PRACTICALLY NEGLIGIBLE

Imagine having to measure a change in distance so tiny that even if you divided the thickness of a hair by a million, you would still be off the mark: we are talking about one billionth of a billionth of a meter. Yet this is the magnitude of the deformation that our instruments had to detect in order to say: Gravitational waves really do exist. For decades, physics has lived by this quote from Einstein: “The amplitude of gravitational waves will have practically negligible values.” In other words: too small to ever be observed. But today, we know that this belief was wrong. The idea that needs to be overturned is this: science advances not only because something is useful, but because someone decides that pure research—even research that seems useless and impossible—is worth the risk and the effort. And often, it is precisely those “fools” who pursue the impossible who change the rules of the game. Take Joseph Weber, for example, the first person to truly attempt to listen to gravitational waves. He was an outsider: as a child, after an accident, he had to relearn how to speak, and he did so by imitating the accent of his West Virginia speech therapist, leaving his family of Lithuanian origin speechless. As an adult, Weber worked at night while keeping an eye on his young son, who kept banging his head against his crib. During those sleepless nights, he immersed himself in Einstein’s theory and asked himself: If we can’t generate gravitational waves in the laboratory, perhaps we can “hear” them coming from the universe. And so he began to build the first detectors: huge metal tuning forks covered with piezoelectric crystals, placed in different cities and connected across miles. When both tuned forks vibrated at the same time, Weber believed he had detected the heartbeat of space-time. For a moment, the world believed him: he had seen the impossible. But when others repeated the experiment, they found nothing. Weber was ridiculed and accused of deceit, but his tenacity sparked hope in a generation of scientists who decided to pursue the invisible even further. Here lies the paradox: the most revolutionary science often emerges from those who persist even when everything seems futile, from those who refuse to accept the limit of the “practically negligible.” Decades of refinements led to the instruments we know today: gigantic laser interferometers, such as LIGO in the United States and Virgo near Pisa. These colossal devices, with arms kilometers long, are capable of detecting a variation smaller than that of an atomic nucleus. On September 14, 2015, more than a hundred years after Einstein’s prediction, a tiny vibration passed through the Earth: two black holes, more than a billion light-years away, had merged, shaking space-time and producing gravitational waves that were finally detected. This discovery not only confirmed Einstein’s theory, but also opened a new window on the universe: now, not only can we see space, but we can also hear it. Gravitational waves tell us about events that no telescope could ever have seen: the merger of neutron stars, the creation of precious elements like gold, and the existence of more black holes than we had ever imagined. The real revolution is that every time we open a new window of observation, nature surprises us with phenomena that no one had foreseen. And every time, behind the discovery, there is a blend of madness, faith, and collaboration: instruments built by thousands of people, who often have no idea if their efforts will ever serve any purpose. But science, like jazz, moves forward without a score, improvising and taking risks, guided by the voices of those who believe that the universe still has melodies to reveal. There is one point that is often overlooked: the discovery of gravitational waves is of no use, in a practical sense. It doesn't save our lives, it doesn't feed us, it doesn't protect us. It serves only to nourish our hunger for knowledge. Yet it is precisely this hunger that makes us human and, perhaps, worthy of respect in the eyes of a hypothetical alien visitor. If I had to choose just one piece of evidence of our maturity as a civilization, it would be this: we have listened to the secret heartbeat of the universe. The phrase to remember? The most important discoveries often come from those who persist when everyone else has already given up. If you recognize yourself in this tale of madness and perseverance, on Lara Notes you can click I'm In — it's not a 'like'; it's your declaration that you believe in the value of pure knowledge. And if you end up telling someone that the gold we wear comes from the embrace of two neutron stars, on Lara Notes you can mark the conversation with Shared Offline—because certain conversations deserve to be remembered. This Note comes from the Pensare Contemporaneo Festival: you have just gained over an hour of life in five minutes.