One night in December 1986, Lisa Belkin, a reporter for The New York Times, was trying to cure a cold when the phone rang. On the other side of the line, a friend invited her to go to the cinema. Lisa hesitated, but her friend insisted. The programme was only a pretext for her to hook up with a colleague and the journalist would have the task of distracting a friend whom the boy would bring to the meeting. Lisa got into a sweater and went to meet her, but when she arrived she learned that her pair had been replaced by another guest, a resident doctor who had just left the shift. During the session, the journalist and the doctor, exhausted after 36 hours of work, slept. Four months later, however, the two were married and to this day live together.

The case was described by Lisa herself in a report on coincidences that allegedly surrounded the September 11^th, 2001 attacks. The text divided opinions. What, after all, would have moved the facts that night and led the journalist to yield to her friend’s pressure, despite the adverse conditions, in a kind of conspiracy to change her life? Squire Rushnell, a spiritualist and author of When God Winks: How The Power of Coincidence Guides Your Life, saw a mystical force behind every detail of the story. For statistician Persi Diaconis, of Stanford University, in the United States, it was all an event explained by mathematics. “The law of large numbers demonstrates that in a vast environment, like the world, things are always happening, even strange things”, Diaconis says. “It would be abnormal the day that something unexpected did not happen.” Sceptical, Lisa agrees with him.

It has always been like this. Coincidences happen everywhere and with everyone. (Who has never been surprised to remember someone who is distant and then receive a call from the person?) But when they do happen, the controversy is in the air between those who prefer the rational argument, based on probabilistic calculations, and those who adopt the religious justification that nothing happens by chance. The novelty is that a recent strand of scientific research may be about to break this dichotomy. In this new perspective, coincidences are part of a broad and universal phenomenon, whose entrails guard the secrets of the very functionality of the cosmos: the phenomenon of synchrony.

Against some theories and even the laws of thermodynamics — which suggest the relentless degeneration of nature in a state of great disorder —, the study of synchrony suggests a more harmonious and cooperative universe than we ever imagined. A place where all the parts — from atoms to galaxies, from bacteria to humans — dance in partnership, under the command of a collective and spontaneous order. “The entire Universe seems to carry the seeds of its ordination”, says Steven Strogatz, a mathematician at Cornell University, in the United States, and a pioneer of what has been labelled the science of synchronicity.

Last semester, Strogatz published the book Sync — The Emerging Science of Spontaneous Order, which summarises the history and purpose of the new field of study, comments theories and models already envisaged and provides for the application of synchrony in areas as diverse as traffic jams, financial market oscillations and the prevention of genetic diseases. “This is the future of science, the way to answer the greatest and eternal questions”, the author says.

The panorama presented in Strogatz’s book is impressive, but it is probable and realistic, according to the physics PhD Murilo Baptista, from the area of dynamic systems of the Institute of Physics of the University of São Paulo. “Since there are no isolated systems in nature and synchronicity can also occur in very weak interactions, it is expected that the phenomenon of synchrony is really frequent”, says Baptista. The central idea is that the synchronisation between interacting systems describes the emergence of a collective order, to the point that the observation of only one system leads to the knowledge of the state of the whole set. Understanding synchronisms can be the means of explaining an infinity of natural behaviours.

The investigation of synchronous systems is recent and multidisciplinary, but the phenomenon of synchrony has been known since the 17^th century. In 1665, Dutch physicist Christiaan Huygens was in bed, sick, when he realised that, regardless of the initial state of each, the pendulums of two clocks that he had built soon adopted the same rhythm, one moving to the left and the other to the right. Surprised, Huygens attributed the phenomenon to a pulsation transmitted through the wooden beam that held the clocks, but no one believed him. His reasoning would only be salvaged in the 1960s by American biologist Arthur Winfree, who at the time experimented with paired oscillators — machines of repetitive behaviour, such as pendulums, used in the simulation of synchronised systems.

In addition to the experience with machines, more accurate than Huygens’ clocks, Winfree studied the synchronism of living beings from the firefly show in Southeast Asia, who in the thousands usually blink in unison on the riparian shores. The phenomenon begins with each insect emitting flashes at its own pace. An hour later there are synchronisation pockets that expand, forming a cloud of fireflies blinking as if they were a single gigantic insect. How does this happen? Winfree discovered that the flashing of the firefly is a signal that encourages the neighbour to reprogram their own flash frequency, adjusting it to the rhythm of their companion. Having synchronised a pair, the effect spreads across the rest of the group. Whether in a bunch of fireflies or in other types of systems, synchronisation only occurs when the signals exchanged by the individuals exceed the initial frequency of one or the other, causing the ‘reprogramming’ of the cycles of the influenced individual.

