More than 100 years ago, Albert Einstein explained gravity to us with his general theory of relativity. The theory of relativity is still used today, for example for the GPS satellite navigation system. Einstein's theory predicted incredible objects: black holes whose gravity is so strong that not even light can escape them. Something that has fallen into a black hole will never get out again. Observations with telescopes later confirmed that black holes are a reality.

But how do you study black holes? After all, they are very far away from us and difficult to observe. Stars orbiting a black hole, on the other hand, are easy to observe. The properties of the black hole, such as its mass, can be calculated from the orbits of the stars. From the point of view of theoretical physicists, orbital curves, known as geodesics, are therefore of particular interest. For models of black holes in many physical theories, orbital curves of objects orbiting around the black holes can be calculated. This allows us to find out a lot about the nature of black holes.

Gravity still presents us with many unsolved mysteries. Einstein's theory of relativity does not really fit with quantum mechanics. This is why alternative theories of gravity are also being researched; many of these theories even assume a higher-dimensional world. Most alternative theories are complicated, meaning that only numerical models can be created. Research into black holes in these theories helps us to better understand gravity.

Latest developments:

The shadow of a supermassive black hole in the galaxy M87 was published in 2019(ApJL 875 L1). This observation is considered confirmation of Einstein's theory of relativity.

The direct detection of gravitational waves(PRL 116, 061102) in 2016 by LIGO/Virgo was honoured with the Nobel Prize. The gravitational waves were emitted when two black holes merged.

If you are interested in writing a thesis in this or a similar field, please contact or .