Simon Singh, author of a new book about the Big Bang, explains why a picture is worth a thousand words.
Perhaps it is because I worked as a film-maker before I became a writer, or perhaps it is just because my words are inadequate. Either way, ever since I started writing science books I have relied heavily on the use of photographs to illustrate my prose.
In fact, in my latest book, Big Bang, I have possibly gone too far. For example, the book contains a dozen photographs of Fred Hoyle, and he did not even believe in the Big Bang. Nevertheless, I think I can justify each and every image.
SIR FRED HOYLE
For example, this picture shows Fred Hoyle as a young boy, at an age when he was regularly playing truant from school.
It is easy to relate a few anecdotes about the rebellious young Hoyle, but this snapshot shows Hoyle with his cheeky grin and confident pose, capturing all the characteristics that would later turn him into a cosmologist who would relentlessly question orthodoxy.
This included criticising the Big Bang theory of the universe.
And, of course, it is also necessary to show Hoyle at the peak of his career, surrounded by his equations, having developed his own theory of the Universe.
A scientist in front of a blackboard might be a slightly clichéd image, but the Hoyle archive contains a unique series of photographs taken while Hoyle was in the middle of working through some calculations with his colleague, Jayant Narlikar.
The images capture the mood of cosmologists at work, something that I would struggle to achieve with mere words.
My favourite image of a scientist in front of a blackboard concerns Georges Lemaître, the Belgian cosmologist who proposed the idea of a Big Bang. In 1920, after graduating in theoretical physics, Lemaître enrolled in a seminary at Maline.
He was ordained a priest in 1923 and throughout the rest of his life he maintained parallel careers as a physicist and a priest.
He said: "There were two ways of arriving at the truth. I decided to follow them both."
Lemaître did not use the expression Big Bang for this theory of cosmic creation, but instead he talked of 'a day without a yesterday'. The scientific establishment rejected Lemaître's theory, preferring instead the notion of an eternal Universe.
Part of the reason for criticising the Big Bang theory was that it involved a moment of creation, which raised awkward questions such as who or what created the Universe? Hence, mainstream scientists were suspicious that this supposedly scientific theory of creation was the result of a religiously biased agenda.
In fact, Lemaître tried to be as objective as possible and tried to divorce his scientific research from his Christian beliefs. Throughout his life he had to tread the fine line between his calling as a priest and his passion as a cosmologist.
Nothing illustrates this as clearly as the image of Lemaître wearing his dog collar with a backdrop of mathematical equations.
PENZIAS AND WILSON
As well as capturing the characters of scientists, images are also important for showing their apparatus.
This famous image from the 1960s shows Arno Penzias and Robert Wilson in front of their giant radio antenna, which first detected the radio echo from the Big Bang.
Because most of us think of a radio antenna as a short stick of metal, it is important to have an image of the sort of exaggerated antenna employed by radio astronomers.
This radio echo from the Big Bang was measured in finer detail by the Cobe satellite in 1992. This allowed astronomers to prove that the Universe contained variations in density when it was just a few hundred thousand years old. These variations were critical because they acted as seeds for the formation of the galaxies.
Stephen Hawking called it "the discovery of the century, if not of all time", because it provided further proof of the Big Bang theory of the Universe.
COSMIC BACKGROUND EXPLORER (COBE)
The Cobe team represented their measurements in terms of a map, which consisted of an eye-catching mix of pinks, mauves and blues.
This particular image proved without any doubt the absolute importance of images in the communication of science, because it was splashed on the front pages of newspapers around the world when the Cobe result was announced.
At first sight it might have seemed that the patches of colour indicated the density variations in the early Universe, but in fact the scientific interpretation was not as simple as this. The variations could only be identified by a deep statistical analysis, and virtually nothing could be ascertained by mere visual inspection.
Hence, it could be argued that the image was misleading, or that it was nothing more than a publicity stunt. However, the pinky-blue blotches were genuine measurements, and more importantly they helped to convey the highly arcane concept of variations in a radio echo from a Big Bang that happened billions of years ago.
The journalists and their readers needed something that they could relate to. Consequently, the Cobe map has become one of the most famous images in the history of cosmology.
Big Bang by Simon Singh is published this month by Fourth Estate.