The cosmic journey from the Big Bang to stardust

“We live in the golden age of astronomy,” were the words of Professor Andreas Burkert of the Ludwig Maximilian University of Munich, who gave a captivating lecture on the Big Bang and the universe in the Benedikt-Statler-Gymnasium’s final auditorium on Thursday.

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Technological advances in the past few decades, from powerful telescopes and satellites to supercomputers, have enabled people to constantly discover new things in the universe. With his stated goal of conveying “the beauty of understanding,” he led the large audience on a fascinating journey, from the smallest atom to the clusters of galaxies and cosmic filaments, the largest structures in existence in the universe.

Galaxy explained

The starting point of the journey was our solar system. Burkert explained that the solar system, like all the stars in the galaxy, revolves around the center of the Milky Way and travels about ten million kilometers in eight hours. The Sun and large gaseous planets such as Jupiter and Saturn are composed mostly of hydrogen and helium, while the inner planets are composed mostly of heavier elements such as carbon, nitrogen, and oxygen. But where do these elements come from? The lightest molecules, hydrogen and helium, were created shortly after the Big Bang, “the day before yesterday,” 13.82 billion years ago.

However, larger atoms, from lithium to iron, did not originate in the Big Bang, but in stars through nuclear fusion processes. In this sense, the Earth and all life on it, especially us humans, are made of “stardust.” Atoms heavier than iron only arise in supernovas, the massive explosions in which giant stars largely end their existence. These giant stars burn up mass so quickly in their basic processes that they last “only” a few tens of millions of years. On the other hand, red dwarfs, which are stars much smaller than our Sun, cannot be seen from Earth with the naked eye. To do this, they burn up their nuclear material so slowly, over a period of up to a trillion years, that not a single red dwarf has emerged since the beginning of the universe.

The lecture did not only address the end of stars, but above all their formation, which is what Burkert and his colleagues are researching. Using scientific simulations, Burkert showed how stars form in massive interstellar gas clouds. He provided actual recordings of such gaseous clouds as the famous “Pillars of Creation,” thereby admirably confirming his initial thesis on the “beauty of understanding.”

Extraterrestrial life?

Professor Burkert also commented on the issue of extraterrestrial life in the universe. There are about 100 billion galaxies in the observable universe, and each galaxy contains on average 100 billion stars. “There are so many that even a grain of sand placed at arm’s length on your finger obscures the 6,000 galaxies beyond it in the field of view,” explained Burkert, who always provides vivid examples of almost unimaginable size dimensions, from atom to atomic dimensions. Cosmic structures have been found. Science now strongly believes that almost every star has one or more planets, so there are likely more planets in the universe than stars. “With this number of planets, it is difficult to imagine that we should be the only ones with life in the universe,” Professor Burkert summarized.