This book summarizes recent developments in the research area of quantum gravity phenomenology. A series of short and nontechnical essays lays out the prospects of various experimental possibilities and their current status. Finding observational evidence for the quantization of space-time was long thought impossible. In the last decade however, new experimental design and technological advances have changed the research landscape and opened new perspectives on quantum gravity. Formerly dominated by purely theoretical constructions, quantum gravity now has a lively phenomenology to offer. From high precision measurements using macroscopic quantum oscillators to new analysis methods of the cosmic microwave background, no stone is being left unturned in the experimental search for quantum gravity. This book sheds new light on the connection of astroparticle physics with the quantum gravity problem. Gravitational waves and their detection are covered. It illustrates findings from the interconnection between general relativity, black holes and Planck stars. Finally, the return on investment in quantum-gravitation research is illuminated. The book is intended for graduate students and researchers entering the field.

Preface (S. Hossenfelder).- Astroparticle physics connections to the quantum gravity problem (M. Lorenz).- The search for a tiny hint from quantum gravity in the cosmic relic radiation (D. Brizuela, M. Kraemer).- Superfluid Helium: the Volovik Lessons (T. Lappe).- On the Paradigms of Quantum Gravity 2016 (F. Mueller).- On the Measurement of the Speed of Light in a Cavity (F. Schneiter).- Neutrino: the elusive particle bringing us closer to the world of quantum gravity (G. D'Amico).- Gravitational Waves: The “Sound” Of The Universe (J. M. Carmona).- Planck Star Phenomenology (A. M. Eller).- Gravitational measurements at small distances (H. Schmidt).- Return on investment in quantum-gravity research (G. Amelino-Camelia).- Semiclassical Gravity: A testable theory of Quantum Gravity (S. Scully).- Quantum gravity deformations (A. M. Frassino).- General Relativity, Black Holes and Planck Stars (M. Trudu).- Spacetime Structure: Analogy in Condensed Matter & Quantum Information (M. Seltmann).-Experimental Search for Quantum Gravity using Cosmology (M. Bischoff).- The Cosmological Constant and its Problems: A Review of Gravitational Aether (M. F. Wondrak).