Today marks the fortieth year of the famous “blue marble” photograph of Earth taken by the crew of Apollo 17.

Earth seen from space on December 7, 1972.

Earth seen from space on December 7, 1972.

This iconic photograph has inspired millions of people over the years. By seeing the Earth hanging in space, we suddenly became aware if just how fragile our existence is. While environmental concerns were not new in the ’70’s, this picture put them under a magnifying glass, as have numerous images of our planet taken since this iconic photo was first released.

It is interesting to see that programs designed to look beyond our planet can sometimes give us an even better view of our own challenges and opportunities. Apollo 17, after all, was headed to the Moon. It was great they thought to look back.

Happy birthday, Blue Marble – and may we have many, many, more.