Approximately 13.7 billion years ago - give or take an insignificant 260 million years - the piping hot primordial jambalaya of the original universe began to expand. Physicists now agree we shouldn't have called it the Big Bang. The Big Wheeze would have been more accurate. It happened everywhere at once.
About 13.7 billion years later - in layman's terms, a few weekends ago - 180 of the world's top theoretical astrophysicists gathered at the University of Toronto to congratulate each other on figuring out that number.
Say those words: theoretical astrophysicist. It may not sound like a real job. But they were celebrating the 25th anniversary of the Canadian Institute for Theoretical Astrophysics.
Most Canadians don't know it, but CITA is one of the world's crack centres for theoretical astrophysics, the equal of Stanford, Cal Tech, Cambridge University or Princeton.
"It's a world-class institution that has dominated its field," says Wendy Freedman, director of Pasadena's Carnegie Institute of Science.
The brainiacs gathered in the nondescript brown brick McLennan building, where physics is taught at U of T, were also celebrating the 60th birthday of J. Richard (Dick) Bond. The BondFest bore a resemblance to a weekend blowout for very, very intelligent frat boys, which Prof. Bond was before he became one of the world's most-cited cosmologists and a past director of CITA, where he collaborated with almost everyone in the room.
For four days, the astrophysicists drank coffee and wine, made physicist jokes about Prof. Bond ("the force we call Dick") and delivered detailed lectures about accreting millisecond X-ray pulsars and other impenetrably cutting-edge work. It was not a big crowd. Norman Murray, the current director of CITA, was nursing a beer at the opening reception when he ventured that only 100 people in Canada, and maybe 1,000 worldwide, understand the mathematics of early-universe physics.
"By 'early'," Dr. Murray added (physicists like to add things), "most people mean the first fraction of a second after the Big Bang."
That's what it's like talking to astrophysicists: They say a clear, fascinating thing, and follow it with endless upsetting complications. This is the way they tell the truth. The difference between them and most people is that astrophysicists aren't afraid of what they don't understand. That approach stood CITA in good stead for a quarter of a century as it roamed the skies in search of what even two decades ago seemed like the unanswerable.
But astrophysics is changing, and not just theoretically. Having proved how the universe developed, CITA and its band of merry speculators face daunting new challenges. The field has grown exponentially, the cost of experiments is through the roof and competition for research dollars is reaching fireball temperature - especially with radical competitors such as Waterloo's BlackBerry-funded Perimeter Institute for Theoretical Physics in the hunt.
More to the point, the easy problems in the universe have been solved. We have a fair idea how all this got here. Physicists now have to figure out why. That's a much harder question.
Catching the cosmic microwave
That the University of Toronto ended up as one of the world's leading centres of theoretical astrophysics was not a random event. In the late 1970s, a cell of thinkers within the Canadian Astronomical Society decided to create an institute for their big theories.
"We thought, well, for a little bit of money, because this is theory and not very expensive, we could have a big impact," remembers Peter Martin, one of CITA's founders.
Prof. Martin and his fellow sky watchers persuaded the National Science and Engineering Research Council to hand over $150,000 and held a competition as to which university would host the new institute. Toronto won. It was 1983.
Prof. Martin had trained at the Institute of Theoretical Astronomy at Cambridge under the legendary Sir Martin Reese (galaxy formation, quasars, now Britain's Astronomer Royal) and the late Fred Hoyle (stellar nucleosynthesis, panspermia). He wanted
CITA to have a similar structure - not a traditional faculty with graduate students, but a looser, creative think tank full of ambitious postdoctoral students.
"Graduate students are conservative," Prof. Bond points out. "They go to the big institution with the big name. But postdocs, they know what's happening. They follow minds."
The team hired Scott Tremaine, a Toronto-raised expert on the dynamics of galaxies, from the Massachusetts Institute of Technology, to be the first director and lured Dick Bond back to Toronto from Stanford. Two postdocs were hired the first year. Today, there are 24. They earn $55,000 a year.
