The Big Bang theory holds that the universe began around twelve billion years ago as a compressed, seething mass of energy that suddenly expanded outward, and this four-episode series tracks the cosmologists trying to confirm the details of that story. John Hurt narrates, and the visuals lean heavily on Hubble Space Telescope photography mixed with computer-generated recreations of supernovas, black holes, and galaxy formation. Working scientists appear throughout to explain their current research, including the ongoing hunt for dark matter and dark energy, the invisible components thought to make up most of the universe's mass and energy but detected so far only through their gravitational effects rather than direct observation. The series moves from the earliest fractions of a second after the Big Bang through the formation of stars and galaxies, treating each stage as an open research question rather than settled history. The pairing of real telescope imagery with modeled animation is the show's main device for making processes too vast or too old to film feel visible on screen.