For decades some have suspected that there might be others out there, intelligent beings capable of communicating with us, even visiting our world. It might sound like science fiction, but today scientists from across the globe are scouring the universe for signals from extraterrestrials. Horizon obtained exclusive access to film researchers at the Green Bank Telescope searching for radio signals from Tabby's Star, a star so mysterious that some scientists believe it might be surrounded by a Dyson Sphere, a vast energy collector built by advanced aliens.

Deep in the mountains of West Virginia, the Green Bank Observatory has been receiving a mysterious signal from deep space. A team of astronomers has been detecting high-energy bursts erupting from unknown sources far off in space since years ago. But one of them is different from the rest. They call it FRB 121102.
What is actually giving rise to this very powerful flash? Could this be a message from an advanced civilization, or is it a much stranger and violent occurrence? Visit the largest steerable radio telescope on the planet for answers.