Mountain climber, painter, and most importantly, a genius physicist. Simultaneously with Albert Einstein, he explained the phenomenon called the Brownian motion, used in economics and new technologies. This September, one hundred years after his death, Kraków institutions are celebrating the main events related to Marian Smoluchowski Year.
Why is Prof. Marian Smoluchowski widely considered to be one of the most important physicists of the late 1800s and early 1900s? What did he study? Where did he work? Why does a lot of members of the scientific community believe his discoveries are worthy of a Nobel Prize? Marian Smoluchowski Year is a great opportunity to discuss this great scholar’s life and learn more about his work; even more so because most of us don’t even realise how much his research affects our daily lives.
Marian Smoluchowski Year:
Events in Kraków
The deeds of great men tend to be recognised and appreciated after their death. This can’t be said about Marian Smoluchowski. He was an esteemed physicist, travelling around Europe, seeking and sharing knowledge. If we compiled a list of his mailing addresses, we’d find it comprised the most important European cities. He was raised in Vienna, where he earned his PhD. He studied in Kraków, Warsaw, and Cambridge. He had strong ties to the Jagiellonian University: he worked at the Chair in Experimental Physics, and in July 1917, he was elected the rector of the university. Throughout his life, he had the opportunity to draw inspiration from other important scientists, like Lipmann, Kelvin, and Einstein. Perhaps the only fault that Smoluchowski would be able to find in his life is that it was a short one: he died on 5 September 1917, at the age of 45. His death stirred his family and friends, but also the scientific community. Albert Einstein wrote that even though fate put an end to Smoluchowski’s noble work as a researcher and tutor, we should strive to follow his example in our lives. This respect didn’t come from nowhere. Although separately, both Smoluchowski and Einstein explained the phenomenon now known as the Brownian motion, largely unknown at the time.
Surprisingly, the Brownian motion isn’t named after the person who explained it, but rather by the person who first observed it. Robert Brown was a botanist. While looking at pollen through a microscope, he found out that when submerged in water, the individual pollen grains are in constant chaotic movement. Biologists trying to explain this falsely assumed everything that moves is alive. This theory was quickly debunked when an inorganic substance was used instead of pollen, yielding the same results. So what caused the movement? In 1877, almost 20 years after Brown’s death, Joseph Delsaulx suggested it was caused by the thermal movements of water. It wasn’t until the 20th century that the chaotic motions of pollen were described mathematically.
Things such as pollen in water or molecules of fat in milk can be viewed as particles which always ‘change their mind’ immediately after choosing a direction. Today, this ‘indecisiveness’ can be easily explained by basic physics. Matter is built out of atoms, and the atoms are always on the move. So instead of thinking of the pollen grain as static, we need to imagine much smaller water particles swarming around it and pushing it in different directions. The grain moves in the direction in which the most force is applied. It’s worthy of note that the difference in size between a single grain of pollen and a water particle is so vast that if we enlarged the latter to the size of an eye of a needle, the former would have a diameter of a metre!
Einstein and Smoluchowski rose up to the task of answering the question asked nearly one hundred years before. Unknowingly, Smoluchowski published his explanation in a scientific journal one year after Einstein did. It appears he was late. Why, then, is he so respected in the academic world? It would seem that replicating the results of Einstein’s study isn’t that big of a deal. The reason is the method Smoluchowski applied in solving the problem. Its advantage over Einstein’s is that the issue was tackled with in a microscale. Smoluchowski proved that the motion of particles is related to Avogadro constant and the liquid’s temperature. His work also convinced the remaining sceptics to finally accept the existence of atoms.
Coming back to the ‘indecisive’ pollen grains: as we’ve established, the difference in size between them and water particles is so big that individual pushes are not enough to move them – the pollen grain will only move in a certain direction after enough water particles push it that way. Smoluchowski concluded that it was pointless to try to observe only one water particle. Instead, he applied the probability theory to account for all of them and predicted the movement of the pollen grain.
IoT vs. the Brownian motion
As it turns out, these predictions are useful not only to explain the Brownian motion. Small, subtle changes can indicate a general tendency. The method turns out to be so universally applicable that it was quickly adopted in other scientific fields, e.g. economics – the asymmetrical Brownian motion is used to describe the stock market. A single share is treated like the grain of pollen, and inquiries and offers are the particles that swarm around it.
Today, this method allows us to realistically think about the Internet of Things. It’s a concept according to which common appliances in our houses will soon be connected to the Internet, thereby making them easier for us to control. For example, a smart toaster will prepare crunchy bread for us before we even get out of bed. It’s estimated that by 2020, 30 to 50 billion devices will be connected to the Internet. This is hardly surprising, since smartwatches and smart refrigerators are already in sale. In a certain way, this concept bears a striking resemblance to the Brownian motion: a single device doesn’t make much of a difference, but 50 billion certainly do. How are we going to manage such a complex system? The answer lies in the work of Smoluchowski and his successors.
Original text: www.nauka.uj.edu.pl