In search of the frontiers of knowledge
After school, there was often no stopping the young Kai: after lunch and the tiresome homework that had to be done, the 14-year-old boy usually had only one destination – the Wilhelm Foerster Observatory in the Steglitz district of Berlin. A few years earlier, his grandparents had sparked in him an unbridled enthusiasm for planets, stars and the universe with the gift of a book from the “Was ist was” series of science books for children. For hours – and usually well into the night – Kai watched waxing moons, bright fixed stars, Venus and the sun. But one evening disaster struck. He had come home much later than his parents had stipulated – with dramatic consequences for the boy: from then on, he had to be home by 10.30 pm. But the despairing Kai Schmitz was clever and knew how to help himself in his own personal emergency: he started up a petition on his own behalf. As many as eleven friends and acquaintances wrote in favour of the young stargazer “being allowed in future to stay at the observatory later than half past ten”. And lo and behold, Kai’s parents quickly relented in response to this impressive petition …
Today, some 23 years later, Prof. Kai Schmitz, is looking out over Lake Aa in Münster, and his eyes light up as he recounts how eagerly he was awaiting the 29th of June, 2023. On that Thursday, as a member of the global “NANOGrav” consortium of physicists, he announced that after 15 years of intensive measurements, convincing evidence had been found for the first time for the existence of slowly oscillating gravitational waves. A scientific coup, a globally acclaimed breakthrough and, at the same time, a moving moment for Kai Schmitz – in the truest sense of the word. “I was very nervous, and all I could think about was that day and our results,” he says. Where does his passion for his subject come from? In order to understand what holds the world together at its inmost folds, as it says in Goethe’s “Faust”? “Children,” he explains, “often ask the question ‘why’ – over and over again – and we physicists take these questions very seriously because, unlike many exasperated parents, we don’t in the end refuse to answer our children’s questions. On the contrary, we want to constantly push the boundaries of our knowledge – and that’s exactly what we’ve managed to do with the discovery of low-frequency gravitational waves.”
Even at a young age, for Kai Schmitz “everything pointed to physics”, although he was also very fond of literature and, by getting the top grade in his Abitur exam, he proved that he had plenty of talent. After six semesters of physics at the FU Berlin, he went travelling: to the USA, Hamburg, Tokyo, Heidelberg, Padua and Geneva. Since May 2022, particle physicist Schmitz – who, in the little free time he has, enjoys exploring the Münsterland region with his family by bike from his home in Gievenbeck – has been teaching and researching at the University of Münster.
Gravitational waves will continue to dominate his work for many years to come. It is known that they care little about obstacles in time and space and rush through everything. But nobody yet knows for sure where they come from. Kai Schmitz and his team are examining the option of whether they are the result of an event which took place around 13.8 billion years ago, when extremely hot plasma drifted apart when the Big Bang – and, with it, the beginning of everything – occurred. The experts are using radio telescopes to observe 68 so-called pulsars – dead stars that rotate rapidly and emit beams at very regular intervals. They function like reliable clocks whose possible timing deviations enable gravitational waves to be measured. “Pulsars, of which we hope to find more, are like lighthouses in space, or light buoys at sea. In any case, they are a gift from the heavens,” says Kai Schmitz.
He prudently keeps expectations in check – although he does seem to have a talent for forecasting. At primary school, he once had to sign an assignment sheet – and he signed it “Prof. Kai”.
Norbert Robers
This article is from the brochure "Twelve months, twelve people", published in February 2024.
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