Exploring the Universe at the Highest Energies: when Particle Physics and Astronomy meet

High-energy neutrinos propagating over cosmological distances are the ideal messenger particles for astrophysical phenomena, but the neutrino landscape above 10 PeV is still mostly unexplored. At these extreme energies, neutrinos can image the most extreme objects in remote corners of our cosmos and help access fundamental physics at extremely short distances.In this talk, I will show how we are presently constructing the Radio Neutrino Observatory in Greenland, the largest-ever terrestrial neutrino detector, and how the century-old physics of electrodynamics plays a central role in its operation. Combining ideas from particle collider instrumentation with high-performance computing, we will see what it takes to fully exploit the science potential of this unique instrument and thereby extend neutrino astronomy into the regime of the exaelectronvolt.