Imagine, the year is 1905. One day, the clock on the
tower in Berne, Switzerland, is a little late. Two minutes late, to be more
precise. For that reason, a man who
lives near the tower does not wake up at the same time
that he usually wakes up to go to work. Realising the mistake, he
becomes a little nervous. It takes him a little longer to get dressed, drink some
coffee and leave the house. He leaves five minutes later
than usual. He is about to cross the street. Meanwhile, a banker gets
into his new car without knowing that it has a
problem with the brakes. Our man crosses the street
and doesn't see the car. The man is run over and dies. This man is no less than
Albert Einstein. That year Einstein should
have published four works that would become the basis
of modern physics. Innovations like GPS, TV
screens, the semiconductors that allowed us to create
laptops, never happen. The computer, the laptop, the
mobile you are watching this video on never come into
existence. And this video... doesn't exist
either. This sequence of events is an
example of what is known as the butterfly effect, a manifestation of Chaos
Theory. For many centuries, the world
was explained through the laws of Isaac Newton and
classical physics. According to these laws, if the current state of an object
is known, its future behaviour can be predicted with
relative ease. Chaos Theory questions this
deterministic vision: not everything is predictable
anymore, nor does it work like clockwork. Since the 1800s, mathematicians have raised
the idea that not all phenomena could be
predicted by Newtonian laws. But a meteorologist named
Edward Lorenz made chaos theory a visible phenomenon. It all started in 1961 when he
was working on a mathematical model to
forecast the weather. Lorenz entered data such as
temperature, humidity, pressure, and wind direction
into his computer. His computer would draw a
graph modelling what the weather would be like, not always accurate, but very
close to reality. One morning, Lorenz decided
to verify some results. He stopped the computer, to
save time, entered the numbers himself, and went to
grab a coffee. When he returned, the chart
was incredibly different from the original. At the beginning it started out pretty similar, but in the
middle it presented a completely different
trajectory. Surprised, he checked the
numbers. He found that the number he
had entered was three tenths less than the number used by
the computer. That difference, which altered the trajectory so
much, is equivalent to a particle of dust on the Eiffel
Tower, or one less feather in the weight of a duck. Lorenz deduced that this
experiment was not a special case, that there were other
systems in which tiny differences produced, over
time, monumental changes, making everything seem unpredictable... that the
flapping of a butterfly in Brazil could, in theory, cause enough of a disturbance to
spark a tornado in Texas. Even though we have a good
idea of how the universe works, there are no measurements that allow us
to determine the exact position and speed of every
atom in the universe. And this "inaccuracy" in our calculations makes
predictions difficult, one of the reasons why long-term prediction is impossible. But chaos is not the same as
disorder. Although chaos makes
predictions difficult, the universe is not random
and effects still follow causes. And no matter how chaotic it
may seem, a system always follows a trajectory towards a
certain point. For example, in the
calculations Lorenz used for his model, the
trajectory created a pattern that
resembled the wings of a butterfly. Understanding these patterns of chaos has practical
applications. In the stock market it
reminds us that a slight fluctuation can cause a
crisis in the market
- and that is
why we cannot speak of predictions but of
probabilities. In the human body, it allows us to understand the chaotic behaviour of a heart with cardiac arrhythmia. Even in human behaviour, the
butterfly effect can be used to analyse social phenomena.
For example, how trolling on social networks can be triggered
by a single negative comment. Our universe continues to
obey the laws of cause and effect. The sun will continue to rise
every morning. The planes we build will keep
flying. Ultimately, chaos theory
introduces an element of uncertainty into our reading
of the Universe. It reveals the limit of our
knowledge.