Canada - a large and largely abstract country - turned out to be the perfect place for the congenial but competitive study of a large and abstract universe. "I think one of the main reasons
CITA was so successful," Dr. Tremaine says today, "is that astronomy was a pretty small world. And you can make a pretty big splash pretty easily."
But what actually set the CITA on its famous road to discovery was a confluence of events.
In 1964, a pair of Bell Lab radio astronomers trying to find clean television signals discovered they couldn't get rid of a persistent background hum. As it happened, a Winnipeg-born Princeton scientist named Jim Peebles (another CITA associate) had just written a paper speculating that microwave radiation was emanating from the universe as a relic of the Big Bang. Only after Arno Penzias and Robert Wilson, the TV repairmen, read Prof. Peebles's paper did they realized what they had found. They were awarded the Nobel Prize in 1978. Theoreticians seldom win the Nobel, but Prof. Murray and his colleagues still think it was unfair that Dr. Peebles didn't get the big one.
By then, the wave was out of the bag. The Cosmic Microwave Background, the waves emanating from the universe, was the past made visible - a cooled-down relic of the universe a mere 400,000 years after the Big Bang.
Over the next two decades, measuring and observing minute temperature fluctuations in the CMB (and other forms of space radiation) with radio, laser and other sophisticated telescopes, CITA and its global net of thinkers calculated backward and forward through space and time to hypothesize, test and prove what is now our understanding of how the structure of the universe evolved: from initial ripples in the early magnetoplasm created during the early instant "inflation" of the Big Wheeze (we still don't know what caused them), through dust clouds and along massive coalescing intergalactic filaments (some of them 300 million light-years long), which in turn bred galaxies and clusters of galaxies and black holes and stars and even planets around stars (400 so far, and counting). The pictures were hypnotic. There was, they discovered, a reassuring order to the universe.
"The great story," Prof. Bond says, "is how the technology, the computing advances and detector technology and the ideas all came together. It's like a wave of accomplishment. It has been like that in many fields, but if you're thinking about a subject that asks the biggest questions - for those to have been answered in one's working life is really an amazing thing." Better still, "it's not really challengeable. The facts are all there." He knows he and his colleagues have made scientific history. "When you discover the continents, you don't get to discover them again."
CITAzens (their word) study more than early-universe cosmology, of course. They examine star formation in our own galaxy ("you know, what's between the stars," Prof. Martin says), gravitational radiation (very cutting-edge), high-energy astrophysics and the search for Earth-like planets with the necessary conditions for life (a rocky core and water are two). The latter is the hot new thing drawing young scholars to the field. That's the thing about the universe, theoretical or otherwise: You never run out of stuff to think about.
They must be in it for the challenge, because it can't be for glamour or money
Theoretical astrophysics is allegedly easier to understand than some of the newer branches of quantum physics such as superstring theory (which is still not experimentally proven, though there's a very slim chance that might change, somewhat, with the new $4-billon Large Hadron Collider buried underneath France and Switzerland). Still, I defy any non-physicist to sit through "Differential Rotation and Magnetism in Fully Convective Stars" or "Observable Non-Gaussianity from String Inflation" or any one of the other 93 studies presented at CITA's gleeful weekend, and not feel afterward like a deaf-mute. Even cosmologists have difficulty keeping up: 30 to 50 new scientific papers are published every day on astronomy, while 10 to 15 more tackle fresh developments in cosmology.
But this is the strange thing about physicists: They're inspired by difficulty and collegiality. Money mostly doesn't matter to them. François Bouchet, director of research at the Institut d'Astrophysique de Paris, is in charge of data collection and analysis for Europe's $1.3-billion-plus Planck orbital radio telescope, launched a year ago - an experiment with nearly a thousand participating international scientists, rendering it a bureaucratic nightmare, for starters. For his hard work managing that and overseeing and interpreting the project's scientific output, Dr. Bouchet, who is in his 50s, lives in a small apartment in Paris on €70,000 a year. And that's about as good as it gets for a theoretical astrophysicist.
