What phrase did Carl Sagan popularize about the Earth from a spacecraft photo?

The phrase Carl Sagan popularized about Earth from a spacecraft photo was Pale Blue Dot. The phrase refers to a faint, tiny bluish speck visible in an image taken by Voyager 1 on February 14, 1990, when the spacecraft was about 6 billion kilometers from Earth.

Sagan had urged NASA to turn Voyager 1's camera back toward the planets before the spacecraft continued into interstellar space. Earth appeared as a barely visible point of light, caught in a scattered ray of sunlight. The image became one of the most famous photographs in the history of space exploration.

Sagan expanded on the image in his 1994 book Pale Blue Dot: A Vision of the Human Future in Space. He used the photograph to emphasize Earth's small physical scale and the shared fate of everyone who has lived on it. The idea is often confused with “Blue Marble,” which refers to famous full-Earth photographs taken by Apollo astronauts, especially Apollo 17 in 1972.

“Pale Blue Dot” is therefore both a description of the Voyager image and a broader phrase about human perspective and planetary responsibility.