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Conquering the realm invisible

IMAGINE THAT THE MOST INTIMATE workings of the world around us were charted in a single sacred book, which, in a Greek myth fashion, the gods had denied mankind access to. We could gaze at the book on its shelf, but we couldn’t lift it, open it and leaf through its pages. Around it, there grew a white-clad priesthood who devoted their lives to unlocking the book’s secrets, but even they could never see beyond its spine. Then, one day, a father and son gave the priests a way to see inside the book and reveal the knowledge of the gods to all mankind...

Ok, that’s a little melodramatic but, in essence, it reflects the state of science at the start of the 20th century. The inner workings of the world were indeed locked away from the eyes of scientists – if it was too small to see with a microscope, it was beyond our reach. Then came what is probably the most important discovery you have never heard off.

One hundred years ago this week, a British physicist,William Henry Bragg, and his son, William Lawrence Bragg, found a way to look beyond the realm of the microscopic into the kingdom beneath of molecules and atoms and, in doing so, they unlocked the hidden mechanisms that drive the world in which we live.

The technique they discovered, called X-ray crystallography, allowed scientists to study materials at a molecular level by bombarding a crystalised sample with X-rays and then decoding the patterns left behind on photographic film – it enabled scientists to photograph atoms.

Using X-ray crystallography scientists could at last decipher the hidden molecular structures that govern how materials behave and even figure out how the atoms within them interact. Almost overnight, the Braggs’ discovery revolutionised the fields of physics, chemistry and biology and, almost exactly 50 years later it was used to unlock the DNA code of life and ushering the entirely new science of genetics.

There is virtually no part of our modern world - from biotechnology and pharmaceuticals to the planes we fly in and the fuels that run power our planet – that doesn’t owe something to X-ray crystallography.

You can see Hidden Structures’, a new display celebrating the centenary of X-ray crystallography, at the Science Museum, London

Note (a serious one this time): It might appear that plotting the electron gradient map is as simple as completing a join-the-dots puzzle. In reality, it involves taking the diffraction pattern and applying a complex set of mathematical equations, called Bragg's Law, which takes things like the angle of scattering and wavelengths and turns them into a sort of set of coordinates that can then be plotted as electron positions... just thinking about it makes my brain hurt.