By now, I have published over a thousand peer-reviewed scientific papers and four professional textbooks, chaired the Harvard Astronomy department for nine years, served as director of two research centers — the Black Hole Initiative and the Institute for Theory and Computation — for two decades, and chaired the Board on Physics and Astronomy of the National Academies. Naively, one would think that when I write an out-of-the-box scientific paper on a mainstream topic like black holes, it would be welcomed with great interest by the academic community. Not so.
Let me start with the scientific context for my latest paper.
There are numerous discussions in the astrophysics literature about the accretion of matter onto black holes. This is the process that powers the supermassive black holes — known as quasars — at the centers of galaxies, or the stellar-mass black holes with a donor star companion that feeds them with matter. The mouth of black holes is their event horizon, ranging between the size of the solar planetary system in the galactic case down to the scale of a city in the stellar case. Given the large size of these mouths, infalling matter can be approximated as a continuous fluid, ignoring its granular composition as elementary particles, such as electrons, protons, atoms or molecules.
There is another class of black holes that is extensively discussed in the astrophysics literature. It involves mini black holes that could have formed as a result of local enhancements in the radiation density on cosmic horizon scales in the early universe. These primordial black holes can account for the unknown nature of dark matter if they possess a mass between a billion to a hundred trillion tons, similar to the masses of asteroids with a diameter in the range of 1–100 kilometers.
A month ago, I realized that the event horizon of primordial black holes with these masses is in the range between the sizes of nuclei and atoms. A classical black hole is the ultimate prison, but it is difficult to fit a plump prisoner into a prison that is smaller than the prisoner’s body size. According to quantum mechanics, all elementary particles have a characteristic size, dictated by their momentum. This size is the so-called de Broglie wavelength, derived exactly a century ago in the 1924 PhD thesis of the Nobel laureate, Louis de Broglie. It occurred to me that particles with a de Broglie wavelength bigger than the event horizon of primordial black holes could not be easily swallowed by these holes.
Since the corpuscular nature of matter is important here, the infalling matter cannot be approximated as a continuous fluid. I calculated the resulting suppression in the accretion rate both for free electrons as well as for bound states of electrons around a charged black hole.
Since the results appeared straightforward, I submitted my short paper as a preprint to the astrophysics arXiv and as a research note to an online scientific journal. The arXiv moderators blocked the posting and the research notes’ editor replied that this submission should be sent to a different outlet with “an appropriate peer reviewer who could comment on the physics.”
I considered submitting the note to the excellent Journal of Cosmology and Particle Physics (JCAP) where I served as editor for many years, but the submission form requires the arXiv identifier for the related preprint, which I did not have because the arXiv moderators blocked the preprint. And so, I decided to submit the paper to the prestigious Astrophysical Journal Letters, which has the highest impact factor of all astrophysics journals worldwide.
After a few weeks, the arXiv moderators allowed my paper to be posted online. Keep in mind that the arXiv gatekeepers are not supposed to review papers. In a more extreme case this month, the arXiv moderators declined to post a different paper I wrote on novel gravitational wave signals even after I submitted a petition arguing that my paper was published with a DOI number in Research Notes of the American Astronomical Society. For several weeks, the dissemination of my results on the quantum-mechanical suppression of accretion by primordial black holes was blocked for an unexplained reason. My paper is six pages long and its online posting has a minimal carbon footprint. But the scientific community did not know about my work until I mentioned it in a Medium.com essay, where I have nearly 50,000 followers.
In response to this essay, I received an email from the brilliant physicist, Paul Davies, who informed me that he wondered about the same problem half a century ago and asked John Wheeler who told him that his student at the time, Jacob Bekenstein, is thinking about the same problem. In the end, no related paper addressed this problem since then, and Paul wondered whether I have written my thoughts. At the same time, I received another email from the exceptional physicist, Moti Milgrom, who also did not know about my paper since the arXiv blocked it.
After my preprint on primordial black holes was finally posted online, a physicist whom I never interacted with, posted a single page scathing criticism of my preprint with merely two paragraphs of superficial text. This preprint was posted on the arXiv immediately with no moderation. My daughter interpreted this as a good sign because based on her reading of social media, all celebrities have haters. At the opening of my class on `Radiative Processes in Astrophysics’, I commented that the strongest force in academia is not electromagnetism but jealousy.
The good news is that The Astrophysical Journal Letters editor did a fantastic job in selecting a highly-qualified reviewer for my paper. The review was insightful and helped improve the quality of my paper. Yet, I keep thinking about all the unborn babies, those innovative ideas that were not as lucky as mine to be shared with the scientific community.
Yes, there is light at the end of the academic tunnel. But is the light in today’s academia sufficient to support a fledgling young scientist who came up with a new theory of special relativity in a Swiss Patent Office at Bern? I am not that confident.
For the related scientific paper, click here.
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.
