Reuters/Alexander Gerst/NASAOn Feb. 14, 1990, famed scientist Carl Sagan gave us an incredible perspective on our home planet that had never been seen before.
As NASA's Voyager 1 spacecraft was about to leave our Solar System in 1989, Sagan, who was a member of the mission's imaging team, pleaded with officials to turn the camera around to take one last look back at Earth before the spaceship left our solar system.
The resulting image, with the Earth as a speck less than 0.12 pixels in size, became known as "the pale blue dot."
Astronauts had already taken plenty of beautiful photos of our planet at that point, and this grainy, low-resolution snapshot was not one of them.
But instead of beauty, this one-of-a-kind picture showed the immeasurable vastness of space, and our undeniably-small place within it.
"Everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives," Sagan later wrote. "On a mote of dust suspended in a sunbeam."
"I was struck by how special Earth was, as I saw it shining in a ray of sunlight," said Candy Hansen, a planetary scientist at the Jet Propulsion Laboratory who worked on the Voyager imaging team. "It also made me think about how vulnerable our tiny planet is."
Voyager 1 had already finished its primary mission of studying Jupiter and Saturn towards the end of 1980, but its mission was extended — and continues to this day — so it could study the far reaches of interstellar space.
First launched in 1977, the robotic spacecraft had already captured incredible images of planets within the Solar System, and eventually, researchers needed to disable its camera so it would have the power it needed to keep transmitting back to NASA once it left.
The striking photograph almost never happened. Early on in Voyager's mission, Sagan had tried to get the look back at Earth, but others on the team worried that the Sun would end up frying the camera. But eventually, with the mission winding down, Sagan finally got his wish — a last minute Valentine's Day gift in 1990.
"You know, I still get chills down my back," NASA researcher Candice Hansen-Koharcheck told NPR. "Because here was our planet, bathed in this ray of light, and it just looked incredibly special."
Voyager 1 took a series of "family portraits" from nearly 4 billion miles away, before its camera was turned off for good. The spacecraft is now the most-distant human-made object in space at roughly 12 billion miles away, and it takes about 17 hours for it to transmit data back to Earth.
NASASagan would later write about the photograph — and the deeper meaning he gleaned from it — in his 1994 book, "Pale Blue Dot: A Vision of the Human Future in Space."
Here's what he wrote:
"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 everyone you love, everyone you know, everyone 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 hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every 'superstar,' every 'supreme leader,' every saint and sinner in the history of our species lived there – on a mote of dust suspended in a sunbeam.
The Earth is a very small stage in a vast cosmic arena. Think of the rivers of blood spilled by all those generals and emperors so that in glory and triumph they could become the momentary masters of a fraction of a dot. Think of the endless cruelties visited by the inhabitants of one corner of this pixel on the scarcely distinguishable inhabitants of some other corner.
How frequent their misunderstandings, how eager they are to kill one another, how fervent their hatreds. Our posturings, our imagined self-importance, the delusion that we have some privileged position in the universe, are challenged by this point of pale light.
NASA/Public domainOur planet is a lonely speck in the great enveloping cosmic dark.
In our obscurity – in all this vastness – there is no hint that help will come from elsewhere to save us from ourselves.
The Earth is the only world known, so far, to harbor life. There is nowhere else, at least in the near future, to which our species could migrate.
Visit, yes. Settle, not yet. Like it or not, for the moment, the Earth is where we make our stand. It has been said that astronomy is a humbling and character-building experience. There is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world.
To me, it underscores our responsibility to deal more kindly with one another and to preserve and cherish the pale blue dot, the only home we've ever known."