The Difference Between Scientific Research and Social Media Opinions
Cosmic-rays are energetic charged particles that permeate the solar system, reaching Earth with energies between the rest-mass of the electron and up to a quadrillion (10^{15}) times more (as reviewed recently here). The highest energy particles with more than 10,000 times the electron rest-mass, originate mostly outside of the Solar System, either in the Milky-Way Galaxy or the Universe at large. Less energetic particles are also produced by the Sun. Most of the cosmic-rays arriving from outside the Solar System are protons and helium nuclei but they also include heavy nuclei. These energetic particles are produced throughout the cosmos in explosions of stars or by energetic processes in the vicinity of compact objects like black holes or neutron stars.
Cosmic rays were discovered in 1912 through balloon experiments carried out by Victor Hess, who received the 1936 Nobel Prize in Physics for his finding.
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Three essays ago, I wrote an essay (posted here) in which I suggested that the mysterious blue lights observed in Apollo camera images of the Moon were likely cosmic rays because they appeared in the photographic film outside the region exposed to the camera lens. Cosmic-rays might also account for the light flashes reported by the Apollo astronaut Buzz Aldrin, since charged particles that move faster than light in a water-based medium like Aldrin’s eyeballs, generate blue Cherenkov radiation — analogous to the shock wave produced by a supersonic jet. These Cherenkov light flashes are observed by patients who go through radiotherapy, as reported here.
It is therefore entirely reasonable to propose that the reports on flashes of light from the Apollo mission in the UFO files released by the Department of War here, were in reality triggered by cosmic-rays rather than UFOs. The intensity of cosmic-rays is known to be 200 times larger outside the protective atmosphere and magnetosphere of Earth than on the surface of Earth.
The second part of my essay calculated that on average about 60,000 energetic particles must have hit the emulsion of each photographic plate from the historic Palomar Sky Survey, given the plate surface area and the hour-long duration of the exposure. This cannot be disputed since we measure the hit rate of cosmic-ray secondaries on the ground. The interaction of cosmic-rays with the Earth’s atmosphere produces a cascade of secondary particles called Cosmic Ray Showers, which include leptons such as: muons, electron-positron pairs and neutrinos, hadrons such as: protons, neutrons, kaons, charged and neutral pions, as well as high-energy photons (gamma-rays).
It is well-known that the particles from cosmic-ray showers appear as transient smudges on all recording devices in astronomy. Depending on their incidence angle, their recorded spots look like thin bright streaks or point-like transients which are impossible to avoid. In the CCD and CMOS devices of digital cameras, a passing cosmic-ray (typically a muon) saturates a trail of pixels. If the particle hits the sensor directly from above, it appears as a bright, compact “star-like” spot. If it strikes at an angle, it leaves an elongated streak, line, or “worm”. In photographic plates or historical films, cosmic-ray impacts show up as dense, lines or small star-like dots that can be mistaken for uncatalogued asteroids or transient phenomena. When a cosmic ray passes through a photographic plate emulsion, it ionizes the silver halide crystals. Upon chemical development, these energized grains are reduced to dark metallic silver, revealing the particle’s trajectory and interactions.
Astronomers treat cosmic rays as “noise” in standard imaging, because they can ruin exposures. Automated calibration and stacking software rely on algorithms to identify and remove cosmic-ray tracks from deep-sky images (as discussed here).
It therefore goes without saying that point-like transient sources recorded on photographic plates in the Palomar Sky Survey could be contaminated by cosmic-ray events.
Cosmic-ray events should be anti-correlated with geomagnetic storms because coronal mass ejections from the Sun carry magnetic fields and deflect cosmic-rays away from Earth. Such forbush decreases in cosmic-ray hits during geomagnetic storms are well documented, as discussed here. Given that an anti-correlation with geomagnetic activity was reported here in the context of UFO transients in the Palomar plates, it only makes sense to examine whether the transient events are the result of cosmic-rays rather than UFOs. Why would UFOs be sensitive to coronal mass ejections? It is more reasonable to interpret this detected anti-correlation as evidence that the transients originate from cosmic-rays which are known to be anti-correlated with solar storms.
Since the primary cosmic-ray flux is composed of charged particles, it is expected that any magnetic irregularity or turbulence affects their large-scale transport and consequently their energy spectrum on Earth. Through its journey towards Earth, the cosmic-ray flux is modulated inside the heliosphere by the interplanetary magnetic field and the solar wind, which vary according to the Solar Cycle.
Nuclear explosions on Earth also produce energetic particles, and one wonders whether these particles might have also been recorded on the Palomar plates to produce the reported correlation of UFOs with nuclear tests.
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The possible association of energetic particles with historical transients sparked an avalanche of hate messages from those who firmly believe in the UFO interpretation of transients recorded on the Palomar plates. But the reality is that cosmic-ray impacts will not go away just because these believers dislike them.
Scientific research is based on the sober recognition of the physical reality that surrounds us. It does not matter how many times and for how many years we express our beliefs on social media. The Sun did not start going around the Earth just because the Vatican advocated that notion firmly for centuries, and placed Galileo Galilei in house arrest for claiming otherwise based on telescope data. Cosmic-rays must have hit the Palomar plates in the 1950s and some of them must have appeared as point-like transients just like the claimed UFOs. The only question is whether the noise they inevitably introduced is smaller than the signal detected.
Cosmic-ray transients could have clusters or deficits. The number of cosmic-ray hits which are recorded on each plate would depend on the orientation of the telescope relative to the sky and the geometry of any protective segments of metal within the telescope. This could give rise to a spurious association with the Earth’s shadow. Confusion with bright solar system sources such as asteroids, comets or planets or with background stars in the Milky-Way disk, could cause deficits in the reported cosmic-ray transients in the ecliptic plane or in crowded star regions.
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Let me make it absolutely clear. Scientific research is not about detecting signals but about removing the noise in order to gauge whether the signal is statistically significant and not just noise.
The noise of cosmic-rays masquerading as transients will not be removed by hate messages on social media. The only way to find out whether historical point-like transients are real or not is to find them again today in new images from the 3.2 gigapixel camera employed by the NSF-DOE Rubin Observatory — which is far superior relative to the Palomar Observatory camera. There is no reason why UFOs would be recorded only by Apollo astronauts on photographic films and not by the excellent digital cameras used by the Artemis II astronauts last month. There is no reason why UFOs will appear in the Palomar Sky Survey and not in the Legacy Survey of Space and Time (LSST) of the Rubin Observatory.
Instead of capitalizing on hate messages, we should all get used to treating science as a learning experience and work in progress.
Interestingly, I find dogmatists — namely zealots who claim to know the answer in advance — among practicing scientists as well as among UFO believers. Both have the tendency of sending hate messages in my direction.
Before engaging in my morning jog at sunrise, I decided to reply to both with the following message. Lets all be curious and figure out the truth from higher-quality evidence that we collect in the future. The problem with past reports is that we cannot go back in time and get better data than we were given by inferior instruments relative to those we have today. We have the opportunity to do better with our current sensors. Rather than wait for the Department of War to tell us what lies in the sky based on past reports, we can simply look up with better instruments. This is the goal of the Galileo Project under my leadership.
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.
Professional website:
https://lweb.cfa.harvard.edu/~loeb/
Social media:
https://avi-loeb.medium.com/
https://www.youtube.com/@ProfessorAviLoeb
https://open.spotify.com/show/1zhndXkvSY2b8FdjspFpCd
https://x.com/ProfAviLoeb
