Philosophical Issues in Astrobiology and Space Science Seminar Series 2024

Prof Christophe Malaterre

Université du Québec à Montréal

SPEAKER ONLINE

29th January 2024 (3:45pm GMT)

Beyond Historical Constraints: Dimensions of Inquiry into the Origin of Life

The question of the origin of life is a complex and persistent scientific inquiry involving a diversity of disciplinary perspectives. Prebiotic chemistry and micropaleontology approach it by explaining life's emergence in Earth's distant past, while systems chemistry and synthetic biology aim to demonstrate the synthesis of living matter independent of historical constraints. This contribution disentangles varied interpretations of the origin-of-life question, identifying three key dimensions—historical adequacy, natural spontaneity, and similarity to known life. We argue that the epistemic status of the explanandum shifts from nearly certain under stringent constraints to entirely speculative with relaxed constraints, transforming the question from an explanation-seeking inquiry to a fact-establishing exploration. We also examine how answers to specific interpretations of the origin-of-life question impact alternative interpretations.

Dr Margarida Hermida

King's College London

SPEAKER IN PERSON

26th February 2024 (3:45pm GMT)

Universal biological kinds and classification 

The main system of classification in biology – phylogenetic systematics – is genealogical. It places organisms within a web that reconstructs their relationships of ancestry and descent. Since all organisms on Earth have a common ancestor, they can all be placed on the same phylogenetic tree, but this would not be the case for extra-terrestrial life of independent origin, which would form its own separate ‘tree of life’. Astrobiology thus suggests the need for a universal biological classification. 

Despite the lack of consensus on a definition of life, certain requirements are expected to hold true of living things anywhere in the universe, due to physical constraints on what is possible. At the very least, all living things are material entities that extract free energy from the environment to maintain their own physical structure, avoid thermodynamic equilibrium, and carry out activities. A source of energy is indispensable for life. 

Mode of energy acquisition is therefore a good basis for a universal biological classification. For example, phototrophic organisms are those that obtain energy from light. Although photosynthesis evolved on Earth only once, it is no less likely to evolve on other planets, given certain prerequisites. All phototrophic organisms in the universe, regardless of origin, form a universal natural kind, which is likely to ground interesting generalisations. The use of atmospheric oxygen and photopigments as potential biosignatures suggests that the putative universal kind ‘phototroph’ is already in use in astrobiology. 

Due to the universality of physical laws, and the limited number of ways in which free energy can be harvested from the environment, a metabolic classification of organisms is well placed to uncover universal generalisations that apply beyond Earth, bringing biology closer to other sciences such as physics and chemistry, and facilitating novel prediction.

Pauli E. Laine

SPEAKER ONLINE

11th March 2024 (3:45pm GMT)

Should we seed life on exoplanets?

Claudius Gros, a theoretical physicist from the Institute for Theoretical Physics at Goethe University, Frankfurt, proposed an idea how robotic missions equipped with cryogenic pods with genes could be used to distribute microbial life to planets capable of supporting life, but not likely to give rise to it on their own. In this presentation, I talk about why we should or should not do something like this, i.e. could life on Earth be ultimately saved with directed panspermia, or should we do everything to prevent this from happening?

Professor Amaury Triaud MPhys, PhD, FRAS

SPEAKER IN PERSON

18th March 2024

(3.45pm GMT)

Temperate planets unlike those of the Solar system

For long, the Solar system was considered a template for planet formation, and Earth a template for habitability in the Cosmos. Recent exoplanet discoveries challenge that view. My team at Birmingham is investigating the outcome of planet formation in non Sun-like settings. We photometrically target the smallest stars of our galaxy with the SPECULOOS network to seek Earth-like planets, and confirm long-period gas-giant & Neptune candidates with the ASTEP telescope in Antarctica. Meanwhile, we search and find circumbinary planets. Despite their architectural diversity, all these systems share a commonality, planets with temperate environments. Together they will test the limits of habitability, and provide an opportunity to measure the frequency of biology in the universe. I will complement my talk with a description of a new empirical signature for liquid water, which can also be used as a biosignature.