Bright sparks and black holes
Roy Kerr is a genuine genius. JOHN McCRONE profiles the former St Andrew's College pupil who will this year be awarded the prestigious Albert Einstein Medal.
Imagine being born Einstein smart, equipped from birth with a brain big enough to win the Nobel prize, but also being born the son of a womanising garage manager in 1930s Depression-era Gore.
Your mother forced out of the family home when you were 3 years old. Shuffled off to a farm when Dad went to war. Idling away your formative years in a country school, no mental challenge beyond the thin shelves of the local library.
How do you overcome such unlikely beginnings to become New Zealand's most illustrious living scientist? Does genius always out?
I find 78-year-old Roy Kerr in a house tucked just over the back fence of Christchurch International Airport.
He explains his wife Margaret breeds pedigree golden retrievers, so they need a yard with no neighbours. Yet it also seems symbolic to discover Kerr right under local noses, almost under the wing of every landing plane, but largely invisible.
With a beam, Kerr invites me in. Looking sprightly for his age, he settles in a wicker chair, and relates the story of his complicated life.
It is a tale of could-have-beens and should-have-beens. But also that moment in 1963, when at only 29, he cracked a mathematical conundrum which had been stumping relativity theorists for 50 years and so proved black holes could exist.
Kerr continues to get belated recognition for this tremendous breakthrough. In May, he flies to Zurich to pick up the Albert Einstein Medal from the old guy's former university - an honour shared by only the Who's Who of theoretical physics.
Yet there are those who still wonder how Kerr has been overlooked for the Nobel despite being nominated several times. He could have ended up on our banknotes like Lord Ernest Rutherford.
So is his a tale of the plucky Kiwi outsider? Of genius triumphing against the odds? Or maybe of the lucky fluke - the one- hit wonder?
Kerr laughs generously. It is tough cutting a life down to fit a Hollywood plotline. But yes, we can have a go.
The rocky childhood start turns out to be not much of a clue.
Kerr agrees it was rough having a dad with too many girlfriends. "It was very hard on my mother," he says. "In those days, if you separated, the woman just had to go off with no support."
And his father was a difficult person. One haunting memory is of him returning from World War II and being unable to exchange a single word with Kerr for several days. "A lot of people didn't last very long around him."
Kerr was moved to Christchurch when a step-family followed his father out from England. He slept under the leaking roof of the factory where after school he helped out with his father's new business venture - cutting up old inner tubes to make rubber band seals for jam jars.
"I was 12 and we were putting the bands into packets. I kept figuring out ways to do this faster until I was counting out 25 rubber bands and folding everything up in six seconds. No-one else could get anywhere near that speed."
But Kerr says his childhood gave him a reason to aim for something better in life. Starting his education was the real problem.
A lucky break was getting into private St Andrew's College because his father had served under the former headmaster. However, Kerr says the school was at a low ebb. "Most of its real teachers had died during the war."
The chemistry teacher was a failed lawyer, the maths teacher a chaplain who could not even add up Kerr's exam marks properly.
"He was giving back the papers this one time and goes '. . .and Roy Kerr's not got 100 per cent, he's only got 83 per cent'. So the class goes 'Yaay!' But I look through and it's full marks, full marks - 'Hey sir, you've only added up five of my answers'."
Despite dishing his final scholarship chances - Kerr turned up in the afternoon for one of his morning mathematics papers - his exceptional ability had been recognised and at 16 he was admitted into the third year of a maths and physics degree at the University of Canterbury.
Kerr says the standard of teaching was not a lot better than at school. As a dusty outpost of empire, Canterbury University College, as it was known then, was still teaching a 19th-century syllabus. Relativity and quantum mechanics were but distant revolutions.
"It was all very interesting, but there was nothing from the 20th century like group theory."
Kerr was a prodigy, ripping through his courses with ease. "In my first mid- year exam, I probably got 30 or 40 per cent more marks than the No 2 guy - who was a third-year student, a very nice chap, who went on to become New Zealand's best applied mathematician."
After two years of a four- year masters degree, Kerr had absorbed all the university could teach. He should have gone to Cambridge University on a waiting scholarship, but due to some administrative interference, he was held back and left twiddling his thumbs.
Kerr boxed in the university team, played billiards, whiled away some time doing random papers on ethics. Athletic and sociable, Kerr was no awkward maths geek.
Yet once more he was idling in the shallows. And it had an unfortunate consequence when he arrived in Cambridge in 1954.
In his eagerness to finally get going, Kerr skipped the further undergraduate training that might have eased his passage into the tight-knit world of academic research and plunged almost immediately into a maths doctorate under a random series of thesis supervisors.
His first happened to be the world's top algebraist, Philip Hall. "So Cambridge must have thought I had some ability, I guess." But Kerr had barely studied the subject.
