The radiation was being produced by a 31st century time travel pod, which Enterprise had discovered drifting in space. Examining the pod, Commander Charles Tucker and Lieutenant Malcolm Reed experienced the effects of the radiation firsthand, after removing a panel from the exterior of the pod. As they engaged in the same conversation over and over again, they soon began to realize what was happening. Upon examination by Doctor Phlox, they discovered that the particle density was too low to allow any lasting effects, but Captain Archer nevertheless ordered the launch bay sealed off.