We are used to consider the periodic planetary movements in our solar system as well-determined and eternal. Our categorisation of time is based on the movement of the earth around itself and around the sun. But what happens on a larger scale when we include other stars or even galaxies in our considerations and look at their overall interaction?

Rainer Spurzem's research group in Heidelberg simulates the movement of millions of stars in clusters and analyses the effect of gravity between all objects. Clusters that are close enough to each other to be able to influence each other gravitationally are of particular interest. In such systems, deterministic chaos arises due to irregular orbits; objects (e.g. black holes) can merge by emitting gravitational waves and then move along new orbits in the system.

Rainer Spurzem from Heidelberg will be a guest scientist at FIAS in 2025. In a lively and exciting small workshop in January, he and his working group introduced themselves at FIAS. The presentation showed that collisions of galaxies, stars and black holes can also occur on different scales within our Milky Way.

Spurzem, active at Peking University and the National Observatory of the Chinese Academy of Sciences ((Beijing, China) as well as the Astronomical Computing Institute in Heidelberg, investigates the dynamics of star clusters and black holes with the help of supercomputers. Presentations by his team described globular cluster simulations, planetary systems and massless particles in star clusters, interacting dark matter and how black holes can be ‘weighed’.

Peter Berczik, a long-time member of the team, develops orbital parameters of the Milky Way's globular clusters and describes the interaction with the galactic centre. This topic fits perfectly into the scientific portfolio at FIAS, where corresponding simulations are possible on the high-performance computers in Volker Lindenstruth's working group.