The Chiral Puzzle of Life

Understanding the origin of life surely qualifies as one of the deepest and most perplexing questions facing humankind. While we have not yet reached a consensus on the definition of life, biological homochirality seems to be part of the definition as a necessary step for life's emergence. The unraveling of its origin require interdisciplinary research, by exploring each of fundamental physics, modern chemistry, astrophysics and biology. In this talk, We will focus on the origin of biological homochirality in the context of astrophysics and particle physics. The weak force, one of the fundamental forces operating in nature, is parity-violating, and has been implicated in biological homochirality since over half a century. Cosmic rays, high energy particles coming from outer space, induce showers of billions of secondary particles when they interact with atoms in the atmosphere. On Earth, at ground level, most of our cosmic radiation dose comes from polarized muons formed in a decay involving the weak force. We will show how the spin-polarization is transmitted in cosmic showers in different environments, how it can induce a chiral preference in the early biological life forms and we will discuss the implications for the search of life in other worlds.