Universiteit Leiden

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Lecture

This Week’s Discoveries | 24 January 2017

Date
24 January 2017
Time
Explanation
This Week's Discoveries
Address
Oort Building
Niels Bohrweg 2
2333 CA Leiden
Room
De Sitterzaal

Lecture

Title
First light on Verlinde's new theory of gravity

Speaker
Margot Brouwer (Leiden Observatory) is currently doing her PhD in astrophysics at the Leiden Observatory, where she studies the behavior and distribution of dark matter using weak gravitational lensing with the Kilo-Degree Survey. Her research interests include cosmology, dark matter, dark energy, gravity, large scale structure, galaxies, and much more. She also enjoys popular science writing and education.

Abstract
With his new theory of emergent gravity, Verlinde not only claims to explain the mechanism behind gravity, but also the origin of the mysterious "extra gravity" found in galaxies, which is currently attributed to dark matter. We performed a first test of Verlinde's new theory by measuring the curvature of space-time around more than 33,000 galaxies, using a method called "gravitational lensing". For this we employ the 180 square degrees overlap of the Kilo-Degree Survey (KiDS) with the Galaxy And Mass Assembly (GAMA) survey. We compare the observed gravitational lensing effect around galaxies to Verlinde's prediction, which is based only on the normal mass of the galaxies, and find that they are in good agreement without requiring any free parameters.

Second Lecture

Title
Transcription factor DNA binding dynamics in live cells.

Speaker
Veer Keizer (IBL) is a PhD student, funded by FOM, in the animal science & health cluster of IBL. Currently, she is involved in an interdisciplinary research project working together with physics, biology and chemistry to study the use of gold nanorods in live cells. In addition, she studies the dynamics of transcription factors and DNA-binding in the nucleus of live cells.