It is cosmology’s most fundamental question: How did the universe begin?
The question presupposes that the universe had an actual starting point, but one might just as well assume the universe always was and always will be. In that case, there would be no beginning whatsoever — just an ever-evolving story of which we’re catching a mere glimpse.
“We have very good evidence that there was a Big Bang, so the universe as we know it almost certainly started some 14 billion years ago. But was that the absolute beginning, or was there something before it?” asks Alexander Vilenkin, a cosmologist at Tufts University near Boston. It seems like the kind of question that can never be truly answered because every time someone proposes a solution, someone else can keep asking the annoying question: What happened before that?
But now Vilenkin says he has convincing evidence in hand: The universe had a distinct beginning — though he can’t pinpoint the time. After 35 years of looking backward, he says, he’s found that before our universe there was nothing, nothing at all, not even time itself.
Throughout his career, including the 20-plus years he has directed the Tufts Institute of Cosmology, Vilenkin has issued a series of wild, dazzling ideas, though from the outside he looks neither wild nor dazzling. The 64-year-old professor is soft-spoken, trim and of modest build. He dresses neatly, in neutral, understated tones that don’t draw attention to him.
Despite a low-key manner bordering on subdued, Vilenkin is a creative force who has continually found ways of piercing the fog surrounding some of the densest quandaries imaginable — triumphs that have earned him the respect of scholars worldwide. “Alex is a very original and deep thinker who has made important and profound contributions to our notions about the creation of the universe,” says Stanford cosmologist Andrei Linde.
Yet this brilliant career might never have happened. Born in the Soviet Union in 1949 and raised in the Ukrainian city of Kharkiv, Vilenkin got hooked on cosmology in high school, after reading about the Big Bang in a book by Sir Arthur Eddington. That “obsession” over the universe’s origins, Vilenkin says, “has never left me. I felt that if you could work on this question, which may be the most intriguing one of all, why would you choose to work on anything else?”
As an undergraduate at Kharkiv National University, Vilenkin says he was advised to “do some real physics” rather than pursue his first love, cosmology. Although he was an excellent student, he could not get into any graduate programs in physics because, he suspects, the KGB blacklisted him for refusing to become a government informant. Instead, Vilenkin was forced to take a series of mundane jobs. For a while he taught night school for adults but left that position because his responsibilities included going to the homes of absentees, many of whom were alcoholics, to try and drag them to school — an unenviable task.
He was a night watchman for about a year and a half, including a stint at the Kharkiv Zoo. To protect the animals (which were sometimes hunted for food), he was given a rifle that he didn’t know how to use and fortunately never had to fire. When he had time during those long nights, Vilenkin studied physics, an avocation that included reading the four-volume collected works of Albert Einstein. He got fired from this plum assignment when someone decided — perhaps based on his choice of reading material — that he was overqualified for the task at hand.
With his employment prospects looking bleak, he decided to emigrate to the United States; he figured he’d start out washing dishes while trying to break into academia. But getting out of the Soviet Union required an elaborate plan: Jews like him were allowed to go to Israel in small numbers, determined by a quota, but one had to secure an invitation from Israeli relatives first. Vilenkin had no actual relatives there, so he contacted a friend who knew people in Israel and eventually found someone — a stranger to him — kind enough to write a letter on his behalf.
After the letter arrived, he waited a year for a visa, but it came at great cost. Before Vilenkin and his wife could leave, their parents had to consent to the move. For giving their permission, his wife’s parents lost their laboratory jobs. His father, a university professor, later lost his job, too. The traditional stop en route to Israel was Vienna, but from there Vilenkin, his wife and 1-year-old daughter went to Rome instead, arriving in 1976. They met with the U.S. Consulate in Rome and, after a three-month wait, were finally granted a visa to the U.S.
Back to the Big Bang
In fall 1977, Vilenkin took a postdoctoral position at Case Western Reserve, where he was supposed to study the electrical properties of heated metals. Still, he found time on the side to theorize about spinning black holes and their mysterious magnetic fields. A year later, he got his lucky break when Tufts offered him a one-year visiting position. He took a gamble by poring himself into cosmology, an area considered fringe at the time.
That would soon change. In late 1979, a Stanford physics postdoc named Alan Guth offered an explanation for the explosive force behind the Big Bang. Guth’s intellectual leap stemmed from theories in particle physics, which held that at extremely high energies — far higher than could ever be reached in a laboratory — a special state of matter would turn gravity upside down, rendering it a repulsive rather than an attractive force.
A patch of space containing a tiny bit of this unusual matter could repel itself so violently as to literally blow up. Guth suggested that a tremendous burst of this sort triggered the Big Bang, swiftly enlarging the universe so much it doubled in size at least 100 times. This exponential growth spurt — called cosmic inflation — was short-lived, however, lasting just a tiny fraction of a second because the repulsive material quickly decayed, leaving behind the more familiar forms of matter and energy that fill the universe today.
The idea simultaneously solved a number of puzzles in cosmology. It explained where the “bang” behind the Big Bang came from and how the cosmos got so big. Rapid inflation in every direction also explained why the universe we now observe is so homogeneous, and why the temperature of the background radiation left over from that primordial blast is uniform, in every patch of the sky, to one part in 100,000. Inflation also revitalized cosmology, giving theorists like Vilenkin plenty to think about — and a bit more respectability to boot.
The Never-Ending Story
By 1982, a couple of years after Guth’s breakthrough, Vilenkin had a realization of his own: The process of inflation had to be eternal, meaning that once it started, it never fully stopped. Inflation might end abruptly in one region of space, such as the one we inhabit, but it would continue elsewhere, setting off a never-ending series of big bangs. Each bang would correspond to the birth of a separate “pocket” universe, which might be pictured as an expanding bubble — one of countless bubbles floating around within the “multiverse,” as it’s sometimes called.
As Vilenkin saw it, inflation’s eternal nature stemmed from two competing properties of the cosmic fuel, the gravity-repulsive material that caused the universe to rapidly expand. On the one hand, the material was unstable, much like radioactive substances, and was thus doomed to decay. On the other hand, the material expanded far faster than it decayed, so even though decay might stop inflation in certain regions, runaway growth would continue in others.