Events at Physics
discuss the physics and implications of momentum injection via
radiation pressure on dust grains and supernovae, including
predictions for the galaxy-scale winds driven by rapidly star-forming galaxies and the characteristic surface density of star formation in ultra-luminous infrared galaxies. I discuss the disruption of giant molecular clouds, with implications for their star formation efficiency. I also present constraints on the magnetic field and cosmic ray energy densities in starbursts derived from the far-infrared--radio correlation and the gamma-ray emission of the local starbursts M82 and NGC 253.