Hi! Welcome to the first pub lecture of the year! It is an incredibly fun activity and you really don't want to miss it! During a pub lecture, we rent a pub in Utrecht in the evening, and then 2 physics/mathematics teachers give a short lecture on a topic that has something to do with physics/mathematics. Between the chats there is plenty of room to have a nice chat while enjoying a drink. This time you can enjoy the next 2 speakers in Josefien bar. Barbara van den Berg will tell us more about the mathematics behind DNA analyzes used in court, and Tanja Hinderer will talk about discovering black holes with gravitational waves.

Tanja Hinderer: Einstein’s theory of gravity as curved spacetime has two profound consequences (also recent Nobel Prizes): black holes and gravitational waves. Black holes are made of warped spacetime and intangible, with an event horizon demarcating their interiors. Gravitational waves, ripples in spacetime that are copiously produced, for example, by collisions of two black holes, are unique fingerprints of their sources and a clean channel of information on dark sectors of the universe. First observed in 2015, gravitational waves have since then revealed a first census of black holes in the cosmos within the reach of current detectors, which already contains surprises. Moreover, they have started to enable us to probe deeper questions about the fundamental structure of black holes and related to theoretical puzzles such as the information paradox. In this talk, I will introduce gravitational waves as probes of black holes and some of the challenges in this endeavor, discuss examples of what we have learned from recent measurements, and end with an outlook to the exciting prospects in the coming years..

Barbara van den Berg: Imagine: you are a judge in a criminal case against a robbery suspect. There are camera images of the robbery showing the face of the perpetrator. The images were compared with photos of the suspect's face by a forensic expert. The expert finds many similarities in facial features between the images and the photos and states that the combination of these features is rare. The expert therefore reports to the court that after extensive research it appears that "the findings of the facial comparison based on the given visual material are much more likely when the person depicted is the same person than when it concerns a different person." Well... what can you as a judge conclude about the chance that the suspect is the perpetrator?