Once Before Time - Martin Bojowald [124]
But it is much more likely that such an inversion of time’s arrow would merely represent an illusion of the chosen mathematical description. As one wanders on Earth along a track across the North Pole, the latitude first motions upward. Once we pass the pole, the latitude decreases, but that does not mean that one would now travel back along the old trail. The longitude, after all, takes a different value on the other side of the pole. In the same way, the turning point of the volume of the universe, when used as a parameter for time during the collapse, would not mean that time then runs backward. Analogously to the longitude, one would just have to use other parameters to keep separate the universe before and after its maximal extension. Quantum cosmology thus does not offer clear-cut reasons for the reversion of time either.
All scenarios of doom had, as always, turned out to be false prophecies. True, the universal economy had nearly collapsed, but this prediction, given all the panic-mongering, was self-fulfilling. Long ago, the background radiation of gravitational waves had been measured out so sensitively that the composition of the universe was known precisely enough to compute its future. After the acceleration caused by the transient dark energy had ceased, the expansion itself began to slow down and was now on the verge of stopping, setting the whole universe on a collapsing path. The exact time for the expansion’s end was not known, but every estimate resulted in a value within several decades. At first it did not appear threatening, for it would take further trillions of years for the universe to become too dense and hot for survival. On the contrary, a return to a warmer universe appeared tremendously welcome.
And yet, voices that raised this turning point of expansion to the status of the end of the world grew louder. Despite all the successes of stoop theory, one question had remained unanswered: What exactly is time, and is its progress reversible or perhaps tied to the development of the universe? Old theories had related the direction of time to the expansion of the universe, even postulating a redirection of time’s arrow in a collapsing universe. One would then remember the future and predict the past. This expectation was founded on some forms of quantum cosmology whose implications in such a big universe, as it was constituted then, were normally minute; all other progress notwithstanding, such theories thus remained poorly tested. Now people vaguely recalled the distant possibility of the reversion of the arrow of time—an idea that, most likely thanks to its esoteric character, spread fast.
Under those circumstances, it did indeed appear reasonable to squander all one’s savings (at least within the limits allowed by the life processes, artificially slowed down for survival in a cold, empty universe). If the direction of time will soon revert, savings, interest, investments, and funds lose their meaning. Instead, one should spend all one’s money and live life to the fullest, a luxury to be revisited after time’s reversion. Many followed this principle in expectation of the collapse. Large consumer spending led to an economic boom never seen before. But when at last the expansion of the universe stopped and collapse ensued, no reversion of time’s arrow occurred! The only cosmological consequence was that the universe now grew, slowly but unstoppably, warmer and ever denser—fuller: The stream of time was swelling …
8. COSMOGONY
MYTHS AND METHODOLOGY
It is not how things are in the world that is mystical, but that it exists.
—LUDWIG WITTGENSTEIN, Tractatus logico-philosophicus
The economy now was knocked to its knees; society was in disarray, for all resources lay in the hands of the few who had resisted the call to squandering. The civilizations