20/03/2019

Column in Folha: What is the purpose of Einstein's science?

Fonte: Science & Society Picture Library/Getty Images

Reproduction of Marcelo Viana's column in Folha de S.Paulo.

It was Albert Einstein's "miracle year." In 1905, the 26-year-old physicist published, in addition to his doctoral thesis ("On a new determination of molecular dimensions"), four outstanding papers on very different topics.

At the time, Einstein worked as a patent analyst: research was a kind of "hobby." His goal was to understand the mysteries that surround us, without any concern for the usefulness of his discoveries. However, they revolutionized the way we live today.

The first work, "A Heuristic Viewpoint on the Production and Transformation of Light," explained why electric current is created when metallic surfaces are illuminated. This phenomenon, called the photoelectric effect, had been observed by the Frenchman Alexandre-Edmond Becquerel in 1839, and confirmed by the German Heinrich Heinz in 1887.

Einstein proposed that light is made up of particles called photons. Electric current would result from photons colliding with electrons and releasing them from their positions within the atoms of a metal. This theory was experimentally confirmed and earned Einstein his (only) Nobel Prize, in physics, in 1921. Applications are everywhere: photoelectric cells, remote controls for devices, presence sensors, photocopiers, digital cameras, and much more.

In 1827, the Scottish botanist Robert Brown observed that pollen particles suspended in water are constantly agitated, as if they were alive. The first satisfactory explanation was given by Einstein, also in 1905, in his work "On the motion of small particles suspended in a stationary liquid". The French experimentalist Jean-Baptiste Perrin confirmed this explanation and won the Nobel Prize in Physics in 1926. Real-life applications range from the mathematical modeling of the financial market (stock exchange) to the development of advanced decision-making algorithms.

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