"It's a little bit like deciding to be a monk," he explains over a plate of Chinese food at CITA's weekend banquet dinner. Dr. Bouchet had spent the previous 20 minutes listening to Neil Turok, executive director of the Perimeter Institute, explain how his own backers expect results - even though Dr. Turok is currently working on the pre-inflationary moment of the Big Bang, which is still a vast mystery. It's no surprise a number of former CITA cosmologists have left the field for high finance - the applied math required for advanced astrophysics is only slightly more complicated than the equations that produced collateralized debt obligations.
Thinking deeply about the cosmic past isn't a social picnic either. Across the table, an Argentine-born Perimeter Institute fellow named Luis Lehner is lamenting the impossibility of a theoretical astrophysicist having a social life. (Astronomy is different: Some U of T astronomy classes are 50 per cent women. But there were only half a dozen female astrophysicists at the CITA think-in.)
Dr. Lehner adds: "What do you say? 'Yes, I am?' If you don't feel like talking, you say you're a physicist. If you do want to talk, you say you're an astronomer."
On the other hand, he and his colleagues all look 10 years younger than they are. "It's because we don't work 9 to 5 all day long. We get to do what we love."
Physicists love an elegant equation - but the reality may be much messier
However much they love their work, astrophysics will be harder for the next generation of theorists. The easy problems have been answered.
"In the old days, there was not that much data," Prof. Bond admits. "And so we could play. The younger people in the field are seriously constrained. Where are we at now? We are in quest of the subdominant and the anomalous."
Astrophysics is once again heading into unclaimed sky, into what physicists call anthropic theory. The ideal of physics, Prof. Martin points out, has always been "to get everything simplified into one simple equation." But the conditions required to explain persistently knotty aspects of the universe - dark energy and dark matter, which make up a majority of the stuff out there, or the statistical improbability that carbon will show up on a planet in a form that can support life (a fact that made even Fred Hoyle think the universe might have had a "guiding hand") - may require upsetting exceptions. There may be less order in the universe than the astrophysicists hoped.
"Our theories tell us most of the space in the universe is doing this accelerated expansion, but accelerating at much, much higher rates than we're experiencing in our pocket," Prof. Bond says. "So the rules of the game may depend on your own little pocket. Now there's an evolutionary aspect - survival of the fittest in the universe is where we're getting to. That changes the idea of what's fundamental."
These deeper conundrums will require larger experiments, more expensive telescopes and more powerful computers. (Tiny CITA is the second-heaviest user of SciNET, U of T's massive supercomputer.) Mike Lazaridis, the charismatic co-inventor of the BlackBerry, bravely seeded the Perimeter Institute with $170-million of his own fortune to study sexy, cutting-edge challenges in physics - cosmology is but one of six research pods. But Perimeter has also vacuumed up more than $175-million in federal and provincial grants since 2003. That's an average of $24-million a year - eight times the annual budget of CITA, despite CITA's international track record.
"The worry," former CITA director Scott Tremaine says (he went on to head Princeton's department of astronomy, and is now at its Institute for Advanced Study), "is that we'll get to the point where we can't understand things, but we won't be able to afford to get an answer. It's not like genomic biology, where for the next 20 years they know what they are facing - a long future of rapid progress."
But not everyone is worried. "I'd call it exciting," Peter Martin says. "When people like me started off, we had no idea what we'd be researching today."
As Norman Murray, CITA's current director, points out, the brand-new, year-old Kepler space telescope is already beginning to reveal Earth-sized planets outside our own solar system - places, in other words, that could support life. They will be huge discoveries.
The trick - the real act of faith - is to keep looking, gazing into the deep past by planning and paying for the immediate scientific future. After all, the Herschel Space Observatory, also launched a year ago, was first proposed in 1982 - when CITA itself was just constellating. Its latest pictures prove Herschel was a genius stroke of foresight, capable not only of peering into distant, gauzy galactic clouds where stars and planets are forming, but of tracking intragalactic paths of life-forming water molecules.
"Some people didn't live to see its results," the 62-year-old Prof. Martin says. It's the only time his scientific rigour goes wistful. "I'm hoping I live long enough to see some of it."
Ian Brown