Every year on April 22 we celebrate Earth Day. On this occasion we are reminded that we are all cosmic travelers aboard the only home we have, Planet Earth.
On Feb. 14, 1990, NASA's Voyager 1 probe snapped a photo of Earth from 3.7 billion miles (6 billion kilometers) away. The image shows our home planet as it truly is — a tiny, lonely outpost of life in an incomprehensibly vast cosmos — and became iconic as a result.
The Voyager 1 team sensed at the time that the "Pale Blue Dot," as the photo has come to be known, would be an important social document, said planetary scientist Candy Hansen, who served as the experiment representative for the Voyager imaging team and was the first person to set eyes on the Pale Blue Dot photo when it came down to Earth.
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