Of all the space photos NASA has ever made, there are a few that are as iconic as an image Voyager took looking back at Earth from Saturn. It's a picture known among space nerds as the 'Pale Blue Dot.'
Its notoriety is largely due to Carl Sagan, who put the image on his show, Cosmos, and rapturously contrasted the smallness of Earth in space with the profusion of everythingness that the human perspective sees on this planet.
From this distant vantage point, the Earth might not seem of any particular interest. But for us, it's different. Consider again that dot. That's here. That's home. That's us. On it, every one you love. Every one you know. Every one you ever heard of. Every human being who ever was lived out their lives. The aggregate of our joy and suffering. Thousands of confident religions, ideologies, and economic doctrines.... Every saint and sinner in the history of our species lived there, on the mote of dust, suspended in a sunbeam.
If gorgeous blue-and-green whole-Earth photos emphasize the uniqueness of humans' home, the pale blue dot provides "an alien view of Earth." You are here, it says, and that is nowhere in astronomical terms.
For most, or for me, at least, that could inspire existential dread. But the glory of Sagan is that it never did. Wonder, rapture: Those were his modes.
Carolyn Porco, who heads the imaging team for the Saturn-orbiting Cassini experiment, is an astronomer in the Sagan mold. She is a poet of space, prone to fits of awe and expansiveness on her blog, which she calls, "Captain's Log."
So it is appropriate that Porco would lead a team that would reprise the Pale Blue Dot, imaging the Earth while Saturn (from Cassini's perspective) eclipsed the sun. They'd already done it once before in 2006, and that second Pale Blue Dot became Cassini's "most beloved image." This time, they added a little earthly razzledazzle, though. The astronomers asked people on Earth to look up into the sky for the moment of imaging on July 19, 2013.
"The plans for the July 19 mosaic included something very special," Porco wrote. "If all went well, the images would capture a glimpse of Earth alongside Saturn and its rings at the very moment that people all over the globe would be contemplating their connectedness to each other and to all life on Earth, appreciating the rarity of our planet within the solar system, marveling at their own existence, and rejoicing at the very thought of having their picture taken from across the solar system."
Today, NASA released the composite image from July 19, and we have a new Pale Blue Dot to contemplate.
Porco calls the image, "The Day the Earth Smiled."
Now, look one more time. There, below the main rings and to the right of the globe of Saturn, far in the distance and seemingly lost in the radiance of the scene, lies a small speck of blue light, floating in a sea of stars. That is our home, with every last one of us on it ... you, me, the folks down the block, even those on the opposite side of the Earth ... we all inhabit that lovely blue dot.
And more than this ... the image of that dot captures the very moment, frozen in time, when the inhabitants of our planet took a break from their normal activities to go outside and acknowledge our 'coming of age' as planetary explorers and the audacious interplanetary salute between robot and maker that this image represents.
I hope long into the future, when people look again at this image, they will recall the moment when, as crazy as it might have seemed, they were there, they were aware, and they smiled.
In other words, Carolyn Porco: a Sagan for our time.