Pale Blue Dot: A Vision of the Human Future in Space

The next few chapters focus on current events of the early 1990s in relation to the future of space exploration. Sagan returns to the theme of cosmic perspective—looking at Earth from space—and includes the view of Earth from the Moon (174). He reiterates that whole-Earth images make it clear that Earth’s environment is more than a nationalist concern. Humans are at a fork in the road where things like ozone layer depletion, greenhouse warming, and nuclear winter threaten the future of the species, and Sagan argues that space programs provide the kind of transnational vision needed for humans to recognize how urgent the situation is. Contemplating Earth from orbit tends to diminish feelings of nationalism (175).

Sagan argues that comparative planetology is invaluable when it comes to learning more about Earth, including possible solutions for Earth’s climate crisis. By studying other planets, we have already learned more about volcanos, earthquakes, and weather. We might one day learn how life emerged on Earth by studying the same circumstances elsewhere. By studying other planets, we can get a more complete sense of what can go wrong: “Other worlds provide vital insights about what dumb things not to do on Earth” (175).

The rest of the chapter focuses separately on three crises.