1m7CNg



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:,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