It was Einstein’s unfinished business. The world’s best-known and most prolific physicist was driven in his latter years to find a single set of laws for the universe: laws that would apply as readily to the chaotic BeBop of sub-atomic particles as to the majestic waltz of galaxies in deep space.
Einstein failed. But on the 100th anniversary of E=mc2, a new generation of physicists is carrying the torch and offering the answer to Life, the Universe and Everything. They say the answer is string theory.
Problem is, string theory is too weird for most people to understand. Some scientists even say it’s more fiction than science.
Not Michio Kaku. One of the world’s best-known theoretical physicists, and one of the key players in string theory, he is a professor at the City University of New York. Not only is Kaku ‘sold’ on string theory – and one of the earliest players in its development – he is also a passionate proselytiser. He has just completed a world tour for his third popular science book, Parallel Worlds, and is working with the BBC on a documentary series.
But it is not just the desire to spread the word about string theory, physics and the intrinsic value of science that drives him to engage the public. Kaku believes that the very future of the human race is on the line. “We’re at a precipice; we are experiencing the birth pangs of a ‘Type 1 Civilisation’. And there’s no guarantee we’ll make it.”
I met Michio Kaku in San Francisco, and I must confess to great trepidation before the interview. He is an imposing man. Besides being an author of popular books (his earlier book, Hyperspace, was a global bestseller), he’s also written one of the key textbooks of quantum field theory and, together with Keiji Kikkawa of Osaka University in Japan, published two of the seminal papers describing string field theory. I imagined he would not suffer fools lightly.
Nevertheless, repeated desperate efforts to get a handle on this field had led me nowhere. Or rather, to some very weird places: extra dimensions and parallel universes. Somehow this was supposed to follow from the proposition that the fundamental building block of matter is not the quark [atom-smashing physicists have shown that the protons and neutrons at the heart of atoms are actually composed of quarks] but something even smaller – a million billion times smaller – a vibrating string.
Presumably all could be fathomed – if only I understand N-dimensional mathematics. But my background is in biology, and I feared I would be quite incapable of asking him anything intelligent.
As it happened, the night before the interview, I had dinner with three bright, mathematically proficient engineers and a Stanford University neuroscience professor. As a last resort, I asked them for help. What would they ask Michio Kaku?
To my great relief, their difficulties were the same as mine. On my right, a brilliant PhD engineer from Odessa, candidly admitted: “I really can’t conceive of extra dimensions.” To my left, another smart engineer offered his view that physicists had gone awry by taking mathematical concepts like zero and infinity in a literal way. He believed they were only meant to be used in a symbolic way. Surprisingly, it was the neuroscience professor who was the most receptive to string theory. He offered, “It’s up to these physicists to get us out of the mess we’re in. We may have to get off this planet.”
And so, I found my opening line for the interview. I gingerly suggested that the new physics of string theory seems to affront some people (especially engineers) as if they suspect ‘real science’ had been hijacked. The silver-haired, avuncular Kaku fixed me with kindly brown eyes and settled into what was clearly a familiar role: that of the patient, tolerant, and at times mischievous college professor. It also became immediately clear that the tussle between engineers and physicists was nothing new.
Physicists and engineers have long failed to see eye to eye, he began. “Engineers want to build bridges; physicists want to understand fundamental laws,” he said. “Engineers disdained Einstein’s theories, but those equations ultimately resulted in the atom bomb.” Einstein was Kaku’s hero. He first heard of Albert Einstein at the age of eight, when he learned the great scientist had died and left behind a book with an unsolved mystery. “I wanted to know what was in that book; to me it was more fascinating than any adventure story. What problem was so difficult the great Einstein himself couldn’t solve it?
“Today we believe that [the answer to Einstein’s quest for the unified field theory] is string theory. It also makes the engineers’ eyes go crazy, because we are talking about universes that are unseen.” Having expertly trussed his sacrificial engineer to the whipping stand, Kaku proceeded to explain the quest that has captivated him since the age of eight.
Understanding other worlds came naturally to him. Perhaps it was an inevitable consequence of being the child of Japanese Americans. His parents, though born in California, spent World War II behind barbed wire, guarded by people with machine guns: incarcerated by their own country as enemy aliens. Afterwards his father worked as a gardener, his mother a maid: two of the few jobs that were available to Japanese Americans. Kaku grew up poor, but one of the family treats was to visit the Japanese Tea Garden in San Francisco’s Golden Gate Park. It turned out to be the place of a childhood epiphany. Wondering in the way that only a child does, Kaku looked at the carp swimming in a weedy pond and imagined how they would not be able to conceive of other worlds. “A carp engineer would believe that was all there is; but a carp physicist would see the ripples on the surface and start thinking about unseen dimensions,” Kaku told me, laying the first of many lashes on his token engineer.
