On July 19, 2013, the Cassini spacecraft took a series of pictures of Saturn as it was backlit by the Sun. In those images, appearing as little more than a tiny dot 1.4 billion kilometers away, was the Earth.
NASA’s Jet Propulsion Laboratory organized an event called “Wave at Saturn”, encouraging people to go outside and wave at the ringed planet while the images were taken. They also encouraged people to take pictures of themselves waving, and to submit them to JPL.
People did so, in droves, from 40 countries around our planet. The folks at JPL collected the photos and did something astonishing and lovely: Using an image of Earth as the index, they created the fantastic montage (shown above) of our planet, making what is essence a map of Earth as it was seen from Saturn at the time! It's a depiction of Earth using pictures from Earth as Cassini looked back at Earth.
In this picture you can see that all of South America as well as parts of North America and Africa were facing Saturn at the time. And if you grab the huge full-res version, you can see the thousands of individual pictures people submitted that comprise the montage.
I love this idea, and love the result. Looking at the big picture (literally and figuratively) I see a lot of younger people in these pictures, enthusiastically participating. That makes me hopeful. Saturn is a planet: a thing, an unthinking ball of gas, ice, metal, and rock. It doesn’t care if we wave to it or not. But this wasn’t done for Saturn, it was done for us. We are the ones who care, we are the ones who seek out knowledge, we are the ones who explore the Universe just to satisfy our curiosity, to find our place in it, to find the beauty in it, to increase our understanding of it.
If that exploration has more tangible results—and it always does—that’s icing. But we shouldn’t forget that we do this because it’s part of being human. And to me, that’s the greatest reason there is.