"Space Explorers: Blue Marble - Orbit 1" "Filmed outside the ... around the Earth at a speed of 17,500 miles per hour on a crystal-clear day." "Join NASA astronaut Megan MacArthur as she opens ...

The "Blue Marble" was the first photograph of the whole Earth and the only one ever taken by a human. Fifty years on, new images of the planet reveal visible changes to the Earth's surface.

The iconic photo, known as “Blue Marble,” was taken by NASA astronauts Eugene “Gene” Cernan, Ronald Evans and Harrison Schmitt on December 7 using a Hasselblad camera and a Zeiss lens ...

Here’s how it works. Why it's incredible: The marble walls reflect the turquoise color of the water in the cave, tinting them blue. The Marble Caves are natural rock formations with curved walls ...