Polarized Cosmic Rays and Astrobiology
Welcoming 2021 with a new submission.
As you read this, about one muon will cross your fingernail every second. Muons have interesting properties that could have played an important role in the emergence of life.
How? Muons are unstable particles with half-lives of a few microseconds. They are created by a decay involving the weak force, and they are spin-polarized on average. As we discussed last year, in ApJL 895 L11, this continuous spin-polarized cosmic radiation might explain the emergence of the particular handedness in life’s molecules. We don’t know yet how the effect is exactly translated in terms of influence on biological evolution (is it by muon capture or ionization?) but we are working on investigating it with biologists!
Where? For our model to work, muons needs to be the dominant component of secondary cosmic rays. Cosmic rays provide a free available source of muons everywhere but the "dominance" of the muonic component arises at different depths depending on the environment. In our new paper, we calculate spin polarized radiation doses at different prime target for the search of life in our solar system: Mars, Titan, Enceladus, Venus… Interestingly, Earth is the only body in the solar system where muons dominate the cosmic radiation at ground level. We discuss the biological implications and we hope to be able to perform experiments in the future!