What happens when Earth gets no second chance? This video explores how to stop an asteroid, highlighting NASA's successful double asteroid redirect test (DART) mission. We examine the critical role of planetary science in understanding and mitigating cosmic threats, alongside strategies like multiple kinetic impactors and nuclear devices for scenarios like 2024 PDC-25. The DART mission, which successfully altered dimorphos orbit, validates kinetic impactors as primary asteroid deflection tools,