“If a tree falls in a forest and no one is around to hear it, does it make a sound?” No, if reality is defined by social media.
However, those of us who are curious enough to seek evidence from the real world, say to those of us who live in the virtual world: “There are more things in heaven and Earth…than are dreamt in your philosophy,” as Hamlet told his friend Horatio in Shakespeare’s play. Our imagination is limited by our past experience on Earth, and what happens far away may be a completely different story.
If we ever find an interstellar tennis ball, we will know that our cosmic neighbor plays tennis. But most likely our first encounter with a product of superhuman intelligence would be an object that my colleagues would describe as “a rock of a type that we had never seen before.” This was said about the first reported interstellar object, `Oumuamua, and might be said about similar outliers to be discovered by the 3.2 gigapixel camera of the Rubin Observatory, starting in 2025.
If a spacecraft sails through the Solar system and no astronomer notices it, surely it exists. That our ignorance is bigger than our knowledge should make us all curious about what we might be missing. There are the `known unknowns,’ such as the nature of dark matter and dark energy which combine to make 95% of the cosmic mass budget at the present time. But there are also the `unknown unknowns,’ in the words of the former Secretary of Defense Donald Rumsfeld. This category could include stealth technologies that avoid detection by our telescopes because they use physics beyond our standard model. It is difficult to forecast the `unknown unknowns’ because the range of possibilities is vast.
A hint that we are missing something typically stems from the detection of an anomalous phenomenon. Without being curious enough to study it, we will never realize what we might be missing. Indeed, experts suffer from a cognitive dissonance in the face of anomalies. This led a colleague of mine to say: “`Oumuamua is so weird, I wish it never existed.”
Of course, there are many anomalies that reflect limited data, statistical fluctuations or mundane explanations. These can be resolved by obtaining better data. In an interview that I had yesterday with Dick Russell for his new book, he asked: “how would you be able to prove yourself wrong about an exotic interpretation of an anomalous object?” I replied with the simple answer: “by collecting better data.” If we had the privilege of landing on `Oumuamua, we could have easily determined whether it is a rock or a light sail. If our future expedition to the Pacific Ocean will find a large relic of the interstellar meteor IM1 near its fireball site, we could easily infer its nature. When data is limited, curious scientists must keep all possibilities on the table until proven wrong, because this motivates them to collect better data. On the other hand, those who use science as a tool to promote their ego, insist that they know the answer in advance and argue against the need to seek evidence. When someone else pursues the hard work of collecting materials from IM1’s site, they would raise doubts on whether this endeavor is worthwhile. Science journalists who seek clickbait would amplify their doubts, but remain silent when a detailed scientific paper on the actual scientific results is peer-reviewed and published. In the words of one of these journalists: “We prefer not to confuse our readers…,” to which I would add: “with facts.”
Science can be exciting, as long as it follows curiosity and is not blocked by gatekeepers. My recent TED talk triggered invitations to four major engagements with the public and numerous messages from kids who were inspired to become scientists. There is a fundamental difference between practicing science and talking about others who practice it. In today’s landscape of social media and journalism, there are many who pretend to serve as ambassadors of science, even though they did not publish a single scientific paper over the past decade.
We should give priority to those who practice science. The reason is simple: scientific discoveries are unexpected. Only practitioners of science can collect the data or write the equations that unravel new discoveries, for the same reason that only players on the soccer field, and not sport commentators, can score a new goal.
The power of science is in the ability of new data to convince us that we missed something important. If a spacecraft roars through the solar system, the curious scientists who will analyze data from the pipeline of the Rubin Observatory might notice it. If not for them, we might all continue to believe that such spacecraft do not exist. We do not need to imagine what we might find but rather search for the unfamiliar.
But most importantly, we need to free ourselves from prejudice and agree that it is worthwhile to invest time in searching for the unexpected. In 1952, the Ukrainian-American astronomer, Otto Struve, suggested a method to search for a close-in, hot Jupiter around a Sun-like star. His suggestion was ignored by observers for four decades because they believed that there is a good physical reason for why Jupiter must reside far from the star, as observed in the Solar system. Struve died in 1963. In 1995, Michel Mayor and Didier Queloz discovered the hot Jupiter 51 Peg b. They neglected to cite Struve in their paper. Mayor and Queloz were awarded the Physics Nobel Prize in 2019. It would have been fitting for Struve to join them if he were alive, because he imagined what they discovered. As Albert Einstein noted: “Imagination is more important than knowledge. For knowledge is limited to all we now know and understand, while imagination embraces the entire world, and all there ever will be to know and understand.”
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 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. The paperback edition of his new book, titled “Interstellar”, was published in August 2024.
