During an interview for the Boston Globe, the reporter asked me whether working on the new frontier of interstellar objects in search for extraterrestrial gadgets resulted in a different experience than my academic work on other topics. I replied that I approach all scientific matters the same way. Unlike the political matters addressed by University presidents in Congress last December, the scientific method does not depend on context.
In all scientific matters, science is based on proposing theoretical hypotheses, collecting evidence, analyzing the data and interpreting it as a test of the proposed hypotheses. If the data stands in conflict with all existing theories, it is regarded as anomalous, potentially requiring a conceptual revolution.
I started my career in cosmology, when it was encouraged to hypothesize possible candidates for the invisible matter that makes 83% of the matter in the Universe. Since we do not know what dark matter is, any credible proposal, like primordial black holes or weakly-interacting massive particles, inspired new experiments that searched for signals of these hypothesized entities, including gravitational lensing in the first case or rare events in finely-tuned laboratory set-ups in the second case. Over the past thirty years, billions of dollars were invested in testing theoretical ideas about dark matter, most recently through the search for the lightest supersymmetric particle by CERN’s Large Hadron Collider, without success. This heroic effort defines the way science is done at its best. The endless pursuit of new scientific knowledge should never be ridiculed, irrespective of context.
For that reason, when dark-matter anomalies were pointed out at the centers of dwarf galaxies, I published a paper in Physical Review Letters with Neal Weiner suggesting that dark matter particles may have strong electric-like interactions with each other but not with ordinary matter. This proposal was cited by 317 subsequent papers and studied thoroughly with computer simulations that compared its implications to new observational data. The hypothesis did not receive much media or public attention. However, when I suggested in the same spirit that the first two interstellar objects, `Oumuamua or the meteor IM1, might be technological in origin, I approached their anomalies in the same way as the nature of dark matter. At first, my resulting theoretical hypothesis was welcomed by colleagues or reviewers. But as soon as they attracted media and public attention, the hypothesis was aggressively ridiculed by a group of vocal critics. In effect, these naysayers are criticizing the scientific method.
The reporter wondered: “Why are they doing that?”, and I explained that members of academia are strongly interacting. The force is not mediated by photons or gluons. It is the force of jealousy, driven by media attention. However, from the point of view of communicating the excitement of science, public attention reflects interest which is a virtue, not a bug. Given that society funds science, it is the duty of scientists to address questions that the public cares about. Most science is engaged with concepts that are removed from daily life, like the nature of dark matter, and so scientists get a pass in avoiding societal feedback. But these common circumstances, like in the case of my work with Neal Weiner, should not imply ridicule when a hypothesis excites the public. The tension created by public interest should be relaxed for the same reason that asking whether dark matter is strongly interacting should not be avoided if it receives millions of likes on social media.
In short, my approach to studying matter from outside the solar system does not depend on whether it is a technological gadget or exotic dark matter. It does not depend on context.
Consider a historic perspective. Scientists did not believe that stones could fall from the sky until 1803, when 3,000 pieces of rock rained on the French town of l’Aigle. The physicist Jean-Baptiste Biot went there to collect evidence from real witnesses. Biot believed in the power of science communication, and his literary report on the l’Aigle meteorite fall received broad attention from the media and public.
But the story has a twist. The physicist Ernst Chladni published a book in 1794 suggesting that meteorites came from space. Chladni hesitated to publish his hypothesis, according to an insightful paper by the historian Ursula B. Marvin, because Chaldny knew that he was “gainsaying 2,000 years of wisdom, inherited from Aristotle and confirmed by Isaac Newton, that no small bodies exist in space beyond the Moon.”
Today, my critics insist that interstellar objects must be natural in origin. They argue that the anomalies of `Oumuamua imply abundant objects of a type that we had never seen before, like hydrogen or nitrogen icebergs. They dismiss the search for technological objects among interstellar rocks, even though they know about the five spacecraft that NASA launched out of the Solar system and the Tesla Roadster that Elon Musk launched to an elliptical orbit around the Sun, extending beyond the orbit of Mars.
To sideline a hypothesis just because it attracts public interest is a step away from evidence-based science, deterring scientists like Chladni from a hypothesis that ends up describing reality. To insist today that interstellar meteors must be stones is no different from denying that meteors are stones before 1803.
My interview took place on the same day when I posted two new papers online: one paper about the threat to astronomical sky surveys from space debris of broken satellites or rocket pieces, and the second paper about the hypothesis that at early times the Universe expanded differently in different directions. During the hours preceding the interview, I received two dozen emails from colleagues who were excited about both papers. Rest assured, as long as the Boston Globe will not report about these papers, their content will not be ridiculed.
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.
