LIGO Reactivated with Enhanced Sensitivity for Uncovering Universe's Secrets.

The upgraded Laser Interferometric Gravitational-Wave Observatory (LIGO) has been reactivated after a three-year break, with improved sensitivity to measure gravitational waves. LIGO's fourth observation run will focus on real-time detection and localization of gravitational waves, which offer new opportunities for multi-messenger astronomy and deepen our understanding of astrophysical phenomena. Upgrades to the mechanical equipment and data processing algorithms should allow LIGO to detect fainter gravitational waves than in the past. The observatories have still not yet achieved their maximum design sensitivity.