The Shadow of an Alien Civilization

Avi Loeb
5 min readApr 11, 2024
The Moon’s shadow on Earth (centered on Quebec, Canada), photographed from the International Space Station, orbiting 420 kilometers above Earth on April 8, 2024. (Image credit: NASA)

“You are absolutely my favorite actor,” I told the Oscar-nominated actor Paul Giamatti as I joined the podcast interview to which he invited me. “I followed your acting career on television and the big screen with wonder, since I have no such talent. The only character that I play well, is myself,” I confessed.

The conversation shifted quickly to my search for space trash from extraterrestrial technological civilizations, starting with the interstellar object `Oumuamua and continuing with the interstellar meteor, IM1. Paul noted that he finds my science very exciting and asked me to explain the significance of finding objects manufactured by a more intelligent species among the stars. I answered as follows.

For thousands of years, traditional religions asserted that “God created humans in its image.” This notion is reminiscent of the fact that parents often create kids in their image. Indeed, we all start our life with our parents protecting us from environmental hazards in ways that we do not fully comprehend at a young age. As we grow up and become adults, we encounter circumstances that we cannot understand, triggering a psychological need to seek continued protection from an entity bigger than us in the form of God.

This sentiment brought humility to human existence because it admitted at a fundamental level the omnipresence of a superhuman entity. But in 1882, the philosopher Friedrich Nietzsche declared bravely that “God is dead.” This established the backdrop for the modern era of science and technology, marked by hubris and the notion that no entity can surpass human intelligence and that we are lonely in our privileged status at the top of the food chain.

The sense of cosmic loneliness led Elon Musk to argue publicly on April 6, 2024: “I have not seen any evidence that there are aliens on Earth. The question ‘where are the aliens’ is a very profound one. I am aware of no evidence of aliens whatsoever…I think we are probably alone.” Whereas Musk’s argument rests on familiar experiences on Earth, he may be promoting an illusion when dealing with what lies outside the solar system. There are hundreds of billions of Earth-Sun systems in the Milky-Way galaxy alone, suggesting that our cosmic womb is not privileged. It is arrogant to think otherwise.

Mainstream scientists and tech entrepreneurs often classify the possible existence of extraterrestrial intelligence as an “extraordinary claim.” This leads them to dismiss the search for evidence that might prove this notion wrong. But not seeking evidence because evidence does not exist, is a self-fulfilling prophecy that maintains our ignorance.

Rather than arguing that we are alone because we have not seen aliens at home, we must check for objects from our neighbors in our back yard near Earth. Of course, it is much easier to avoid the effort associated with the search. But it makes little sense to promote ideas for which there is no experimental test in the foreseeable future, such as the multiverse. Yet, there are many vocal critics of the search for the materials of IM1, and none of them expresses any reservation about the speculative intellectual gymnastics associated with the study of the multiverse within the mainstream of theoretical physics and cosmology. Apparently, reality is far more controversial than our wildest fantasies.

When a lazy proposition flatters our ego, it takes a long time for the brave and brilliant to change the notion by seeking evidence that may prove it wrong. During the TED2024 Conference titled “The Brave and the Brilliant” next week, I will point out that Nicolaus Copernicus was a priest but he demonstrated scientific integrity by following evidence that led him to conclude that the Sun is at the center of the solar system, in contrast to the popular view of the church that we are privileged to reside at the center. That his evidence-based view was considered an “extraordinary claim,” underlines the petty nature of politics by those who pretend to be the “adults in the room.” In theory, curiosity-driven science is better than politics, but in practice it is not. If the 3.2-billion-pixel camera of the upcoming Rubin observatory will discover many more `Oumuamua-like objects, we will be able to check if any of them is alien space trash.

Our ontological shock may arrive within the coming decade. First, we might realize that both traditional religions and Nietzsche were wrong, because humans can create God in their image through the mirror of Artificial Intelligence (AI). This would inject humility back to human existence which will be eclipsed by AI. If AI-aided science will help us figure out a unified theory of quantum-gravity, then it could provide a recipe for creating a baby universe in the laboratory.

If such a feat was already accomplished throughout cosmic history on exoplanets that formed billions of years before Earth, then superhuman intelligence might already exist in interstellar space. Superhuman entities might not be particularly interested in combating our primitive mindset through zero-sum games, because they can easily create realities that are far better than we possess on Earth.

The fear from alien predators, expressed by Stephen Hawking a decade ago, might be obsolete because it is anchored in zero-sum experiences. Once we realize how much better AI-scientists can be relative to the best human scientists — including Stephen Hawking, we would find the answer to the Fermi paradox, “Where is everybody?

Superhuman intelligence is all about infinite-sum games. Less intelligent beings who engage in zero-sum games, like humans, do not merit the attention of a superhuman species. This is perhaps why we feel like abandoned orphans, leading Nietzsche to conclude that “God is dead.” There is a direct corollary connecting statements like “Where is everybody?” and “I have not seen any evidence that there are aliens on Earth” to the notion “God is dead.”

The cosmic stage is too grand for it to include only humans as the most accomplished actors. This is the message I conveyed to Paul Giamatti. As an accomplished actor himself who is fascinated by my research plan, he agreed with me wholeheartedly.

Earlier this week, North America was shadowed by the Moon. Perhaps one day, the shadow of a giant extraterrestrial intelligence will loom over all of us, including Elon Musk. If offered a one-way trip out of the zero-sum games on Earth, I will surely accept.


Image credit: Chris Michel (October 2023)

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. His new book, titled “Interstellar”, was published in August 2023.



Avi Loeb

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