"[3][4] Despite favorable reviews, however, the episode received a 1.5/4 in the 18-49 rating/share demo, with 3.91 million Americans watching it live on Fox, showing a steady decline from the series premiere.
Tyson further explains how modern astronomy has used such analysis via deep time to identify the Big Bang event and the age of the universe.
Tyson proceeds to describe how the work of Isaac Newton, William Herschel, Michael Faraday, and James Clerk Maxwell contributed to understanding the nature of electromagnetic waves and gravitational force, and how this work led towards Albert Einstein's Theory of Relativity, that the speed of light is a fundamental constant of the universe and gravity can be seen as distortion of the fabric of space-time.
Tyson then describes the nature of black holes, their enormous gravitational forces that can even capture light, and their discovery via X-ray sources such as Cygnus X-1.
Tyson ends on noting that Herschel's son, John would be inspired by his father to continue to document the known stars as well as contributions towards photography that play on the same nature of deep time used by astronomers.