When Visiting the Jungle, We Are Likely to See Animals

What makes common sense different from insanity? Knowing what is reasonable to expect under the circumstances. If something unexpected is found, we must demonstrate that it cannot have a mundane explanation before we catalog it as an outlier. In particular, a signal must be significant relative to the noise level. Prior to calling it extraordinary, we need to exclude the possibility that it is an ordinary consequence from the environmental background. This step of excluding the ordinary is essential for learning something new. Without it, we learn nothing new because the ordinary is not excluded.

When visiting the jungle, we are likely to see animals. When embedded in a war zone, observers are likely to see artillery shells or bullets fired by machine guns. Therefore, astronomers at the Kiev Observatory who detect dark objects in the sky above Ukraine during war time, should not draw analogies with Unidentified Aerial Phenomena (UAP) from the ODNI report to the US Congress — which were regarded as extraordinary because they were unexpected under peaceful circumstances. The astronomers must first show beyond any reasonable doubt that the objects they notice in the sky above Ukraine cannot be the products of a military conflict. For example, when they report in their paper the detection of a luminous and variable object at an altitude of 1,170 kilometers above Ukraine, they must exclude the possibility that it is a satellite before labeling it as a UAP.

This is common practice in science. Before claiming a signal, a scientist must rule out the background noise. For example, before claiming that the B-mode polarization of the cosmic microwave background originates from the first instant after the Big Bang, one must rule out the contribution from local interstellar dust. The BICEP/Keck team is engaged in a heroic effort to constrain cosmic inflation from the distant past by removing the detected polarization signal from dust in our Galactic backyard. Before claiming something new, experimentalists must spend a huge effort in measuring the background noise level which could account for their signal. This is dictated by common sense.

The same holds in reverse: if experimental data shows beyond a reasonable doubt an extraordinary finding, then this finding should not be labeled as ordinary just to maintain the psychological comfort of experts. Those who gained their self-esteem from past knowledge will tend to resist new knowledge, because it threatens their status among professional peers. For example, `Oumuamua was not an ordinary comet because it did not have a cometary tail of gas and dust based on deep observations by the Spitzer Space Telescope. It also had an extreme shape and was pushed away from the Sun like another object, 2020 SO, discovered in September 2020 by the same Pan STARRS telescope. The other outlier 2020 SO exhibited a push by solar radiation pressure with no cometary tail and later found to be made of stainless steel and identified as the defunct rocket booster, Surveyor 2, launched by NASA in 1966. Many comet-experts still call `Oumuamua a comet, just so that they would not need to admit within their community that the first reported interstellar object was extraordinary. This is like going to the jungle and labeling a monkey “an unusual cat”, just because cats carry a more familiar and comforting connotation to the community of people outside the jungle.

The Main Astronomical Observatory in Kiev of the National Academy of Sciences of Ukraine issued the statement that: “… the processing and interpretation of the results was done at an inadequate scientific level and with significant errors in determining the distance of the observed objects.“ This statement confirms the conclusions of the paper I posted independently last week, in which I showed that the properties of the dark objects suggested by the Ukranian astronomers would inevitably result in bright fireballs as a result of their atmospheric friction and violate their dark nature. But if the distances were overestimated by a factor of ten or more, then the dark objects would match the sizes and speeds of artillery shells or machine gun bullets.

The fireball argument raised a lot of chatter by UAP advocates on Twitter. In my view, dark objects that block particles of light must also block particles of air because both processes are mediated by the same electromagnetic interaction. Common sense implies that the electric and magnetic fields of light are no different from the electric and magnetic fields of charged particles in the Earth’s atmosphere. An object cannot respond to one and not the other because they are of the same electromagnetic nature.

In the court of law, people are convicted of crimes and sentenced to jail based on eyewitness testimonies. However, scientific evidence is held to a higher standard. For a scientific claim to be regarded as credible, it must be based on quantitative data from instruments that are fully understood and under control along with the sources of noise from the environment they are embedded in. The significance of a signal is measured by how much it exceeds the level of the noise, the so-called “signal-to-noise ratio”. In contrast to measurement devices, eyewitness testimonies could be biased by wishful thinking, hallucinations, ulterior motives, or insufficient attention to background noise. As Winston Churchill noted, history depends on who writes it, making it challenging to extract a balanced description of the physical reality based solely on reports from humans. Aside from unrecognized environmental noise, humans could be misled by systematic effects. For example, humans can be fooled by seeing multiple objects that come in and out of view at different places and thinking that they are the same object and therefore moving extremely fast. They could also be deceived by optical illusions.

The Galileo Project that I lead, takes a scientific approach to UAP research that is based on specially designed scientific instrumentation. Tweets or blog posts will not change the scientific method, pioneered by Galileo Galilei, after whom our project is named.


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.



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Avi Loeb

Avi Loeb


Avi Loeb is the Frank B. Baird Jr Professor of Science and Institute director at Harvard University and is the bestselling author of “Extraterrestrial”.