In recent decades, particle physics has made significant advances in our understanding of high-energy phenomena, both on theoretical and experimental fronts, culminating in the current Standard Model (SM) of particle physics. However, the SM is not a self-contained theory and leaves many questions unanswered; in particular, it falls short of incorporating dark matter or gravitational forces. Among the implications for this is that, beyond the quantum gravity scale, we expect the SM to be replaced with a more fundamental theory giving a quantum description of gravity. As such, effective theories that arise from this fundamental theory can break certain symmetries that normally hold in the SM, such as Lorentz- and CPT-invariance . As a result of this, we expect there to be observables that exhibit low-energy manifestations of these symmetry violations, and in turn, this could have implications for neutrinos and other astrophysical messengers. In this talk, I give an overview of work that I have done in theory, phenomenology, and experimental high-energy physics in the area of effective theories of high-energy phenomena. In an effort to characterize the astrophysical neutrinos that IceCube has observed, I discuss what we can learn about the physics that happens between the production of astrophysical particles and their subsequent detection.