Each beat of Captain’s twin hearts took half a day in the universe outside. When the Sumerians came down from their mountains to invent the city on the Persian plateau, Captain was invited to participate in the forthcoming anniversary talk. As he prepared his guest list, Sargon built an empire. While he instructed his machines with the program for the meeting small, shivering men hewed blue stone into menhirs to form Stonehenge. Columbus discovered America while Captain was fretful over last-minute cancellations and changes; he finished his evening meal while the first human rockets tottered into orbit and decided to stretch his legs before retiring as a human explorer, wild with surprise, broke into the first Heechee tunnel on Venus. He slept through the time of Robin Broadhead’s growth, puberty, voyage to Gateway and voyages from it, the discovery of the Food Factory, the decision to explore it. He half woke just as the Herter-Hall party was starting its four-year climb to orbit, and went back to sleep-to him it was the equivalent of less than an hour-through all their wearying trip. Captain, after all that, was still relatively young. He had the equivalent of a good ten years of active, energetic life ahead of him-or what the outside universe would see as a quarter of a million years.
From "Beyond the blue event horizon" by Frederik Pohl
From the chapter "The place where the Heechee went".