Science for the Public: Using Gravitational Lensing to Detect Dark Matter , January 14th, 2025. Recorded live at the Beech Street Center, Belmont MA. Guest: Jacqueline McCleary, Ph.D., Assistant Professor of Physics, Northeastern University. Dark matter accounts for some 27 percent of the universe but is invisible. One promising technique to reveal it is the analysis of gravitational lensing that very occasionally aligns galaxy clusters. The much-noted “cosmic question mark” image for this event is the result of a rare alignment between two distant galaxies due to gravitational lensing. Professor Jacqueline McCleary explains how cosmologists use such examples of weak gravitational lensing between galaxy clusters to explore the nature of elusive dark matter and its interaction with galaxies. She discusses how cosmologists gather and analyze data from observatories on mountaintops, in the stratosphere, and in space. 00:42:16