Earth's history is marked by one cosmic disaster after another, forging the path of human evolution. Asteroid and comet collisions, flares from the Sun, mass extinctions, supernova explosions, cosmic ray bombardment. You name it, we've experienced it. It's kind of a miracle we're here at all. Now, experts explore how the Earth has teetered on the verge of destruction.

The Rosetta mission was a ground-breaking expedition to land on a comet for the first time, the 67P/Churyumov-Gerasimenko comet. The Rosetta mission tries to answer our most fundamental questions and to change our understanding of the cosmos forever. Special access reveals what this cutting-edge journey discovered and how these mysterious objects helped create life on Earth.

The message of the group begins to change and losing identity and group mentality is pushed. With more lockdowns and rules, longtime members of the group begin to question or leave. With no sex permitted with members, Dick Joslyn’s membership in the cult poses problem for Do... leading to a new request for the group.
With dwindling numbers, the group needs a new boost of membership. The Exit begins to be discussed as the Hale-Bopp Comet approaches.

The Hale-Bopp Comet is passing Earth and rumours of a mysterious object following the comet could mean the sign that the Heaven’s Gate community could be looking for. With plans for the Exit, the group members begin saying goodbye to the world. In the aftermath of the suicides, the world and the surviving former followers react.

When a mysterious cigar-shaped object is spotted tumbling through our solar system, experts race to uncover it's true nature. The object, nicknamed Oumuamua, meaning 'a messenger that reaches out from the distant past' in Hawaiian, was discovered by the Pan-STARRS 1 telescope in Hawaii. Since its discovery, scientists have been at odds to explain its unusual features and precise origins, with researchers first calling it a comet and then an asteroid before finally deeming it the first of its kind: a new class of 'interstellar objects.'
A recent paper by researchers at the Harvard Smithsonian Center for Astrophysics raises the possibility that the elongated dark-red object, which is 10 times as long as it is wide and travelling at speeds of 196,000 mph, might have an 'artificial origin.' The theory is based on the object's 'excess acceleration,' or its unexpected boost in speed as it travelled through and ultimately out of our solar system.

The episode begins with Tyson describing how pattern recognition manifested in early civilization as using astronomy and astrology to predict the passing of the seasons, including how the passage of a comet was often taken as an omen. Tyson continues to explain that the origin of comets only became known in the 20th century due to the work of Jan Oort and his hypothesis of the Oort cloud. Tyson then continues to relate the collaboration between Edmond Halley and Isaac Newton in the last part of the 17th century in Cambridge. The collaboration would result in the publication of Philosophiæ Naturalis Principia Mathematica, the first major work to describe the laws of physics in mathematical terms, despite objections and claims of plagiarism from Robert Hooke and financial difficulties of the Royal Society of London. Tyson explains how this work challenged the prevailing notion that God had planned out the heavens, but would end up influencing many factors of modern life, including space flight. Tyson further describes Halley's contributions including determining Earth's distance to the sun, the motion of stars and predicting the orbit of then-unnamed Halley's Comet using Newton's laws. Tyson contrasts these scientific approaches to understanding the galaxy compared to what earlier civilizations had done, and considers this advancement as mankind's first steps into exploring the universe. The episode ends with an animation of the Milky Way and Andromeda galaxies' merging based on the principles of Newton's laws.