The Music of Cosmic Rays

Cosmic rays continuously collide with the Earth and Moon, whirled into isotropy by galactic magnetic fields between here and their origin at distant high‐energy cosmic events such as collapsing stars and jetting black holes. Every cosmic ray is like a note or a written chord, which, when struck, sings a complex, ringing harmonic. When an ultrahigh-energy cosmic ray enters a solid, particulate material such as regolith or the atmosphere, it produces a relativistic cascade of secondary charged particles and an intense, coherent, wideband, linearly polarized electromagnetic pulse via the Askaryan Effect. This electromagnetic pulse is physically analogous to a sonic boom. Each electromagnetic pulse propagates through and is reflected and refracted by subsurface geophysical structures. Thus, cosmic rays serve as a pervasive, natural, non-destructive electromagnetic source for planetary subsurface geophysical sensing.

That is, cosmic noise can be interpreted. With the right ear, the noise is interpretable, decipherable music, which communicates a story about something that would, without art, remain too abstract or obscure to understand. Here, I present an overview of a novel planetary remote sensing and in-situ measurement approach that listens for the electromagnetic music made by cosmic rays via the Askaryan Effect and their detectable, interpretable radio signals, drawing on the fundamental connection to sound and music to communicate this beautiful and abstract physics.

This presentation is supported by the NASA Early Career Award in Planetary Science (80NSSC24K1214).