The absolute silence dominated my routine jog this morning along an empty path, with the rising sun as my only companion. I was struck by how lonely we can be in the company of physical objects, even as magnificent as this giant fusion reactor situated 8.33 light-minutes away. This sense of loneliness with a lack of spiritual purpose reverberates throughout the cosmos. Near the end of his book “The First Three Minutes”, the distinguished physicist Steven Weinberg, noted: “The more the universe seems comprehensible, the more it also seems pointless.”
To recognize the level by which physical reality bites, let us recap some well-known facts. No human lived for more than one part in a hundred million of the time that elapsed since the Big Bang. Our news cycle is consumed by what happens on our terrestrial rock, a residue containing three millionths of the mass of the Sun — which was born in the last third of cosmic history. Our star, which enables all forms of life-as-we-know-it, contains merely a trillionth of the mass of the Milky Way galaxy, which by itself makes a part in ten billion of the mass enclosed within the observable volume of the Universe. To add insult to injury, the remarkable uniformity of the cosmic microwave background, left over from the Big-Bang, implies that there is no edge to the cosmos at least out to a distance 4,000 times bigger than our cosmic horizon. This means that there are at least 64 billion (4,000 cubed) more galaxies than those observable in the deepest images of the Webb telescope.
Similar to space, our ignorance also has no known limit. We do not know what happened before the Big Bang, so cosmic history could have extended well beyond our experience, making our existence even less significant in the grander scheme of things. Given this perspective, the Copernican realization that Earth is not at the center of the observable Universe pales in comparison to the realization that our cosmic existence is pointless.
With this humbling backdrop hanging over our head, the possibility that we might be the only intelligent species gives us existential comfort. Our pride stems from our intellectual superiority relative to other natural species on Earth. The emergence of large-language-models of artificial intelligence (AI) with more connections than the number of synapses in the human brain, might bring us back to the sober realization that human intelligence is not the pinnacle of creation. If our technological products might be smarter than we are, who is to say that there are no others out there who are even smarter?
As of now, most of my academic colleagues argue that that the notion that we are not alone in the Universe is an “extraordinary claim” that requires “extraordinary evidence”. However, my common sense argues exactly the opposite: it is extraordinary and arrogant for us to assume that we are special.
Over the past seven decades, the Search for Extraterrestrial Intelligence (SETI) focused on detecting electromagnetic signals. As the Drake equation implies, these may be rare if technological civilizations are short-lived. The breaking news are that interstellar objects were discovered near Earth over the past decade, and the first two: the interstellar meteor, IM1 — detected in 2014, and `Oumuamua — detected in 2017, appeared anomalous compared to familiar solar-system rocks. Their surprising appearance is a wake-up call that we must engage in an extensive search for interstellar objects near Earth. Only after we find thousands of interstellar objects to be merely natural rocks — can we start believing that Voyager 1 & 2, Pioneer 10 & 11 and New Horizon might become the first technological probes in interstellar space — once they will exit the Oort Cloud in ten thousand years. The search for interstellar objects is a win-win endeavor, because even if none of the interstellar objects we characterize are technological in origin, we will still learn something new about a diverse set of natural astrophysical environments that sent rocks in our direction.
The obstacles to gaining new knowledge about our cosmic neighborhood are twofold. First, there are “believers” who make unsubstantiated claims and sometimes forge evidence. Second, there are “debunkers” who are determined to refute related data and make no attempt to collect rigorous evidence based on the scientific method. Both sides energize each other and prefer the lazy approach of having an opinion without investing time and effort in assembling high-quality scientific data. If they were to win, we would be left ignorant.
Traveling to the Pacific Ocean for two weeks to retrieve millimeter-size spherules that melted off the surface of IM1 and settled on the ocean floor at a depth of 2 kilometers across a ten-kilometer region, and analyzing these spherules by a state-of-the-art mass spectrometer at Harvard University for two months, was hard work that culminated in a 44-pages-long scientific paper. Tweeting superficially about the findings was an easy escape route for all the naysayers who chose to behave unprofessionally and harass our research team for following the scientific method.
In the imagined reality of cosmic loneliness, our cosmic significance is self-declared. We can ignore packages in our backyard by not searching for them or by ridiculing any search made by the true scientists among us. But irrespective of what some of us tweet, an objective observer of IM1 or `Oumuamua would repeat Galileo’s words: “E pur si mouve” (and yet it moves).
My second important point is that finding interstellar senders would bring a meaning to our meager cosmic existence. In our personal life, finding a partner often gives us meaning because it channels existential sentiments back to us, providing us comfort. And this comfort is better than that afforded by arrogance and loneliness. The sense of pointlessness brought by comprehending the Universe must have resulted from the focus of cosmologists on lifeless entities, like elementary particles or radiation. If we find a partner out there, the cosmos might not be pointless anymore.
Here’s hoping that interstellar packages will bring us new scientific knowledge. If we ever communicate with extraterrestrial intelligence, the two urgent questions on my mind are: “What happened before the Big Bang?” and “Where is the nearest party of our neighbors?”
ABOUT THE AUTHOR
Avi Loeb is the head of the Galileo Project, founding director of Harvard University’s — Black Hole Initiative, director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, and the former chair of the astronomy department at Harvard University (2011–2020). He chairs the advisory board for the Breakthrough Starshot project, and is a former member of the President’s Council of Advisors on Science and Technology and a former chair of the Board on Physics and Astronomy of the National Academies. He is the bestselling author of “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth” and a co-author of the textbook “Life in the Cosmos”, both published in 2021. His new book, titled “Interstellar”, was published in August 2023.
