Through a natural force of coherence, life adapts to its environment to enhance survival. This evolutionary impetus starts at the molecular level.
Cosmic rays are high-speed particles – atomic nuclei, mostly protons, and a smattering of electrons – hurled by stellar bodies. The term ray is a historical misnomer, as the emissions were originally thought – wrongly – to be electromagnetic radiation.
Upon encountering Earth’s atmosphere, cosmic rays eventually degrade into fundamental particles. Near the surface, most cosmic rays are reduced to muons: unstable elemental particles which last for a mere 2 millionths of a second, albeit traveling near the speed of light.
Magnetization, aka magnetic polarization, is a decided spin (vector field) in any particle subject to electromagnetism – which includes all bits of matter. Magnetization is not necessarily uniform within a material but may vary between different points.
Muons are magnetized. All muons have the same magnetic orientation. When muons give up the ghost, they produce electrons with the same magnetic polarization.
“We are irradiated all the time by cosmic rays,” explained astrophysicist Noémie Globus. “Their effects are small but constant every place on the planet where life could evolve, and the magnetic polarization of muons and electrons is always the same.”
Chirality, also known as handedness, is an identifiable discrepancy (asymmetry) between an object and its mirror image. The human hand is the classic example of chirality.
All biological molecules are chiral. Chirality “was causally made by cosmic rays,” propose Globus and fellow astrophysicist Roger Blandford.
RNA and DNA, which are the molecular correlates of bioproduction information, are composed of nucleotides: linear sequences of building blocks with the same handedness. “The chirality of nucleotides confers helical structure on nucleic acids,” explained Globus and Blandford. “As RNA and DNA are made of D-sugars (right-handed, by human convention), the more stable conformation is a right-handed helix. The homochirality of the sugars has important consequences for the stability of the helix and, hence, on the fidelity or error control of the genetic code. All 20 encoded amino acids are left-handed (again by human convention).”
Microbiologist Louis Pasteur discovered biological homochirality in 1848. He recognized it as a consequence of some asymmetry in the laws of Nature: “If the foundation of life is dissymmetric because of dissymmetric cosmic forces operating at its origin, this is one of the links between life on earth and the cosmos.”
Physicist Pierre Curie wrote of chirality transfer from light to molecules in 1894. “The sense of rotation of the polarization direction reflects the underlying chirality of the molecules, though the relationship is not simple and depends upon the wavelength of the light (optical rotatory dispersion),” note Globus and Blandford.
Globus and Blandford conclude: “Homochirality is a deterministic consequence of the weak (nuclear) interaction, expressed by cosmic irradiation of helical biopolymers which may have affected the way they fold or assemble to make the first living organisms. This is a consequence of the coupling that can lead to symmetry-breaking, as anticipated by Pasteur. The choice that was made is then traceable to the preponderance of baryons over antibaryons, established in the early universe and ultimately to the symmetries of fundamental particle interactions presenting requirements (including leptonic charge parity violation) as first elucidated by (nuclear physicist Andrei) Sakharov in 1967.”
Biological chirality is a consequence of a decided cosmic orientation that pervades the very expression of existence.
Noémie Globus & Roger Blandford, “The chiral puzzle of life,” The Astrophysical Journal Letters (20 May 2020).
” How cosmic rays may have shaped life,” ScienceDaily (20 May 2020).