Homoquiralidade: raios cósmicos podem ter deixado marcas indeléveis no início da vida

quinta-feira, maio 21, 2020

The Chiral Puzzle of Life
Noemie Globus1,2 and Roger D. Blandford3

Published 2020 May 20 • © 2020. The American Astronomical Society. All rights reserved.
The Astrophysical Journal Letters, Volume 895, Number 1

Published 2020 May 20 • © 2020. The American Astronomical Society. All rights reserved.

Author e-mails



Author affiliations

1 Center for Cosmology & Particle Physics, New York University, New York, NY 10003, USA

2 Center for Computational Astrophysics, Flatiron Institute, Simons Foundation, New York, NY 10003, USA

3 Kavli Institute for Particle Astrophysics & Cosmology, Stanford University, Stanford, CA 94305, USA

Received 2020 March 4, Accepted 2020 April 27, Published 2020 May 20

Citation Noemie Globus and Roger D. Blandford 2020 ApJL 895 L11

Keywords Astrobiology ; Cosmic rays


Biological molecules chose one of two structurally chiral systems which are related by reflection in a mirror. It is proposed that this choice was made, causally, by cosmic rays, which are known to play a major role in mutagenesis. It is shown that magnetically polarized cosmic rays that dominate at ground level today can impose a small, but persistent, chiral bias in the rate at which they induce structural changes in simple, chiral monomers that are the building blocks of biopolymers. A much larger effect should be present with helical biopolymers, in particular, those that may have been the progenitors of ribonucleic acid and deoxyribonucleic acid. It is shown that the interaction can be both electrostatic, just involving the molecular electric field, and electromagnetic, also involving a magnetic field. It is argued that this bias can lead to the emergence of a single, chiral life form over an evolutionary timescale. If this mechanism dominates, then the handedness of living systems should be universal. Experiments are proposed to assess the efficacy of this process.