PROTON PAIRS EJECTED FROM NUCLEI help to reveal the nature of the strong interaction. The force that holds atoms together, the electromagnetic interaction between electrons and the nucleus, is much better understood than the force that holds together the nucleus itself, namely the strong interaction among the constituent protons and neutrons. Physicists can't directly reach inside the nucleus with a force meter, but they can dislodge some of the nuclear masonry and examine the fragments as would an archeologist looking at shards of pottery from a sunken vessel. At the National Institute for Subatomic Physics (NIKHEF in Dutch) in Amsterdam, a beam of electrons strikes oxygen nuclei, knocking out pairs of protons. For just the right collision energy, the protons (which are detected in coincidence with the scattered electron) emerge primarily in a special state (an S state), one in which their relative angular momentum is zero. Such protons would have been very close (less than 10^-15 m apart) to each other in the nucleus just before being struck by the electron. The NIKHEF experiment, the first to compile cleanly such ejected S-state proton pairs, can thus probe very short range correlations between two particles inside the nucleus. (C.J.G. Onderwater et al., , Physical Review Letters, 30 June 1997 contact Willem Hesselink, whah@nikhef.nl.)