My colleague and friend Darko Žubrinić, professor of Mathematics at the University of Zagreb (employed at the Faculty of Electrical Engineering and Computing) inspired me to connect natural phenomena with human nature. Namely, he likes to connect seemingly unrelated things.
Once I had the opportunity see the whole circle rainbow, that is, not just the usual semicircular one. For this to be possible, one has to be at a sufficiently high altitude, say, in the mountains. This extremely rare picture is one of the most amazing sceneries that I have ever witnessed. The secondary rainbow was also very clearly visible, as well as the projected cross in the middle, with two waving human silhouettes left and right of it. My colleague and me, we have climbed to the top of the mountain, standing left and right of the metal cross, which was about 4 m of height. Since then, this has become my favorite mental picture, which I revive very often in my mind. It brings me in the mood of peacefulness and consolation. As for the secondary rainbow, it is interesting that in his well known monograph The Optics published in 1704, Sir Isaac Newton attributes its physical explanation to distinguished Croatian spiritual writer Mark Antun de Dominis (1560-1624). Mark Antun was born as Marko Domnianich on the island of Rab, just under the legendary mountain of Velebit, which offers spectacular view to dozens of Croatian islands. Mark Antun de Dominis was especially esteemed in England, where he was invited by king James I. There he lived at the Court of the Archbishop of Canterbury and was appointed to be the Windsor Dean and the king's chancellor.
Some of the greatest human minds were studing these phenomena in great detail, and the knowledge gathered is lectured at high schools and universities worldwide. One of the most important contributions to our present understanding of the nature of seismic waves was made by Andrija Mohorovicic (1857-1936), professor of geophysics at the University of Zagreb. Thanks to collected dana about earthquaqes in Croatia in 1909, using a very clever and simple physical argument, he discovered a major discontinuity at a depth of about 55 kilometers below the surface of the Earth. This discontinuity, now universaly known as the MOHO discontinuity, defines the crust of the earth. Here, we can add the name of his son, Stjepan Mohorovicic (1880-1980), professor of physics at a grammar school in Zagreb, who made a very interesting theoretical discovery of the positronium (a rotational pair of electron and positron) as early as in 1934, published in Astronomishe Nachrichten in Vienna. Its existence was confirmed experimentally in 1951 by Martin Deutsch, MIT physicist and a member of Manhattan Project. Still earlier, in 1927, Stjepan Mohorovicic predicted the existence of the MOHO discontinuity on the Moon, analogous to that of the Earth, discovered by his father Andrija. Its existence has been finally proved in 1969 during the famous Apollo 11 flight to the Moon. Seismic measurements have been carried out by Neil Armstrong and Edwin Aldrin, the first humans to land on the Moon.
In January 2016, Slobodan Lang (1945-2016), professor of social medicine at the University of Zagreb and a visiting professor at Harvard University, died in his native city of Zagreb. He was distinguished humanitarian activist, certainly one of the greatest of the 20th century. Among his numerous achievements, we mention the operations "Convoy for Dubrovnik" in 1991, the "White Road for Nova Bila and Silver Bosnia" in 1993 (which was the first joint Muslim - Christian humanitarian operation in history), as well as the operation "Save Life" in 1995. We believe that the practical experience gathered by means of his theory of the "Challenge of Goodness" provides a basis for solving various conflicts throughout the world. In 1999, he wrote the following: "In the next ten years we can expect approximately 30 new wars in which millions will be killed, twice as many will be wounded and many times more will be displaced or exiled. Each of these conflicts will primarily be directed against civilian populations. As we approach the new millennium, we must be aware that the maintenance of peace, the prevention of war, the protection during wars and postwar reconstruction are first and foremost public health and human rights issues." Professor Lang has Croatian and Jewish ancestry and is highly esteemed in Croatia and B&H.