Scienti
Fika
is the place to be every Friday afternoon if you want to learn more about a variety of research fields while enjoying delicious Fika! We bring together researchers across different universities in Stockholm to share their passion for science and related topics, while nourishing a deep sense of community among junior researchers.
Upcoming
Friday 16:00 @ Nordita 6th floor
2025-10-10
✨ Open to juniors* ✨
Azi Fattahi
Gravitational lensing is the bending and distortion of light by massive objects like stars and galaxies. In rare cases—strong lensing—it produces multiple images of the same background source. Thanks to wide-field sky surveys and modern discovery methods, more than 1,000 strong lenses are now known. In this talk I’ll present a history of gravitational lensing: early predictions, how Einstein got lucky, how Einstein was wrong, accidental discoveries, and modern telescope efforts. I will focus on one powerful application—time-delay cosmography—showing how differences in arrival times between images allow us to measure the Universe’s expansion rate, addressing the Hubble tension, today’s biggest debate in cosmology.
*Junior audience is a term that encompasses undergraduate, master's, and PhD students, as well as postdocs.