Friendship and Relativity: “If Einstein succeeded in transforming time into space, Godel would perform a trick yet more magical: He would make time disappear. Having already rocked the mathematical world to its foundations with his incompleteness theorem, Godel now took aim at Einstein and relativity. Wasting no time, he announced in short order his discovery of new and unsuspected cosmological solutions to the field equations of general relativity, solutions in which time would undergo a shocking transformation. The mathematics, the physics, and the philosophy of Godel’s results were all new. In the possible worlds governed by these new cosmological solutions, the so-called ‘rotating’ or ‘Godel universes,’ it turned out that the space-time structure is so greatly warped or curved by the distribution of matter that there exist timelike, future-directed paths by which a spaceship, if it travels fast enough — and Godel worked out the precise speed and fuel requirements, omitting only the lunch menu — can penetrate into any region of the past, present, or future.

Godel, the union of Einstein and Kafka, had for the first time in human history proved, from the equations of relativity, that time travel was not a philosopher’s fantasy but a scientific possibility. Yet again he had somehow contrived, from within the very heart of mathematics, to drop a bomb into the laps of the philosophers. The fallout, however, from this mathematical bomb was even more perilous than that from the incompleteness theorem. Godel was quick to point out that if we can revisit the past, then it never really ‘passed.’ But a time that fails to ‘pass’ is no time at all.

Einstein saw at once that if Godel was right, he had not merely domesticated time: He had killed it. Time, ‘that mysterious and seemingly self-contradictory being,’ as Godel put it, ‘which, on the other hand, seems to form the basis of the world’s and our own existence,’ turned out in the end to be the world’s greatest illusion. In a word, if Einstein’s relativity theory was real, time itself was merely ideal. The father of relativity was shocked. Though he praised Godel for his great contribution to the theory of relativity, he was fully aware that time, that elusive prey, had once again slipped his net.

But now something truly amazing took place: nothing. Although in the immediate aftermath of Godel’s discoveries a few physicists bestirred themselves to refute him and, when this failed, tried to generalize and explore his results, this brief flurry of interest soon died down. Within a few years the deep footprints in intellectual history traced by Godel and Einstein in their long walks home had disappeared, dispersed by the harsh winds of fashion and philosophical prejudice. A conspiracy of silence descended on the Einstein-Godel friendship and its scientific consequences.” (Chronicle of Higher Education)