Outside Our Everyday World
Hiromi Eba, Associate Professor
Faculty of Engineering, Tokyo City University
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I don’t know if our Creator said “Let there be light” or if light and the universe were born out of the Big Bang, but I do know that the sun rises in the morning and we turn on our electric lights at night. I do know that now is the Age of LEDs and that lights light up our world. When light strikes physical objects and scatters, it stimulates one of our five senses, sight, and enables us to understand the world around us.
Even though we take the existence of light for granted, people can only detect the visible part of light with their eyes. But there are other types of light that are invisible, such as X-rays. The term X-ray was tentatively applied to a mysterious light discovered by Wilhelm Conrad Röntgen in 1895 because the ‘X’ signifies an unknown number. It was only through the impact of the radiographic images it produced, and the medical and engineering utility it offered, that the names X-ray and Röntgen became famous everywhere. In addition to their ability to see through things, X-rays have other useful applications that employ absorption and scattering effects and that are not widely known.
I first learned about X-ray analysis when I entered university, and since then I have spent my life in the observation of materials using X-rays. The difference between X-rays and visible light is wavelength. The wavelength of visible light ranges between 360 and 830 nm, while that of X-rays ranges between 0.01 and a few tens of nanometers, which are very short wavelengths. Observation of materials with X-rays enables us to see much smaller objects than is possible using visible light and our sense of sight. X-rays provide us with information on how the molecules and atoms of matter align themselves, and information on the electrons in those particles. X-rays then allow us to go beyond our everyday world and step into a different microscopic world. This is the reason why X-rays continue to fascinate me.
Despite being a different world, the world we live in and the world of molecules and atoms are connected. In the field of physics, classical mechanics talks about the universe and the earth. There is another type of mechanics though, which talks about the world of molecules, atoms and even electrons. This is called quantum mechanics and through the correspondence principle, it can also be applied to our world. Light is treated in physics as one part of electromagnetic waves, which consist of radio waves, microwaves, infrared waves, visible light, ultraviolet waves, X-rays and gamma waves. The names of the waves change as the wavelengths become shorter, but they are all nevertheless the same type of wave. Although we live in an infinitesimally small part of these waves in this expanding space and time, we want to peek at the outside world extending away from our own world.
Of course, there were many things other than X-ray analysis that I encountered at university. One that I have clear memories of are calipers. Calipers are one type of ruler. Rulers have been by my side from the days of my earliest memories. Measuring my own height year by year, checking the length of things around me, rulers have been a natural part of my life that I used for measuring the size of everything in the world in which I lived. Then came calipers, which attracted me with the semi dull luster and weight of the metal, and the robust yet delicate workmanship that does not permit even the smallest of distortion. Calipers might not have much use in a chemistry laboratory, but I did buy my own set when I got a job as a researcher. I keep them in my desk drawer with my stationery.
I shouldn’t need to explain, but the difference between a ruler and calipers lies in their precision. Compared to our sense of touch, another of our five senses, they provide much greater precision and accuracy. They lead us into another dimension, another microscopic world that lies just beyond our own world of senses. When measuring, evaluating, designing or machining, they bring forth creativity on a qualitatively different scale. I suppose the true appeal calipers have for me is that while they are a useful and simple tool that you can carry and have on hand when needed, they also represent a doorway to another world extending away from our everyday world.
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