LISA Pathfinder: Das Herz schlägt

Picked one by one from a mixed channel. Transcript check: both title readers certain; 3 of 5 sampled certain picks confirmed by transcript, none failed. Channel rule: Include only videos that explain gravitational-wave physics, detector or space-mission technology, or present scientific simulations and visualizations. Examples: 'What is GEO600?', 'Detecting Gravitational Waves', 'The path to LISA' technical episodes, the symmetry explainers, and the neutron star merger simulations. Exclude team profiles, interviews, live sessions, promos and mission-milestone or farewell pieces.