Final answer:
The Univac gained world prominence when it accurately predicted the outcome of the 1952 U.S. presidential election on national television.
Step-by-step explanation:
The single event that propelled the Univac to world prominence was its use during the 1952 U.S. presidential election, where it predicted the outcome of the election with remarkable accuracy on national television. This event captured the public's imagination and demonstrated the machine's capabilities to a wide audience, solidifying its status as a landmark in computing technology.