Kaku’s curiosity and penchant for unearthly thinking were largely misunderstood, a large part of the reason why today he has become a light unto others. “When I was a teenager and asked questions, eyes would glaze over – I didn’t want others to go through the trials of fire.”
But his teenage curiosity did pay off. “Because my parents were poor, I knew from a very early age that I would have to be self-reliant. Hence, in high school, I built a 2.3 million electron volt atom smasher, which helped me to get into Harvard. My parents did not understand at all what I was doing, but they realised it was important, and helped in any way they could. The atom smasher used up 22 miles [35km] of cooper wire, which my parents and I wound on the high-school football field over Christmas vacation.”
The atom smasher consistently blew the fuses at his parents’ home. But it also impressed atomic scientist Edward Teller, who arranged a scholarship at Harvard University for the young Kaku.
Early on, college life proved quite prosaic for Kaku. It involved learning the bread and butter of physics – most tediously having to memorise Maxwell’s eight hideous mathematical equations that describe electromagnetic fields. But the physics course kept the best till last. In the advanced class, Kaku experienced an epiphany to rival that of the carp in the tea garden. “We physicists have the greatest mind-blowing coming of age; its an existential shock.”
What Kaku learned was that Maxwell’s eight lines of equations, could be reduced to one. The shock was that this equation magically rose out of Einstein’s gravity equations if you added a fifth dimension! (that is, a fourth spatial dimension: we are used to three spatial dimensions and one of time). “That’s the difference between engineers and physicists: engineers are happy with Maxwell’s original equations; they think ‘how horrible but how useful’.” Physicists, however, are looking for the underlying elegant logic of the universe. And according to proponents of string theory that logic is: physical laws become simpler in higher dimensions.
The five dimensional transformation of Maxwell’s equations is not controversial: it works. Indeed mathematicians often operate in extra dimensions. Where the controversy lies is whether these mathematical abstractions have any counterpart in the real world. String theory physicists believe they do; not just in five dimensions – but in 11!
The bitter wartime experience of Kaku’s parents did not dent his own patriotism. In 1969, just three days after graduating from Harvard, he enlisted into boot camp at Fort Benning in Georgia, one of thousands of raw recruits being hammered into a fighting force to replace the 500 GIs dying every week in Vietnam. While dodging bullets, he would conceptualise the maths of how strings could move through space as loops. These revelations later became the basis for his PhD dissertation at the University of California at Berkeley.
It turns out it is no easy matter to create a universe where matter, space and time are stable. For it all to work, the fundamental forces must be unified. And that unification can only take place in higher dimensions. As Kaku puts it, “Forget building bridges, we’re talking about being God. This is what Einstein dreamt about every day of his life. If I’m God, how do I create a stable universe? It’s extraordinarily difficult.”
When he is not working, Kaku spends a lot of time popularising science. He is a gifted writer, whose vivid narratives sweep breathtakingly not only across alternate universes, but across art, history, politics, literature, philosophy and religion. His own religious influences were contradictory: his parents were Buddhist, but he was raised as a Presbyterian. Yet modern physics seems to accommodate both views.
“In Christianity, there in an instant of creation; while in Buddhism there is Nirvana, which is timeless,” he says. “I am pleased that modern cosmology provides a beautiful melding of these two mutually contradictory ideas: continual genesis taking place in a hyper-dimensional timeless Nirvana.”
He has also hosted a regular science talkback show on U.S. public radio for the past 20 years. It is not just for the love of physics that he popularises: Kaku has peered deep into the future, to the time when the universe is ancient, dying and darkening; a time when Earth’s inhabitants will need to find themselves a home in another universe. String theory predicts parallel universes. That means mass evacuation through a wormhole might be the key to survival; if we gain the knowledge to master the physics of 11 dimensions.
It may take a billion years to achieve that mastery. And there is no guarantee that we will make it: Kaku believes human civilisation is currently undergoing its most critical transition. If successful, we will make the transition to a Type 1 Civilisation: one that has acquired the ability to completely harness the energy of a sun, perhaps (as physicist Freeman Dyson has suggested), by enclosing it in a metal sphere. Then, we could go on to colonise the galaxy like characters of the Star Trek series, and beyond that to harness dark energy and travel through wormholes. But will we make the first critical transition given the rise of religious fundamentalism and a growing and pervasive anti-science? “We’re at the precipice,” says Kaku.
The musty, wood-panelled lobby of the hotel Rex in downtown San Francisco where we met is like something out of a 1930s Sherlock Holmes film set, evoking a bygone era of gentlemanly refinement laced with an edge of mystery. One bookcase boasted the Harvard Journal; in one corner, a parchment-like lampshade painted with Greek figures sat atop a handsome antique desk; club leather recliners made idle conversation with a table inlaid with a multi-coloured star design. Surreally, the surface of a large round table in the centre of the room was painted with an old clock face. As we talked, I could imagine a pipe-smoking Einstein sauntering from behind a bookcase to read the morning papers. It was a perfect venue for an elating journey into time and space, and leaving behind of everything that I had heretofore come to accept as reality.
