I am an expert in stellar dynamics and I work on several aspects of the formation and evolution of dense stellar clusters in the Galaxy and I explored issues related to the formation of the solar system. The tools I use are GPU-accelerated direct N-body codes and dynamical models that I develop and analyse such to compare them directly to observations. I used my own GPU-parallelised direct N-body code (NBSymple) and other codes to study the evolution of globular clusters (GCs) in the Galactic potential, and the origin of their tidal tails. I investigated the chemical anomalies in GCs finding key observational predictions to test multiple populations formation scenarios. I proved that GC internal metallicity spreads can be the result of mergers between disc clusters. I numerically followed the inspiral of GCs to the Galactic centre showing how they significantly contribute to the formation of the central nuclear star cluster. On planetary scales, I solved the long-standing Earth-Moon composition similarity issue.