"I didn't know any modern algebra and now I'm planning to do a PhD on it," he chuckles, laughing at what must have been a ludicrous self-confidence on his part.
Kerr says he had grown too accustomed to educating himself by skimming the right books. His relationship with Hall came to an abrupt end when it was suggested Kerr should bone up on discrete algebraic groups and Hall found him instead reading about continuous groups.
It was an almost schoolboy level mixup. "I confused the two and he got mad, so I thought, well, I better go do physics."
Next Kerr got another luminary as his supervisor - the future Nobelist Abdus Salam. But Salam was a particle physicist and Kerr had even less grounding in that, so again the relationship did not last long.
By the time Cambridge dug up a third PhD supervisor, the authorities were clearly losing patience. "This guy must have been 27th down the line. I asked around and nobody else at the university had even heard of him."
Kerr only met him once to say hello. Continuing his haphazard journey from Gore, Kerr drifted off on his own to help a friend, agreeing to do the mathematical grunt work on a theory in yet another area he had barely heard of, let alone studied.
Kerr was really too bright for his own good. He had risen fast because people always allowed him to jump ahead. But this also meant he remained outside the established academic networks.
He did not have a mentor guiding him, a teacher steering him on to a path to match his talents.
Kerr also appears to fall between two ways of thinking - that of the mathematician and the physicist.
Mathematicians could not care less about the real world, says Kerr. They live in their private realm of discovered patterns. Yet he found maths interesting only where it appeared to be saying something deep about reality.
On the other hand, Kerr felt physicists were too ready to play it fast and loose with their mathematics. It was enough for them to sketch out an idea with some equations that looked as though they might do the job.
Kerr says physics has a different notion of quality control because the maths can always be fixed up later. What matters is producing predictions plausible enough to be experimentally tested.
However, Kerr had a gift for spotting the mathematical flaws of a theoretical argument at a glance. His eye would light upon an equation and he could say, well this is never going to work out. There is no getting here from there.
It is an ability that has plagued him.
"You know, you're supposed to go from step one to step two to step three, but I just would jump from one to five to eight in my thinking."
Writing up his own ideas was always a chore because he could see the end from the start and so could barely be bothered filling in the gaps for others.
Kerr confesses it was also a trait that proved as irritating as hell for his colleagues as he came across as the party-pooper. "I always seemed to be in this negative position of telling people that their mathematics was lousy and so their theory can't be true."
In this way, Kerr seems almost un-Kiwi. Although he is an easy- going character most of the time, quick to laugh at life's absurdities, he concurs he has a narrow, almost old-fashioned, belief about the right way to do science.
Whereas, in his view, it is mostly everyone else in fundamental physics who is happy with a "she'll be right" approach to theory building.
Eventually, for a short while after leaving Cambridge in 1959, Kerr did find his niche.
The 60s were the golden age of relativity theory, when scientists began to extract a whole range of important cosmological consequences from Einstein's famous equations. The mathematics started to produce physically meaningful results.
Kerr got into relativity theory sideways through helping out his Cambridge colleague, John Moffatt. Moffatt's theory did not pan out - no surprise to Kerr. He soon saw it had more undefined variables than the equations could keep track of.
"We wrote a paper up, but it was never going to work," Kerr says with a dismissive shake of the head. But the collaboration did give him experience in handling the maths of the complicated motions of bodies moving in curved space time.
So Kerr ended up doing his thesis on the gravitational interactions of planets and stars - the kind of results that astrophysicists could use, he says with satisfaction - then moved on to a succession of post-doctorate research positions in New York, Ohio and Texas.
Relativity was still a small world at this point with perhaps a half dozen serious university groups. And with the US Air Force vying with the US Navy for the prestige of funding the research, the Americans had come into some extra money.
So at last Kerr found himself in the thick of things, in hand-to-hand combat with a gang of other bright young minds. The kid from Gore had finally reached the centre of the action.
Kerr continued to plug away at his many body physics, his thesis material, pursuing a grand project to boil down Einstein's 10 field equations to something simpler. If he could find a way to drop any unnecessary assumptions, then something valuable was sure to pop out of a more condensed theory.
Kerr says even Einstein had felt this was an impossible task.
There had been one such early success when in 1915, the German Karl Schwarzschild - while serving on the Russian front - had produced a result suggesting that a big enough mass must collapse under its own gravitational field to form a singularity - a black hole with gravity so strong even light could not escape its grip.
But Schwarzschild's argument was rather simple and most people treated his black holes as physically unlikely - just science fiction speculation. For the next 50 years no-one else could squeeze anything much better out of Einstein's equations.
In the US, several others were working on the same problem. Kerr says in 1963 a rival Syracuse University team produced a paper which he saw contained some fatal mathematical blunders.
Realising this gave him his opportunity, Kerr "went mad" for several weeks and managed to produce his own still horrible, but rather more tractable framework of equations.
