The Universe is permeated by hot, turbulent magnetized plasmas where particles are heated and accelerated as a result of energy dissipation in turbulent environments. It is of key importance to study and understand how plasma is energized by turbulence for the comprehension of fundamental physical processes ubiquitous in the Universe. The Turbulent Heating ObserveR (THOR) is a space mission that has been selected has a candidate for the ESA’s next M4 mission within the Cosmic Vision program. THOR is the first mission dedicated to the study of the turbulent energy dissipation and particle energization in space plasmas. In fact, with unprecedented high time resolution and high accuracy particle and fields in situ measurements, complemented with sophisticated numerical simulations, it aims to unveil plasma physics at kinetic scales, where most of the energy dissipation occurs. Here we present THOR science objectives in the framework of the physics of the plasma Universe.