With string theory offering answers to the creation of the universe, I asked Kaku why there was so little excitement from the public at large – in the way there was near hysteria surrounding Albert Einstein and relativity in his latter years, even though most people didn’t know what relativity was really all about. Indeed, Kaku rued the day that physicists passed up a golden opportunity to sell the revelatory potential of string theory. In the final days of the U.S. Congress’s deliberations on funding for the Superconducting Supercollider – a massive atom smasher that might have helped test elements of string theory – one of the last questions put to a physicist by a congressman was: will we find God? The physicist flubbed the answer, according to Kaku. “He should have said, ‘This machine will take us as close as humanly possible’. We learned a lesson from that: we have to engage the public.” The Supercollider was eventually cancelled in October 1993.
But if the average person hasn’t yet awakened to the powerful message of string theory and higher dimensions, the aficionados of the occult and science fiction certainly have. In 1854, a German mathematician by the name of Georg Bernhard Riemann proposed extra dimensions might exist in the real world.
He arrived at this view after imagining a flatworm living in a flat world. Here there would be no such thing as up or down: only side-to-side, front-and-back. But what if one day a wrinkle appears in the plane it normally inhabits? The worm will have no way of experiencing it. All the worm will know is that a barrier prevents its progress: some strange and invisible force. But Riemann then made the stunning extrapolation that perhaps the invisible forces encountered in our four dimensional world, like gravity, are also ripples in an unseen higher dimension. It was an idea rejected by scientists, but avidly taken up by members of the occult who divined that the extra dimensions must be the haunts of spirits. To visualise a higher dimension, devotees would stare for hours at a tesseract, a three dimensional cross that could – so the idea goes – be mentally folded into a fourth physical dimension in the same way that a flat cross will fold up into a cube. And in science fiction novels, tesseracts and multiple dimensions have long featured. Gratifyingly (for me) Kaku said that it is not actually possible to conceptualise a fourth spatial dimension.
Perhaps because of this, there are a few physicists (as well as engineers) who think that science fiction novels are precisely where string theory belongs. The size of strings, whose vibrations occur in 11 tiny, curled-up dimensions, are so miniscule – really, really miniscule – as to be immeasurable using current methods. The energy required to smash matter hard enough to break it up into strings would be akin to the energy released in the Big Bang – the one that created the universe – and therefore monumentally beyond what mere Earthlings could generate. Such a theory, untestable as it seems, riles many a scientist. Nobel Prize laureate Sheldon Glashow (now a professor of physics at Boston University) is a notorious detractor; he likens string theory to the AIDS virus – both infectious and incurable.
Kaku is unfazed. He says the early years of the new millennium may well be able to gather evidence supporting the existence of these, as yet, ghostly strings. In 2007, the Large Hadron Collider will be turned on. It is an atom smasher that is actually bigger than the nearby city of Geneva, being built at the European Particle Physics Laboratory (known as CERN) in Switzerland. After the demise of the Superconducting Supercollider, the Large Hadron Collider is the next best bet for probing the composition of matter. It won’t be able to detect strings themselves; but it will be able to detect their vibrations, potentially in the form of “sparticles” (Sparticles are theoretical ghostly partners of the fundamental particles – leptons, photons and quarks – that were produced in the Big Bang). “It won’t clinch it [string theory]. But string theory is the only theory that gives you sparticles.”
As for Kaku himself, he will not be one of those gathering the data. The way he works today is not all that different to what he did while he was dodging bullets in basic training, dreaming up mathematical equations. Except that his surroundings today are rather more tranquil. His typical working day is spent gazing out of his office window doing something akin to a musical composer, seeing and manipulating chunks of melodies in his head. But Kaku’s compositions are created from chunks of mathematical formulae. And he is striving for something that is no less than a cosmic symphony.
I floated out of the Hotel Rex as in a dream. It was like that moment in the movie Men in Black when Will Smith discovers that the National Inquirer – whose tabloid pages read like something out of a tawdry sci-fi pulp magazine – had been reporting the truth all along. I felt freed, no longer dragged down by the sordid parameters of existence: the inexorable passage of time, ageing, death, oblivion – there were other dimensions, parallel worlds, multiple universes beyond anything an engineer carp could imagine. I had become a convert to string theory and maybe even a believer in a God that composed the harmony of the Universe.
Kaku described his belief eloquently: “I would say that I lean toward the God of Einstein and Spinoza; that is, a God of harmony, simplicity and elegance, rather than a personal God who interferes in human affairs,” Kaku muses. “The universe is gorgeous, and it did not have to be that way. It could have been random, lifeless, ugly; but instead, is full of rich complexity and diversity.”