“Role of Polarized Radiation in the Origin of Life: an Astrobiology Perspective”
Speaker: Dr. Noémie Globus, Assistant Professor at Instituto de Astronomía – Universidad Nacional Autónoma de México / Stanford
Date: Friday, April 18, 2025
Time: 3:30 – 4:30pm
Location: ISB 102 & Zoom (link)
Because it is so unique to life, the origin of biological homochirality has been an intense matter of research since its discovery by Pasteur in 1848. Some think homochirality was imprinted on early life via parity-violating mixing of the weak and electromagnetic interactions. If so, life’s specific handedness would be universal and deterministic. Others argue that it may be the result of chance: a random molecular accident during the pre-biotic phase that was amplified by cycles of enantioselective chemical reactions. In this talk, I will discuss the potential role of spin-polarized cosmic radiation in the development of life on Earth by potentially influencing the mutation rate of early life forms and even shaping the chirality of biological molecules. An initial chiral bias by spin-polarized cosmic radiation would be the basis for chiral life since it would be exponentially amplified by replication reactions of evolution. An experimental investigation is underway and will be described. I will also discuss how spin polarization is transmitted in cosmic-ray showers in different environments and the implications for the search for life in other worlds. I will finally show how a nearby supernova activity has the potential to raise the polarized radiation levels at the surface of the Earth by several orders of magnitude.
About the Speaker:
Noémie Globus was a Presidential Postdoctoral Fellow at UC Santa Cruz 
from 2021 to 2024. The question: What impact do cosmic rays have on life? Has haunted her for a long time and she conducts interdisciplinary research on the role of cosmic rays in the emergence and evolution of life, involving knowledge from different fields. While biologists have not yet reached a consensus on the definition of life, homochirality – the specific molecular handedness of biomolecules – is a phenomenon only produced by life. One of her research goals is to understand if spin-polarized cosmic radiation can act as a chiral evolutionary pressure.