Amundsen-Scott South Pole Station experiences months of darkness. The sun dips below the horizon on March 21, after which follows several weeks of twilight before complete darkness results. Photo taken on June 25, 2009. (National Science Foundation/Jeremy Johnson)

A woman holds up the Chinese national flag as people gather to watch the the launch of the Long March 5B rocket carrying China's Tianhe space station core module from the Wenchang Spacecraft Launch Site in Hainan Province, China, 29 April 2021. China launched into space the core module of its space station, marking the beginning of a series of launch missions to complete the space station by the end of next year. (Photo by Matjaz Tancic/EPA/EFE)