The thematic cluster "Physics of the two infinities" gathers groups (from LLR, LPP and CPhT) interested in the infinitely small, as studied in theoretical and experimental particle physics and string theory, and the infinitely large, for example the study of interplanetary plasmas and non thermal effects in the universe. The connection between these apparently disparate domains is actually very strong, in both their conceptual and instrumental aspects. The researchers who also teach do so within the "Programme d'Approfondissement" (PA) in Physics, primarily in the course entitled "From particles to stars: fundamental interactions and elementary particles", and the PA Energy for the XXIst century.