A symmetrical tear in time that opens up an alternate history when it takes the U.S.S. Enterprise NCC-1701-C from its mercy sacrifice against Romulans at an attacked Klingon outpost, Narendra III. The resulting war-weary United Federation of Planets alternate history is blinked out without a memory when the old ship returns to its intended fate, repairing the damage. The swirling circular rift showed gravimetric fluctuations unlike Data had ever seen: no event horizon, center or outer edge, or coordinates. He theorized it might be a Kerr loop of superstring material and highly unstable, formed from high-energy interaction in the original battle vicinity such as exploding photon torpedoes.