Understanding the physics that governs the star and planet formation process is one of the major challenges of modern astrophysics. These are key processes that govern the cycling of diffuse matter into stars and the formation of planetary systems. The key difficulties that we face as observational astrophysicists are that we are not able to run controlled experiments. We do observe the possible initial conditions, the processes at work, and their final outcome, but not as a well defined sequential experiment, as, in most cases, we can only make educated guesses on the past history and future outcome of any object we observe.
Leonardo will present two approaches that can be followed to understand the underlying physics in the star and plant formation process: simplified modeling of large samples of objects, to identify the main physical properties, and the comparison of detailed numerical simulations with observed objects. This latter approach offer the possibility of running controlled (numerical) experiments, but the challenge is to compare these with real observations.