The mental gymnastics involved are arcane. But it came down to visualising how different mathematical objects were actually the same thing if switched about in the right fashion - in this case, a symmetric spinor and conformal tensor, if you are interested, says Kerr.
He continued to strip down the equations until eventually he was left with two terms, two parameters, that Kerr could recognise as likely to stand for a mathematical description of a flat space containing a spinning object.
Excited, he grabbed his boss, University of Texas physics professor Alfred Schild, and they sat together to make the final calculation. Schild was in an armchair, puffing away on a pipe, watching while Kerr scrabbled out the last steps.
Then came the moment when Kerr could look up and exclaim: "It's rotating!"
OK, that is getting a bit too Hollywood, he admits. It took some time to understand he had stumbled on the only possible precise mathematical description of a spinning black hole, and not just any old spinning object.
But he had achieved the result that will for ever more be known in physics textbooks as the discovery of the Kerr metric.
It was big. Huge even. A basic finding from which much else was to flow. But for Kerr, there was an element of bad timing about it.
Earlier that same year, without realising it, astronomers had discovered actual black holes in deep space. Their radio telescopes had picked up some unnaturally bright stars or quasars (quasi- stellar objects) in distant galaxies.
Astrophysicists were agog. And by a twist of fate, Kerr's own professor, Schild, was helping organise an international conference in Dallas to discuss them. It seemed the perfect opportunity for Kerr to present his findings.
But it was too soon for the connection between the two to be grasped.
The astronomical community was not even considering black holes as a possible quasar mechanism at that stage and so they brushed over his paper.
When Kerr got up to speak, many slipped out. Others chatted in the rows or catnapped.
Kerr has since been thoroughly vindicated. Quasars are black holes glowing hot with all the surrounding matter they drag in. Black holes are believed to litter the universe.
Indeed, our own galaxy has a supermassive one, Sagittarius A*, whirling at its heart, the size of four million suns.
If quasars had been discovered just a few years later, long enough after Kerr's calculations to look like the confirmation of a bold scientific prediction, then as a junior scientist, only loosely attached to any recognised research group, he might have been treated rather differently.
Instead, he says, he felt like meat being tossed to the lions. As soon as others studying relativity saw what he had achieved, they began trying to snatch the glory for themselves.With no-one to protect his back, he seemed fair game.
"They all wanted a piece of the pie.
"There was one famous 40-page paper to prove that the angular momentum was what I said it was. Yet I had already done it in a four- line proof."
Schild did become a benefactor, getting Kerr a full-time post as a professor of mathematics at the University of Texas.
Looking back, Kerr feels he was poised on the verge of greater things as his next natural step would have been foundational work on gravity waves - a field of relativity that is only now coming into its own.
However, Kerr became disillusioned by the politics and the way other physicists were taking his Kerr metric and spinning it into flights of fantasy way ahead of any definite mathematics.
With so few genuine results to go round, he says, most theorists have to take some flawed idea and promote it.
He thus ended up on the outer again, unable to join anyone else's group because their mathematical shortcomings seemed too obvious. "I could see their approaches would be doomed to failure" - but also then not tied to any group that might want to promote his reputation.
"By 1966 or 1967 I just got depressed. There's no other way of looking at it," says Kerr.
He began to do other things. He got passionate about bridge and golf.
"With bridge, all I had to do was win. I didn't have to explain to people why they were silly to do this, and that they should be doing that."
He won national titles and invented new bidding systems. Kerr says golf was the same. He positively purrs as he recalls once standing on a tee and hitting six perfect 2 irons in a row just because he could.
In 1971 Kerr returned to Christchurch on sabbatical and in 1983 took over Canterbury University's mathematics department.
By this time his scientific contribution was becoming increasingly well recognised and when he wasn't representing New Zealand in bridge tournaments, he was travelling to Brazil or Italy as an honoured conference guest.
In 1993 Kerr retired early, with the idea of sailing the world in a yacht. That ambition lasted a single storm and demasting off the West Coast.
As professor emeritus, he has remained on the scientific circuit as a spectator and commentator.
At 78, Kerr believes he has still got it. He says there is this little idea he has about negative particles that would have repulsive gravity. If he can refine the mathematical detail, he might just alarm his hosts with a presentation when he collects his Einstein Medal in May.
Does a Nobel remain a possibility? Kerr shrugs. It is a little late in the day. And these things are like Oscars. It helps who you know.
But certainly the value of what he did is becoming more apparent every year. And, in relativity theory, no other person has made an equivalent advance since his 1963 paper.
"I may not have done anything as significant again - but then the point is that neither has anyone else."
Standing at the door to say goodbye, Kerr looks the tanned and fit pensioner.
The unremarkable face you might have bumped into around Christchurch any day recently.
But the far from ordinary brain. Quite definitely the cleverest kid to have ever come out of Gore.