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.