Studying at York
Astrobiology - PHY00061I
- Department: Physics
- Module co-ordinator: Dr. Emily Brunsden
- Credit value: 20 credits
- Credit level: I
- Academic year of delivery: 2024-25
Module summary
Astrobiology is the study of life in the Universe. This module examines what life we are searching for based on our understanding of the evolution of life of Earth, the key tools and techniques we use and the priority locations we may expect life to be beyond our planet. The module will cover the fundamentals of planet formation and evolution, as well as exploring the chemical and physical environments within our own solar system. We will examine the conditions that allowed life to develop on Earth and the variety and requirements of life that exists, even in extreme environments. We use this to identify other bodies in our own Solar System that may host the right conditions for primitive life as well as the potential biosignatures through which this life may be recognized.
Key concepts in planetary and exo-planetary science will be examined, with a focus on detection methods and determining planetary characteristics as well as techniques used to assess the capability of exoplanets to sustain life. The probability that intelligent life exists elsewhere in the Universe will be discussed within the context of the scientific method.
Related modules
Pre-requisites: Completion of Stage 1 in a Physics, Biology, Environment programme or with Module Coordinator approval.
Module will run
| Occurrence | Teaching period |
|---|---|
| A | Semester 2 2024-25 |
Module aims
This interdisciplinary module aims to bridge the disciplines of physics, astrophysics, biology and chemistry to understand the study and search for life in the Universe. It will bring together students from these disciplines and from other programmes in the Faculty of Science to bring their own knowledge and understanding from their discipline and to learn more from others.
Module learning outcomes
Subject Content
- Demonstrate an understanding of the chemical, astrophysical and biological conditions which existed such that life developed on Earth.
- Identify the likely environments in the current day solar system that provide the potential to develop life demonstrating an understanding of key biological processes.
- Identify and evaluate biological outputs that may be used as biomarkers/biosignatures and the astrophysical techniques used to search for them in the solar system and beyond.
- Contextualise current research and scientific debates within planetary, exoplanetary and astrobiological sciences including philosophical discussions pertaining to life beyond Earth.
Academic and graduate skills
- Absorb, organise and synthesise information from different disciplines to discuss and write coherently on questions in astrobiology, supporting arguments with relevant information facts and ideas.
- Construct coherent arguments and discussions of broad questions in astrobiology supported by facts, theories, and speculation and appreciate their differences.
- Communicate information and ideas to an appropriate standard and in such a way as to enable understanding and engagement by an academic, non-specialist audience.
Module content
Syllabus
Are we alone?
An introduction to the Drake equation, the Fermi Paradox and the Rare Earth Hypothesis to
frame the content of the module.
(S) Seminar: Life in the Universe
How to build a solar system
An overview of solar-system science. The key concepts of the structure and evolution of our own solar system will frame a discussion of current environments we observe. How did our solar system form? Why are the planets where they are? What are their interior and exterior features? What are their sources of energy?
- You are Here: An inventory of the Solar System, Kepler’s Laws
- How to Build a Solar System: From molecular cloud to planets
- Our Cosmic Backyard I: Interiors and Surfaces
- Our Cosmic Backyard II: Magnetic Fields and Atmospheres
- Sources of planetary free energy
- Goldilocks planets. Goldilocks moons.
(S) Seminar: Literature review - Unanswered questions about the Solar System
Life, its beginning on Earth and today
What is life, how is it defined, and what are its known origins on Earth? This section will look at the physical/chemical processes necessary for life to have arisen on Earth. What elements are needed to create membranes and/or replicating molecules? How did these basic building blocks assemble into the first cells? What energy resources were the first cells
able to access/utilise? Explore the redox ladder of energy resources and how this provides opportunities throughout the Earth system (with pointers to other planets). What organisms are able to access these resources, what environments are they able to tolerate (including tested extraterrestrial environments)? Understanding the faint young Sun paradox, and the evolution
of the atmosphere will be explored.
Following on from the evolution of the Earth’s atmosphere an exploration of biosignatures/biomarkers as generated by specific environment types/organisms.
- Starting life requirements
- Development of more complex life
- Earth evolution, as driven by life
- Redox biochemistry and available energy resources
- Extremophiles/extreme environments on Earth
- Biosignatures arising from local and regional environment and resources.
