On April 10, 2019, the world was mesmerized by the spectacular first-ever photo of a black hole, providing the first visual evidence that black holes actually exist. The black hole is located at the center of the galaxy named Messier 87 (M87), about 55 million light-years from Earth. The black hole has a mass equal to 6.5 billion times that of the sun. The photo was the result of a ten-year collaboration of more than 200 researchers using a global network of eight radio telescopes, known as the Event Horizon Telescope Collaboration (EHT), to combine all their observations and data (5,000 trillion bytes over two weeks) in a supercomputer to create the virtual image. Shepard Doeleman, director of the EHT, proudly proclaimed: “We have seen what we thought was unseeable.” This is truly a remarkable, monumental photo. But there is another one…
Six years ago, Avery Broderick, a theoretical astrophysicist and a fellow member of the EHT, noted that the first picture of a black hole could be just as important as a photo known as the “Pale Blue Dot.” That photo, taken almost 30 years ago has slipped from the collective memory of the public. But it shouldn’t — because it is a truly remarkable technical and astronomical achievement. Let’s take a trip back into time, going back 42 years ago…
The Voyager 1 spacecraft was launched by NASA on September 5, 1977 aboard a Titan IIIE rocket. The space probe was designed to study the outer solar system, flying by Jupiter, Saturn, and then flying through the heliosphere, and eventually into interstellar space. At a speed of about 38,027 mph, the intrepid Voyager 1 covers a distance of about 325 million miles per year. And remarkably — 37 years later — the spacecraft is still sending data to NASA (messages from more than 12 trillion miles away take about 17 hours to reach Earth). Back in 1990, astronomer Carl Sagan, who was a member of the Voyager’s imaging team, persuaded NASA to send commands to turn the spacecraft’s camera around to take one last photo of the Earth (at a distance of about 3.7 billion miles away). The final image shows the Earth as a mere speck (less than 1 pixel) suspended in a brownish band of light, surrounded by the blackness of space.
The spectacular photo inspired Sagan to reflect so eloquently, so beautifully on the significance of life on this tiny planet, a pale blue dot, dwarfed by the mind-boggling vastness of the cosmos: “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. Our 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.”
These two photos — the first-ever black hole of M87 and the Pale Blue Dot — could not be more different, occurring at such amazingly different chapters in the history of the world, but they are a singular and profound reminder of just how insignificant our existence is in the context of an infinite, ever-expanding cosmos. And from time to time, we need spectacular photos like this to remind us to be more humble.
For further reading: Pale Blue Dot: A Vision of the Human Future in Space by Carl Sagan, Ballantine Books (1997)
Cosmos by Carl Sagan, Ann Druyan, and Neil deGrasse Tyson, Ballantine Books (2013)
Universe by Robert Dinwiddle, Philip Eales, David Hughes, and Iain Nicolson, DK (2012)