Other Anniversaries celebrated during the International Year of Light 2015

Abstract

As we all no doubt know 2015 has been chosen to be “The International Year of Light and Light-based Technologies” because the anniversaries of a series of outstanding achievements in the history of the science of light are commemorated this year. One thousand years ago, in 1015, Alhazen published his works on optics. Two hundred years ago, in 1815, Fresnel proposed his notion of light as a wave and in 1865 Maxwell developed the electromagnetic theory of light, thereby unifying light, electricity and magnetism through “Maxwell’s synthesis”. Einstein explained the photoelectric effect in terms of quanta of light in 1905 and a century ago, in 1915, light was embedded in cosmology through his general relativity theory. Fifty years ago in 1965, Penzias and Wilson discovered the cosmic microwave background, an echo of the origin of the universe and evidence of the Big Bang, while 1965 was also the year of Kao’s achievements concerning the transmission of light in optic fibres, which formed the basis of today’s ubiquitous optical communication. However, there are many other achievements related to light and its technologies, perhaps not as important as those above but which are also worthy of mention. With this in mind I decided to write this article. My first thought was to find other important achievements in the science and technology of light in the same years: 1015, 1815, 1865, 1905, 1915 and 1965. However, I immediately ruled out 1015 and chose the year 1665 instead, that is 350 years ago. In the case of 1965, I also set out to find two achievements similar to those mentioned above: an accidental discovery like the cosmic microwave background and a technological achievement like optical fibres. Below is my list of these “other anniversaries”.