Sixteen Sunrises, a Thin Blue Line: The ISS View of Earth's Atmosphere

Astronauts aboard the ISS experience about 16 sunrises and 16 sunsets each day as the station orbits Earth roughly every 90 minutes; from orbit the atmosphere appears as a narrow blue limb rather than a hard boundary, underscoring the air’s fragility and the perspective-shifting overview effect that comes from viewing our planet from space.