Getting a new perspective; Michio Kaku was inspired by watching fish in a pond

Credit: Chris Callas/COSMOS

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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 laurette 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."