The imaginary number takes mathematics to another
dimension. It was discovered in sixteenth century Italy at a
time when being a mathematician was akin to being a modern day
rock star, when there was 'nuff respect' to be had from
solving a particularly 'wicked' equation. And the wicked
equation of the day went like this: "If the square root of +1
is both +1 and -1, then what is the square root of -1?"
Previously, mathematicians had rolled their eyes skyward
and prayed for divine intervention. But where others failed,
the creative Italian Rafaello Bombelli triumphed with his
invention of the imaginary number. The imaginary number is the
square root of -1 and is known as 'i'.
Imaginary
numbers are real numbers multiplied by i. If, like many, you
find yourself saying "but what's the point?" then think on
this. Imagine a world without electric circuits. No circuits,
so no computers. No computers, so you wouldn't be reading this
now. And while engineers need the imaginary number to analyse
electrical waves, physicists need it to calculate the
fundamental forces that govern our Universe via quantum
mechanics.
And, most bizarrely of all, time might have an imaginary
dimension, which might explain how time started. The Big Bang
gave birth to our Universe some 15 billion years ago. It was
every mother's dream birth, taking less than a second for all
time, matter and energy to be born, with no need for an
epidural. But if the Big Bang marks the beginning of time and
the beginning of matter, what was there before it? How could
time just start?
Einstein's classical general theory
of relativity linked together time with the three spatial
dimensions we are all familiar with (up - down, left - right,
and in - out), creating a four dimensional 'space-time' in
which time can move forwards only. A brilliant theory, but one
that comes a cropper when applied to the creation of the
Universe.
But invoke quantum theory and a dollop of
imaginary time and things begin to make sense ... at least to
cosmologists. Imaginary time is measured in imaginary numbers
and unlike real time, it can move backwards and forwards like
an extra spatial dimension. Apparently, this gives the Big
Bang something to start from.
