Time Zero
Pity the hapless soul who comes face to face with a singularity, the nemesis of anyone trying to find a finite, well-defined solution to an equation. Einstein notably despised these mathematical beasts. In the 1930s and 1940s, while working with his assistants on various attempts to unify the various aspects of nature, he counseled that singularities were unnatural, even ungodly. Like a meticulous merchant wrapping up a precious package, he felt that an intelligent creator would not allow open ends. This cautionary note was passed down by Einstein’s assistants, such as Nathan Rosen, to their own students. For example, Fred Cooperstock, a student of Rosen’s, was used to such admonitions. Distaste for singularities has not faded over time. Today, despite the hard evidence of the background radiation, many researchers still find it hard to accept the idea that the universe was created in a state of infinite density and zero volume. How could it ever get out of such a state? Almost nobody doubts there was a period in the early universe when it was extremely hot and dense; in fact, WMAP and other measures of the cosmic microwave background provide unmistakable proof. There have been numerous other attempts to account for this radiation, but none of them can explain why its temperature is very nearly the same in all directions. Thus, for want of a better explanation most cosmologists accept that it is the remnant of a primeval fireball. The debate has to do with the Big Bang singularity itself. Could there be a way of accounting for all observed cosmological results without having the mathematics of the theory go haywire some 13.7 billion years in the past? Could the initial creation of matter be explained by a known physical process, rather than just by fiat? In the late 1960s, Hawking and Penrose demonstrated that just as black holes must have final singularities, the standard Big Bang must have had an initial singularity. The theorems they proved assumed that the universe contained material of typical density and pressure and that its dynamics could be modeled through ordinary general relativity. Most physicists have accepted these conditions as reasonable and have resigned themselves to a universe of indeterminate origin.
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| Evolution of the Universe |
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| Quantum fluctuations |
In recent decades, however, researchers have sought ways around this knotty issue. One such proposal was put forth, interestingly enough, by Hawking himself. At a 1981 conference organized by the Vatican, he suggested that space-time has no boundary. By substituting “imaginary time” (mathematically, real time multiplied by the square root of negative one) for real time, Hawking found that he could transform the Big Bang singularity into a smooth surface— akin to Earth’s South Pole. Just as Antarctic explorers don’t fall off the face of the Earth when they pass the pole, but rather change their direction from south to north, Hawking argued that if someone could travel back in imaginary time, past the Big Bang, they would simply start to move forward in time again. This is all well and good and shows a mathematical way of eschewing the initial glitch. However, to many physicists this explanation doesn’t seem physical enough, given that nobody can really travel in imaginary time. Other suggestions for eschewing the initial singularity have been based on quantum randomness. In 1973, Hunter College physicist Edward Tryon published a provocative article in the prestigious journal Nature, entitled “Is the Universe a Vacuum Fluctuation?” In quantum field theory, particles continuously pop in and out of the vacuum froth. Tryon pointed out that under extraordinarily rare circumstances a particle could randomly emerge from the foam with the mass of the universe. Though the chances of it coming forth at any given moment would be almost nil, it could literally take all the time in the world to make its debut. Eternity’s infinite patience would guarantee its emergence. This quantum fluctuation would serve as the creation event for the entire universe we see today.
Pity the hapless soul who comes face to face with a singularity, the nemesis of anyone trying to find a finite, well-defined solution to an equation. Einstein notably despised these mathematical beasts. In the 1930s and 1940s, while working with his assistants on various attempts to unify the various aspects of nature, he counseled that singularities were unnatural, even ungodly. Like a meticulous merchant wrapping up a precious package, he felt that an intelligent creator would not allow open ends. This cautionary note was passed down by Einstein’s assistants, such as Nathan Rosen, to their own students. For example, Fred Cooperstock, a student of Rosen’s, was used to such admonitions. Distaste for singularities has not faded over time. Today, despite the hard evidence of the background radiation, many researchers still find it hard to accept the idea that the universe was created in a state of infinite density and zero volume. How could it ever get out of such a state? Almost nobody doubts there was a period in the early universe when it was extremely hot and dense; in fact, WMAP and other measures of the cosmic microwave background provide unmistakable proof. There have been numerous other attempts to account for this radiation, but none of them can explain why its temperature is very nearly the same in all directions. Thus, for want of a better explanation most cosmologists accept that it is the remnant of a primeval fireball. The debate has to do with the Big Bang singularity itself. Could there be a way of accounting for all observed cosmological results without having the mathematics of the theory go haywire some 13.7 billion years in the past? Could the initial creation of matter be explained by a known physical process, rather than just by fiat? In the late 1960s, Hawking and Penrose demonstrated that just as black holes must have final singularities, the standard Big Bang must have had an initial singularity. The theorems they proved assumed that the universe contained material of typical density and pressure and that its dynamics could be modeled through ordinary general relativity. Most physicists have accepted these conditions as reasonable and have resigned themselves to a universe of indeterminate origin.
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