(S) Seminar: Places for potential life in the Solar System
Exoplanets
We will look at observational evidence from exoplanetary systems and how they are characterised. What are the categories of exoplanets, and how do we determine their physical characteristics?
We will look at results from Kepler and other missions. An overview of detection techniques, with focus on Radial Velocity and Transit measurements. Properties of the planets, selection effects and biases in the methods will be discussed. The concept of habitable zones within solar systems will be explored as well as the idea of galactic habitable zones. Concepts such as binarity, tidal locking and exo-moons will be explored, as well as current and future work from the space telescopes JWST and TESS.
We will discuss the current search for biomarkers and modern results from transmission and reflection spectroscopy
- How to find an exoplanet: Radial Velocity and Transit Techniques
- Characterising Exoplanets: Calculating Radius, Mass, Density and Temperature
- Exoplanet Populations and Statistics
- Breaking the Rules: Extreme exoplanets and their impacts on understanding planet
- formation and migration
- Biosignature Detection: Current Techniques and progress
(S) Seminar: Exoplanet Case Studies
Are we (still) alone?
A return to the Drake equation, the Fermi Paradox and the Rare Earth Hypothesis using the understanding developed in the module. Our place in the wider universe will be discussed and the physical limitations of interstellar travel will be explored. We discuss the science of SETI and other searches for life and close with a summary of the module.
(S) Seminar: Life in the Universe Revisited
Indicative assessment
| Task | Length | % of module mark |
|---|---|---|
| Essay/coursework Small Structured Written Assessment on a Solar System Environment as a host for life |
N/A | 25 |
| Essay/coursework Structured Written Assessment on an exoplanet as a host for life |
N/A | 75 |
Special assessment rules
None
Additional assessment information
Reassessment Tasks are required to be on a different system to the original submission
Indicative reassessment
| Task | Length | % of module mark |
|---|---|---|
| Essay/coursework Small Structured Written Assessment on a Solar System Environment as a host for life |
N/A | 25 |
| Essay/coursework Structured Written Assessment on an exoplanet as a host for life |
N/A | 75 |
Module feedback
'Feedback’ at a university level can be understood as any part of the learning process which is designed to guide your progress through your degree programme. We aim to help you reflect on your own learning and help you feel more clear about your progress through clarifying what is expected of you in both formative and summative assessments.
A comprehensive guide to feedback and to forms of feedback is available in the Guide to Assessment Standards, Marking and Feedback. This can be found at:
https://www.york.ac.uk/students/studying/assessment-and-examination/guide-to-assessment/
The School of Physics, Engineering & Technology aims to provide some form of feedback on all formative and summative assessments that are carried out during the degree programme. In general, feedback on any written work/assignments undertaken will be sufficient so as to indicate the nature of the changes needed in order to improve the work. Students are provided with their examination results within 25 working days of the end of any given examination period. The School will also endeavour to return all coursework feedback within 25 working days of the submission deadline. The School would normally expect to adhere to the times given, however, it is possible that exceptional circumstances may delay feedback. The School will endeavour to keep such delays to a minimum. Please note that any marks released are subject to ratification by the Board of Examiners and Senate. Meetings at the start/end of each semester provide you with an opportunity to discuss and reflect with your supervisor on your overall performance to date.
Our policy on how you receive feedback for formative and summative purposes is contained in our Physics at York Taught Student Handbook.
Indicative reading
Lissauer, de Pater: “Fundamental Planetary Science”, Cambridge University Press, 2013
Kay, Palen, Blementhal: “21st Century Astronomy” 5th edition, W.W. Norton and Co., 2016
Rothery, Gilmour, Sephton, "An Introduction to Astrobiology" 3d edition, Cambridge University Press, 2018
Rothery, Gilmour, Sephton, "An Introduction to the Solar System" 3d edition, Cambridge University Press, 2018
C.A.Scharf, “Extrasolar Planets & Astrobiology”, University Science Books, Schwieterman et al. (2018).
Exoplanet Biosignatures: A Review of Remotely Detectable Signs of
Life. Astrobiology, 18(6): 663-708
Jelen et al. (2016) The role of microbial electron transfer in the coevolution of the biosphere and
geosphere. Annual review of microbiology 70: 45-62