22 October 2026

Photo: Julie Knudsen

Ever since she was a child, Julie has looked up at the night sky and wondered what lies beyond what we can see. It was not until her first year at university that she found parts of an answer: dark matter. Now she is pursuing a PhD at the Hamburg Observatory and DESY, working to unravel that mystery under the supervision of Prof. Marcus Brüggen and Prof. Kai Schmidt-Hoberg.

Can you tell us a bit about what you did previously and what you are doing currently and why it excites you?

Before starting my PhD, I completed my master's degree in physics at the University of Southern Denmark (SDU), where I performed full physics cosmological simulations with self-interacting dark matter. I am now continuing within the same area in my PhD, where I will also run simulations and work on the phenomenology of self-interacting dark matter. This excites me because dark matter is a fundamental part of our understanding of the universe, yet we know so little about the nature of dark matter.

Why did you choose to pursue a PhD?

I have been interested in physics and astrophysics for as long as I can remember, and pursuing a PhD has been a long-term goal. During my studies, I began working on dark matter in my first year, which confirmed my interest in research. I am motivated by the opportunity to work on an open scientific problem and contribute to understanding it. A PhD allows me to develop my skills as a researcher and work on this question in depth. Although there is a lot to learn at the start, I see this as an important part of the process.

How does it feel like moving to Hamburg?

It has been a change because I moved to another country and started a PhD at the same time, so there have been a lot of new things to take in. But it has also been really exciting, and Hamburg already feels like a city with a lot to explore. I am looking forward to getting more settled, meeting more people, and discovering more of the city.
 

What advice would you give someone who is thinking about pursuing a PhD?

My advice would be to find a research topic that genuinely interests you, as you will spend a lot of time thinking about it. I think it is especially important to choose something that you are genuinely curious about and want to understand more.