It was Valentine’s Day in 1990. The Voyager 1 space probe, which had completed its primary mission, was leaving the Solar System.
At the request of astronomer Carl Sagan, the American space agency NASA commanded Voyager to turn its camera around and take one last photograph of Earth, across a great expanse of space. The photograph that got clicked was from a distance of about 6 billion kilometers (same as 240,000 round trips from Mumbai to New York).
In the photograph, against the vastness of space and among bands of sunlight scattered by the camera’s optics, Earth appears like a ‘pale blue dot’ (that’s what the photograph was named) that is smaller than a pixel.
Anyways, four years later, in 1994, during a public lecture at Cornell University, Sagan presented the photograph to the audience and shared his reflections on the deeper meaning behind it –