Oliver Müller – Dwarf galaxies are quite orderly after all

He challenged the standard model of cosmology in his dissertation by demonstrating that dwarf galaxies have not invariably chaotic motions, but can also orbit around the main axis of their parent galaxy in an orderly fashion. This got Oliver Müller the Prix Schläfli award in Astronomy.

Oliver Müller, Prix Schläfli 2020
Image: Eva Schnider

One can well imagine him as a person filled with awe and wonder for all eternity. An artistic personality with long hair, gazing at the night sky with fascination, absorbed in the sight of the universe. In fact, Oliver Müller experienced a kind of “Eureka!” moment, one that led him into astronomy, when he visited the Metzerlen-Mariastein observatory. "As a city kid I didn't know the night sky. I was fascinated."

He became increasingly interested in the world of stars, especially dwarf galaxies. Dwarf galaxies are particularly important for science as they allow indirect observation of dark matter. Dark matter accounts for about 80 percent of all matter in the universe and is regarded as the driving force behind the formation of structures, including galaxies and their vicinities. The standard cosmological model assumes that dwarf galaxies move around their parent galaxie in a random and chaotic manner. However, researchers have observed for some time that the dwarf galaxies around the Milky Way do not conform to this assumption. "For a long time, this was considered an anomaly of our galactic system," explains Müller. The thought that there might be more “anomalies" out there did not let go of him. And true enough, 14 out of 16 known dwarf galaxies in our neighbouring group of galaxies, Centaurus A, showed the same, symmetric movement pattern.

Nevertheless, this was only half the breakthrough. Müller put a research team together at the University of Basel to determine the statistical significance of these movement patterns. The results made it to the front page of "Science" and created a huge sensation both among experts and the public. "At the moment, our findings are still academic," says Müller, “but 200 years ago, the discovery of electricity was also academic." His findings could ultimately lead to reconsider the standard cosmological model.

Whoever spearheads such a revolution is certainly worthy of the Prix Schläfli award. However: "Frankly, I cannot believe it. It is completely surreal," he says. This may be due to the fact that the 30-year-old had, until now, not shown much academic flair. He points out, "the award shows me that you don't have to be a genius to succeed. Rather, will and joy count as well”. He was the first in the family to pursue an academic career.

Müller is currently researching at the observatory of the University of Strasbourg with a scholarship from the Swiss National Science Foundation. Normally, he also visits his girlfriend in Basel once a week, where he also teaches Japanese sword fighting. On his last trip he got involuntarily stuck at the Rhine knee: it was the day before the lockdown, and he was not able to return to France as planned. Fortunately, he could pursue some of his hobbies during the mandatory lockdown, such as playing electric guitar and writing. Much of the latter is for his blog at Spektrum der Wissenschaft "Prosa der Astronomie”, where he gives a wider audience an understanding of his scientific findings: a stargazer who also opens up the vistas of the universe to others.

Astrid Tomczak-Plewka

One of the dwarf galaxies which is orbiting around our Milky Way galaxy as part of a planar structure.
One of the dwarf galaxies which is orbiting around our Milky Way galaxy as part of a planar structure.Image: ESO/Digitized Sky Survey 2