The following excerpts come from the April 2002 edition of
Discover magazine. The article is entitled
Guth's Grand Guess. Where did everything come from? Don't say, "the Big Bang." To say that everything came from the Big Bang is like saying babies come from maternity wards - true in a narrow sense, but it hardly goes back far enough. Where did the stuff that went "bang" come from? What was it? Why did it bang?
Before Alan Guth came along, cosmologists seldom dared to guess.
The Big Bang theory...said nothing about what came before or even during the split second when everything went bang. In December 1979 Guth, then 32 and an obscure physicist at the Stanford Linear Accelerator Center, emerged as the first scientist to offer a plausible description of the universe when it was less than one-hundredth of a second old. During an unimaginably explosive period between 10-37 second and 10-34 second after its birth, Guth said, the universe expanded at a rate that kept doubling before beginning to settle down to the more sedate expansion originally described by the Big Bang theory.
Guth's
theory of inflation - the name he coined for this superfast early-universe expansion - has since vanquished every theoretical challenge and grown stronger with each new cosmological finding, including the latest, largest one: that the universe's expansion rate, long thought to be slowing, is actually accelerating. "There's no competition, but that's not for lack of trying," says cosmologist Alexander Vilenkin.
Meanwhile, the time has come to contemplate inflation's largest implication, one that seemed overreaching for an uproved theory in 1979 but that now must be faced squarely. The whole universe may be, to use Guth's phrase, "a free lunch." The primordial "stuff" of inflation, he and other cosmologists contend, is very likely a spontaneous creation, a no-strings gift that boiled out of absolutely nowhere by means of an utterly random but nonetheless scientifically possible process. Now that inflation theory is approaching dogma, it is bringing science to the brink of answering one of the largest questions of all:
Why is there something rather than nothing? "It's not a coincidence that the Bible starts with Genesis," he says..."Most people really want to know where we came from and where everything around us came from..."
"...if, in a larger sense, nothing in this universe is ever "purchased" without an exchange of energy, how can the whole universe be free?"
"Start, Guth says, by imagining nothing, a pure vacuum. Be careful. Don't imagine outer space without matter in it. Imagine no space at all and no matter at all. Good luck.
To the average person it might seem obvious that nothing can happen in nothing. But to a quantum physicist, nothing is, in fact, something. Quantum theory holds that probability, no absolutes, rules any physical system. It is impossible, even in principle, to predict the behavior of any single atom; all physicists can do is predict the average properties of a large collection of atoms. Quantum theory also holds that a vacuum, like atoms, is subject to quantum uncertainties. This means that things can materialize out of the vacuum, although they tend to vanish back into it quickly. While this phenomenon has never been observed directly, measurements of the electron's magnetic strength strongly imply that it is real and happening in the vacuum of space even now.
Theoretically, anything - a dog, a house, a planet - can pop into existence by means of this quantum quirk, which physicists call a vacuum fluctuation. Probability, however, dictates that pairs of subatomic particles - one positive, one negative, so that conservation laws are not violated - are by far the most likely creations and that they will last extremely briefly, typically for only 10-21 second. The spontaneous, persistent creation of something even as large as a molecule is profoundly unlikely.
Nonetheless, in 1973 an assistant professor at Columbia University named Edward Tryon suggested that the entire universe might have come into existence this way. In a paper titled "Is the Universe a Vacuum Fluctuation?" he stated, "I offer the modest proposal that our Universe is simply one of those things which happen fromtime to time." Others scoffed at the idea. If a from-nothing, briefly existing molecule is absurdly unlikely...a from'nothing, 15-billion-year-old universe is vastly less likely.
Then, on November 13, 1978, Guth, while doing postdoctoral research in particle physics at Cornell University, chanced to stroll into a lecture on the Big Bang given by Princeton cosmologist Robert Dicke.
Dicke's topic was the flatness problem, one of the Big Bang theory's biggest mysteries. Dicke explained that somehow the universe seems to be extremely "flat," which means matter, velocity, and gravity all balance to put space-time precisely on the dividing line between a "closed" and an "open" geometry, In a closed universe, space-time curves back on itself, such that light beams that start out parallel will actually meet. In an open universe the beams will diverse. The value of omega describes the ration between the average density of matter in space and what that density would need to be to make the universe perfectly flat. If omega equals one, the universe is flat.
Guth states "According to classic Big Bang theory, as the universe evolves, the value of omega is always driven away from one...So if the universe starts out with an omega value of less than one, omega gets raidly smaller as the universe ages. If it starwts with omega greater than one, omega gets rapicly larger. The fact that omega is very close to one today - microwave background radiation measurements indicate it is within 10 percent of one - means that, according to classic Big Bang theory, one second after the bang, omega would have had to be between .999999999999999 and 1.000000000000001. But why? "I was intrigued, " says Guth. "How could that number start out so finely tuned?"
On December 6, 1979...Guth sat down at his desk and came up with the breakthrough that he called inflation. He realized that omega did not have to be preposterously fine-tuned from the start. An exponentially expanding early universe, which he would come to call the inflationary universe, would drive omega toward one, now away from it, making a flat universe inevitable.
Return to that primordial vacuum, a boiling stew from which pairs of positive and negative subatomic particles bubble into being for the briefest of instants. Inflationary theory suggests that what erupted was a "false vacuum," a peculiar form of matter predicted to exist by many particle theorists, although the real article has never been observed.
A false vacuum is characterizedby a repulsive gravitational field, one so strong it can explode into a universe. Another peculiarity of the false vacuum is that it does not "thin out" during expansion as, say a gas does - the density of the energy within it remains constant even as it grows. So the false vacuum's expansion, accelerating exponentially as its repulsive force compounded, actually created vast quantities of ever-doubling energy, which decayed into a seething plasma of particles such as electrons, positrons, and neutrinos. As the early universe went along doubling every microsecond, the stuff in it doubled, too--out of nowhere. The elctrons, positrons, and neutrinos became a sort of hot soup, which 300,000 years later neutralized to form simple atoms. The simple atoms, like hydrogen, helium, and lithium were ripped apart and crushed together to form more complex, heavier atoms inside stars. Exploded into space by supernovas, they became the matter we see - and are - today.
The initial bit of false vacuum required by Guth's calculations turned out to be mind-bendingly small: A patch one-billionth the size of a proton would do. And the required period of exponential growth was very short. In perhaps just 10-34 second, he suggested, the universe expanded by 25 orders of magnitude, to roughly the size of a marble, an increase equivalent to a pea growing to the size of the Milky Way.
The inflationary process, Guth discovered, would push omega toward one with incredible swiftness. The reason is best expressed by analogy. The universe appears to be virtually flat for the same reason that Earth's surface appears to be virtually flat to a person standing on that surface. The very fabric of space becomes relatively "stretched" so that in as few as 100 doublings in size, its curvature is effectively canceled.
And what about the conservation of enerty: According to Einstein's theory of relativity, the enerty of a gravitational field is negative. The energy of matter, however, is positive. So the entire universe-creation scenario could unfold without breaking conservation-of-energy laws. The positive energy of all matter in the universe could be precisely counterbalanced by the negative energy of all the gravity in the universe.
This also is mre than theory. Observations are consistent with the idea, and calculations totaling up all the matter and all the gravity in the observable universe indicate that the two values seem to precisely counterbalance. All matter plus all gravity equals zero. So the universe could come from nothing because it is, fundamentally, nothing.
There is much more in this article which can be found at the following web site:
www.discover.com. Guth also makes the statement that an advanced race could harness the engines of inflation and create a whole cosmos from scratch. Indeed, our universe could be such a creation.
Regards, Shuckins
