On the fourth orbit’s morning pass, the crew watches Saharan dust stream toward the Atlantic and Europe’s mountains slide by. Shaun studies the landmasses and wonders where borders truly sit, feeling the temptation to abandon work just to look, and to know Earth “like another person,” with hungry, possessive yearning.

In the Russian lab, Anton and Roman tend dishes of human heart cells grown from volunteers’ skin samples. Anton is awed by the “absurd miracle” of the living colors under the microscope, while Roman reacts with practical detachment and joking hunger. Their work carries an unsettling parallel: microgravity is also thickening their arteries and weakening their own hearts, even as they preserve heart cells for return to Earth.

As the station crosses the South Pacific in darkness, the chapter widens into reflection on Earth’s deceptive grandeur from orbit and humanity’s slow decentering from old beliefs of cosmic importance. The astronauts’ view triggers thoughts about the search for alien companionship—Voyager’s hopeful messages, decades of listening that return nothing—and a suspicion that loneliness and insignificance may drive humanity’s self-destructive adolescence, until acceptance might bring peace.

News and imagination turn to a new lunar era: four astronauts, recently quarantined in a Cape Canaveral beach hut, launched the previous evening and are now outbound, boosters jettisoned, on a mapped path to the Moon. The six aboard the station mark the moment with balloons and rehydrated desserts, hanging Roman’s felt Moon, but their elation mixes with envy and a quiet backlash at their own “bound-for-nowhere” routine of loyal circling.

Chie copes by pinning up lists of irritations and reassurances in her sleeping quarters, surrounding herself with a few keepsakes. Pietro, thinking about the spectrometer he and Nell installed on their spacewalk, considers what it measures: whether Earth’s radiance is dimming or brightening as pollutants, clouds, and melting ice shift the planet’s energy balance. As he films continents sliding beneath and waits for the typhoon to come into view again, Pietro feels the unrobotic fact of his own heart—fearful, loving, and pounding at what it witnesses.