Scientists have found a new way to 'see' inside the simplest atomic nuclei to better understand the 'glue' that holds the building blocks of matter together. The results come from collisions of photons (particles of light) with deuterons, the simplest atomic nuclei (made of just one proton bound to one neutron). The photons act somewhat like an x-ray beam to provide the first glimpse of how particles called gluons are arranged within the deuteron.