“Under this framework, anarchy predominates. Above it, a collective rhythm is established”, wrote Winfree, who died last year.

Mathematical models for synchrony were established by Japanese physicist Yoshiki Kuramoto and also by Strogatz, while studying the working of Josephson junctions, a superconducting device that yielded the 1973 Nobel Prize in physics to Englishman Brian Josephson, a scholar of synchronisation. A Josephson junction is such a fine oxide film that, sandwiched between metal conductors, can be traversed by the electric current, permitting flow oscillations exceeding 100 billion cycles per second – 50 times more than in the fastest home computer. That is, contrary to classical physics, an insulator (oxide) becomes a superconductor, a fact that is possible because, in a row of junctions, the electrons synchronise and form a condensate that does not find resistance.

“Synchrony manifests from the subatomic to the macrocosm, on frequency scales ranging from billions of oscillations per second to just one cycle in 1 million years”, Strogatz says. The movement of the Moon around the Earth is synchronous, but the Earth-Moon synchronicity, of periodic and stable behaviour, is not the same as chaotic systems. In the latter, synchrony preserves the chaotic behaviour of each element, which, in turn, presents a singular complexity. In traffic, for example, each car has its complexity, but also interacts with other vehicles, influenced by factors such as traffic rules and traffic lights. If we can equate these factors, according to Baptista, it will be possible to put the vehicles in synchrony, causing congested traffic to behave like intense traffic, but flowing satisfactorily.

Even greater challenge is to establish a theory of synchronicity in human events. Many researchers fail in this attempt, according to Strogatz, because their models underestimate man’s characteristic volition and expect him to act like a robot. The evidence of human synchrony, however, leaps from recent studies and from the common observation of everyday life. Anyone who has travelled with a large group of women probably learned that a good number of them menstruated suddenly, almost at the same time. The harmonisation of rhythm in this case would be the result of a ‘chemical communication’ between women through pheromones, the same type of hormone, perceived by smell, that works on sexual attraction. Synchrony would also be behind events such as fashion and collective manifestations – from audience applause to street clashes – and above all the functioning of the brain and genes.

Researchers Nancy Kopell and Jim Collins, of the University of Boston, in the United States, are currently trying to implant in the bacterium Escherichia coli a mechanism capable of turning on and off genes from the unicellular organism at certain intervals and thus programming the synthesis of certain proteins. The success of the experiment will help understand the synchronism that may be responsible for the functioning of human genes — an important step in disease prevention and the manufacture of cell synchronising regulatory drugs. As for brain synchronisation, there are stronger indications. “Although scientists are still struggling to understand the neural basis of thoughts and feelings”, Strogatz says, “studies by neurobiologists attest that cognitive acts are linked to synchronous waves of neurons.”

An insight would be like a synchronous electrical burst, an instant in which separate parts of the brain come into harmony. The clarification of this kind of synchrony may lead, perhaps, to the solution of the enigma of consciousness and the prevention of disorders such as epilepsy. And also to the understanding of the coincidences of the day-to-day life.

How can we explain, after all, a story such as that experienced by engineers Luciano Bezerra de Melo and Garibaldi Freitas a few years ago in China? On a trip to Hong Kong, during a circus show, the two commented that it would be impressive if they found someone there from Natal, the Brazilian city where they live. Minutes later, they heard someone shout, “Garibaldi!”. It was a friend who had lived in Natal and was travelling on business. A mathematics scholar, Melo says he has never found a justification for the case, which now seems to him explicable by synchrony. “The coincidence of events can be interpreted as a consequence of the synchronicity between the elements of a network of interconnected people, society itself”, says Baptista.

As in the case of flashes of fireflies and pheromones, coincidences would occur on the basis of a physical communication between the parts, although not noticeable on a macro scale. A synchrony between elements at the atomic and subatomic levels whose effects, as important as the electron harmony in superconductivity, would be reflected mainly in brain activity. How this alleged communication occurs is an unknown, although experiments and equations of quantum mechanics indicate the occurrence of a non-local (outside of space-time) type of communication between subatomic particles. This is the case of the experience of the 1960s by British physicist J. S. Bell with a pair of photons (elementary particles of light) correlated and sent in different directions. Even from a distance, an event that affected one of the photons also hit the other.

Many students of synchronism consider this a possible explanation for chance. So the next time a coincidence happens, don’t be surprised. You probably worked for it to happen.

To learn more

Books

Sync – The Emerging Science of Spontaneous Order, Steven Strogatz, Theia, New York, 2003

How Nature Works: The Science of Self-organized Criticality, Per Bak, Copernicus Books, New York, 1999

Internet

www.tcm.phy.cam.ac.uk/~bdj10