Airs Tuesday, Feb. 4 at 7PM 

UFOs, long a subject of public fascination, are now attracting serious scientific scrutiny. Prompted by widely publicized sightings from Navy pilots, NASA has committed to investigating these unidentified phenomena through a scientific lens.  

Many reports can be traced to mundane sources such as weather balloons, drones, atmospheric phenomena, or optical illusions. However, a subset of sightings remains unexplained, raising compelling questions. Could they represent advanced technology from foreign governments—or even clandestine projects closer to home?  

Another intriguing possibility: extraterrestrial probes. What would it take for alien engineers to traverse vast distances to send probes or visit Earth from other solar systems? NOVA’s investigation looks at the evidence from every angle, astrophysicists and engineers bring new technologies and greater rigor to solving these mysteries.