Photograph by NASA, ESA, and J. DePasquale
words by willow defebaugh
Scientists have found evidence of a universal hum, thrumming around and within us—a cosmic sign of our interconnectedness.
“All of a sudden, we know that we are humming in tune with the entire universe, that each of us contains the signature of everything that has ever been.”
Over a century ago, Albert Einstein predicted the existence of gravitational waves—nearly imperceptible ripples in the fabric of space-time that travel unencumbered at the speed of light. It wasn’t until 2015 that scientists actually proved their existence, when observatories in the United States and Italy detected high-frequency waves emitted from the collision of two black holes. For years, scientists have also been looking for signs of ever-present low-frequency waves. Finally, they have found it: the hum of the universe.
In June, hundreds of scientists from all over the world working together under the banner of the International Pulsar Timing Array coalition published their findings about these slow ripples in space-time, described as the background noise of existence. It’s no wonder they were so difficult to detect; they can take decades to cycle up and down. As these subtle waves traverse the universe, they squeeze and stretch everything they come across—including you and me.
In order to uncover signs of this low-frequency rhythm, astronomers looked to the stars. Specifically, they studied pulsars: the dead cores of stars that burned out in supernovas. Some pulsars spin so fast that they flash beams of radio waves at regular intervals—hence why scientists refer to them as cosmic lighthouses. Radio telescopes in North America, Europe, China, India, and Australia measured discrepancies in the timing of the signals from 115 pulsars. These changes in the clockwork of dead stars proved the influence of gravitational waves.
Astronomers have a few theories as to where these gravitational waves come from. One estimates that they emanate from the largest objects in existence: supermassive black holes billions of times more massive than the Sun which could be merging at the center of galaxies. Another theory is that these waves are ripples from the very origin of our universe: the Big Bang. According to the theory of cosmic inflation, the universe exponentially expanded within a second of this unfathomable creation event—and as Edwin Hubble proved in 1929, it’s still expanding.
As astrophysicist Adam Frank wrote for The Atlantic: “every proton and neutron in every atom from the tip of your toes to the top of your head is shifting, shuttling, and vibrating in a collective purr within which the entire history of the universe is implicated. The gravitational-wave background is huge news for the cosmos, yes, but it’s also huge news for you. The nature of reality has not changed—you will not suddenly be able to detect vibrations in your morning coffee that you couldn’t see before. And yet, moments like these can and should change how each of us sees our world.”
A beating heart, a breath of lungs, a baby being born—much like the gravitational waves that hum unseen around us, life is awash with contractions and expansions. Like a pattern repeating at every scale, I have learned time and time again that these two forces go hand-in-hand. And while I never know how long they will last, every state of contraction I have found myself in throughout my life, I have found some form of expansion on the other side. The rhythm is finding a way to trust the beat and dance between these states.
I don’t know whether you are in a state of stretching or squeezing reading this, but I do know that whichever it is won’t last forever. If you feel like a black hole, like gravity is weighing you down, or like your energy has blinked out, reflect on this: even a dead star can be a lighthouse. From their winks and waves, we learned what we have perhaps always known on some indiscernible level, a verity that vibrates at our very cores: we are one with everything.
