On their way to the Moon, the astronauts of the Apollo 17 mission placed a Christmas present for the whole human race under the tree.

On their way to the Moon, the astronauts of the Apollo 17 mission placed a Christmas present for the whole human race under the tree.

On Christmas Eve 50 years ago, they captured "The Blue Marble," one of the most moving photographs of the Earth ever.

On Christmas Eve 50 years ago, they captured "The Blue Marble," one of the most moving photographs of the Earth ever.

Photographs taken by Ronald Evans, Eugene Cernan, and Harrison Schmitt with Hasselblad cameras against a backdrop of black oblivion show a vast Africa encircled by the blue Indian and Atlantic oceans.

Photographs taken by Ronald Evans, Eugene Cernan, and Harrison Schmitt with Hasselblad cameras against a backdrop of black oblivion show a vast Africa encircled by the blue Indian and Atlantic oceans.

As CNN wisely notes, the striking image wasn't a viral hit like the most recent JWST images.

As CNN wisely notes, the striking image wasn't a viral hit like the most recent JWST images.

Instead, it developed gradually to become the symbol of the first environmental movement and the Earth Day celebration, which began just two years earlier.

Instead, it developed gradually to become the symbol of the first environmental movement and the Earth Day celebration, which began just two years earlier.

Instead, it developed gradually to become the symbol of the first environmental movement and the Earth Day celebration, which began just two years earlier.

Instead, it developed gradually to become the symbol of the first environmental movement and the Earth Day celebration, which began just two years earlier.