A few days ago, the occupier on the fourth floor of the facing building and the one in which I live, changed the living room light bulb. In the evening, when switching on the light, the window lights up a striking white and cold color which clashes with neighboring rooms. The old incandescent bulb was replaced with a new energy-saving light bulb, hence, its fluorescence. This is owing to the fact that the European Union has decided to progressively ban the manufacture of incandescent bulbs, which began in 2008. Developed over the late 1800s (patent for the incandescent bulb with tungsten filament was filed in 1890), they dominated the entire past century with their warm light which was pleasant on the eye, because, quite similar to the sun's light, it has a huge defect: the extremely low efficiency.

With incandescent bulbs, the filament is heated up – owing to the Joule effect – by the electrical current which passes and reaches a temperature of 2,700 K (at higher temperatures, the filament would start to sublimate and at 3,700 K, the tungsten would melt). As with all hot units, the filament emits electromagnetic radiation with continuous spectrum (similar to a spectrum of black matter). At a temperature of 2,700 K, the emission peak is near to infrared, with a wavelength of 1 μ, and only approximately 5% of that emitted is “visible” light. In comparison, the solar emission peak is at approximately half a micron, well within the visible range, with the Sun's surface temperature at 5,700 K. Hence, the reason for the low efficiency of incandescent lamps, which release 95% of the energy absorbed as heat. The replacement florescent bulbs, have been available for over seventy years, however it is only over the last decade or so, that they have been produced in extremely compact shapes and with the same connection as the incandescent light bulbs, which makes them easy to use without having to adapt the lamp socket or chandelier. Those who have purchased them already know that, with the same light output, they use a quarter or a fifth of the energy used by incandescent bulbs. However, the light they emit (owing to the disexcitation of atoms which cover the internal surface of the bulb, and therefore concentrated across the wavelength, that characteristic of the fluorescent material used) is not particularly pleasant on the eye, which is accustomed to the continuous spectrum of the sun's light. New light production devices were developed just recently and acronyms like LED (light-emitting diode) and AMOLED (active-matrix organic light-emitting diode) are increasingly used, just like the multiple applications overseen by these same devices, which are extremely versatile. TVs, the screens of many smartphones, cluster light bulbs and a whole host of other contraptions use this new lighting technology.

In almost all cases, new technologies quickly work on the significant improvements of one or more elements when compared to the previous versions. The new elements are accepted because they are more compact, or faster, or more capacious, cheaper, safer. During my short professional life – not even forty years have passed since I graduated – I have witnessed impressive technological changes and adjustment which serve as proof of how quickly the very things we are familiar with expand as do applications based on new knowledge, affecting our everyday lives. The electronic calculus has probably seen the fastest and most radical changes. I remember that you were taught to use the standard calculator in your first year of university. Small and portable (some were as small as 25 cm, some even smaller, which could be placed in a coat pocket), it enabled you to carry out calculations at a much faster rate than when using paper and pencil. Based upon the property of the logarithm it became standard in the 17th Century and quickly disappeared at the beginning of the 70s of last century with the appearance of the first electronic hand-held calculators: the legendary HP35 represents the founder. During my test work, the main tool used to give instructions to a computer (at the time, they were called mainframe and were housed in specific rooms, with lever air-conditioning to dissolve the heat they produced and raised flooring for the cables to flow underneath) were punched cards, One instruction, one card. They were punched using large machines like a writing desk. Already, as early as the first years, just after graduating, first news tickers and then video display terminals served the input/output functions in much simpler fashion. Moving on to more modern calculators, we can also speak of the much greater calculation ability which is over a million times greater than that in the 70s – and, primarily, it is widespread, not just in work places but also in homes and, even, in the schoolbags of the majority of students. I wrote my degree dissertation using a typewriter. Fortunately, photocopiers were relatively known, at least, within universities and research institutes and I could therefore avoid using carbon paper. On the other hand, there were still no methods available for writing Greek letters or mathematical symbols, which would inevitably appear in a physics test. I left a space and wrote the necessary part by hand. A revolution arrived when the IBM typewriters became available with mobile and interchangeable heads. You could assemble the one producing Greek symbols and you were ready to go! When the typewriters went electric, they came with a memory and the possibility of correcting errors which beforehand, necessitated the use of the “typewriter rubber”. I remember how enthusiastically the first word processors were received followed by the perfection which could be achieved with the TEX program. During the next few years conducting my research activity, I was in England and I painstakingly worked with some colleagues in Australia. Owing to the time difference, the relative costs, communication over the telephone was limited, which at the very least, was essential. So, information was passed on via post and, in the case of emergencies, via brief messages which were codified on a strip of perforated paper, and sent via telefax. The fax machine, a marvelous reality which enabled the immediate transmission of pages of text and images, had not yet caught on. Presently, although largely used, the fax machine is on the path of obsolescence, replaced by Internet transmissions. Such great emotion when after a few years passed (I was already in the United States) I oversaw, on my PC monitor, the node to node transfer of an email message sent in Italy via DECNET.

My first astronomical observation took place using the Isaac Newton Group of telescope (ING), a telescopic with a primary mirror with a diameter of 2.5 m, which, at the time, was housed in England at the Royal Greenwich Observatory (RGO) in Sussex (the RGO was transferred to Cambridge first in 1990, and then shut down in 1998; the ING telescope is till in operation on the island of La Palma, in the Canaries, just a few hundred meters from our Telescopio Nazionale Galileo).
At the time, the images (and spectrums) were saved as exposed photographic emulsions on glass strips which necessitated development and drying in a darkroom. Just a few years later, CCDs became known and with their 80%+ efficiency enabled the increase of a factor of 10 and over, of the details of observations, dependent on the size of the telescope used. These same CCDs which currently replace the film of cameras, which have changed and become smaller, have become ubique, and are even inserted in almost every mobile telephone.

My generation was born in the analog era. As children, we would do our sums using paper and pencil, we sent letters with stamps, we used Kodak 24 din film cameras when taking photographs, we listened to music on the radio and watched films, but only at the cinema or when they were shown on TV. Encyclopedia took up one or two shelves on the bookcase and consulting them represented a task, even a physical one. The largest optic telescope in the world was the legendary 5 m telescope of Palomar Mountain. Gradually, we became digitalized, experiencing this transition across all fields: calculation, text, music, images, communication. A revolution. Telescope mirrors have reached diameters of 10 m (and they are creating one of 30 m and larger) and it is no longer necessary to turn up in person at the Observatories to be able to use them. In the case of VLT in Paranal Mountain, for example, the data is gathered by ESO staff and we withdraw it from the archives with just a few clicks of the mouse. I am convinced that technological innovation and broadening of knowledge represent a continuous revolution. Every generation is proof of period changes, time passes according to a log scale and every time period corresponds to multiple knowledge developments. My daughter is just about to start her last year of her degree course. Just like all her peers, she was born digital and being able to have instant access to all-encompassing information comes naturally to her. We are moving towards a society where knowing how to find becomes the most important thing, to the detriment of the importance of knowing. When I think about the amazement and incredulity my great-grandmother, who lived in the countryside not even a century ago, would demonstrate when faced with all you can do with an iPad, I am envious of my great grandchildren who will see the end of the century and experience all sorts of wonders. I am not thinking about computers able to receive direct input from our thoughts nor the regeneration possibilities offered by the mastery of stem cells.

These (amongst others) are wonders on which we are currently working and so they are not difficult to imagine.
Instead, I am fascinated by that which I am unable to imagine.

Extracted from: Le Stelle no. 109, August 2012