The unofficial Earth Flag associated with Earth Day shows which famous NASA photo?

The unofficial Earth Flag associated with Earth Day shows The Blue Marble, the famous full-Earth photograph taken by the Apollo 17 crew. The image presents Earth as a bright blue sphere against the darkness of space.

The photograph was captured on December 7, 1972, during Apollo 17’s journey to the Moon. Astronauts Eugene Cernan, Ronald Evans, and Harrison Schmitt were traveling roughly 29,000 kilometers from Earth when they photographed the planet, with Africa, Antarctica, and surrounding cloud systems visible.

John McConnell proposed an Earth Flag in 1969, and versions of it were used during the first Earth Day in 1970. The design later incorporated The Blue Marble and became an environmental symbol, although no single Earth flag has official international status.

The image is often confused with Earthrise, photographed by Apollo 8 in 1968, or Pale Blue Dot, taken by Voyager 1 in 1990 from much farther away. The Blue Marble is the Earth-centered photograph linked to this flag.