Course | Black holes: current knowledge

1. Wednesday 11 March: What are black holes? 

   Black holes are an extreme form of gravity: their gravitational pull is so strong that even light cannot escape! A logical question is therefore: how do we actually know that they exist? We will discover this together in this first lecture. We will also discuss the history of black holes, what it feels like to jump into a black hole, and all kinds of black holes – from small black holes about a kilometre in size to supermassive black holes that are billions of kilometres in size. 
   Béatrice Bonga
    

2. Wednesday 18 March: Seeing black holes

   The interior of black holes is shielded from observation by an “event horizon”, a virtual one-way membrane that matter, light and information can pass through, but from which they can never return. In recent years, using the global network of radio telescopes, the “Event Horizon Telescope”, we have captured the first images of supermassive black holes and detected their dark shadows. Detailed supercomputer simulations accurately replicate these observations. Can we now literally look into the abyss of a supermassive black hole's event horizon?
   Heino Falcke
    

3. Wednesday 25 March: Hearing black holes 

   Since 2015, we have been able to detect gravitational waves. This has opened up a whole new way of measuring black holes, a way that is more like hearing than seeing. Hundreds of colliding binary black holes have already been found, yielding a wealth of new information, but also raising many new questions. Current and new instruments, such as the Einstein Telescope and the LISA mission, will yield much more information.
   Gijs Nelemans
    

4. Wednesday 1 April: Finding black holes

   A black hole has mass. And we are now able to determine this mass. It tells us something about how a black hole is formed, and thus also something about its origin. Stars can be torn apart by black holes. What can we learn from these fascinating events? And did you know that you can discover new black holes using the “Black Hole Finder App” and thus give science a helping hand? You will hear more about this in this lecture. 
   Peter Jonker
    

5. Wednesday 8 April: Black holes, do they really exist? 

   Marij van Strien addresses the more philosophical questions related to black holes, such as: why has the universe fascinated us since time immemorial; and how do you know if something exists if you cannot observe it? And can you really speak of observation when modelling, calculations and instruments lead to conclusions rather than observations with the naked eye? The last half hour of this lecture will be a review of the series, led by Béatrice Bonga.
   Marij van Strien en Béatrice Bonga 

Béatrice Bonga is a university lecturer in High Energy Physics and conducts research in theoretical physics. She focuses in particular on fundamental questions in general relativity theory and on predictions for future gravitational wave detectors, such as the Einstein Telescope and LISA.

Heino Falcke is Professor of Astroparticle Physics and Radio Astronomy at the Institute for Mathematics, Astronomy and Particle Physics (IMAPP) at Radboud University. His research includes the role of supermassive black holes and jets in galaxies, using theoretical, observational and experimental astronomy.

Gijs Nelemans is Professor of Gravitational Wave Astrophysics at Radboud University and conducts research into the evolution of binary stars, in particular the formation of binary stars from white dwarfs, neutron stars and black holes, and sources of gravitational waves.

Peter Jonker is Professor of Observational High Energy Astrophysics at Radboud University. His research focuses on determining the masses of black holes in order to gain more insight into the formation of black holes.

Marij van Strien is a university lecturer in History of Philosophy at Radboud University. Her research focuses on the history and philosophy of the natural sciences, in particular physics.