Probing universal ISM processes with SOFIA

Given the topic of this IAU Symposium, it is appropriate to ask the question which are the universal processes related to gas in galaxies and how our telescopes (here SOFIA) contribute to address our understanding of these fundamental processes. The dynamical processes include heating and cooling (warm and cold gas), collapse and outflows, formation and destruction of molecular clouds (shocks and rad. feedback). Not to mention turbulence and the interaction of interstellar gas with magnetic fields. SOFIA is a primarily spectroscopic machine to uniquely study these processes in our Milky Way and in a few neighboring spiral and irregular galaxies. SOFIA's spectroscopic observations of the Milky Way and nearby galaxies will be key to understand the physical processes in general and necessary in order to extrapolate to observations of distant, star forming galaxies where none of the details of these processes can be spatially resolved. This is why local SOFIA observations will be critical for our understanding of high-z, gas-rich galaxies. In this contribution, we will illustrate how SOFIA can be of major importance to study key interstellar processes (as opposed to gas parameters).