There Are No Illegal Aliens in Interstellar Space

Avi Loeb
4 min readSep 3, 2024

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(Image credit: NBC News)

The Preamble of the U.S. Constitution acknowledges the “Blessings of Liberty.” There is no greater privilege on Earth than the freedom from political prosecution, imprisonment or slavery. But wouldn’t we be even freer if we escaped Earth?

One might imagine absolute freedom as the privilege of a lone pilot on a craft flying through interstellar space. Out there, nobody limits the pilot’s liberty, because the spacecraft flies outside the territorial border or legal jurisdiction of anyone else. There are no illegal aliens in interstellar space.

Naively, this setup might appear like the ideal manifestation of the blessings of liberty. But in reality, the dark scenery of interstellar space during a lonely journey that takes thousands to billions of years to complete, makes the experience worse than imprisonment. A typical prison on Earth offers a much richer environment with more opportunities for thrills, than the rarefied ambience of interstellar space.

Taken to the extreme, the ultimate expression of liberty in a spacecraft would feel no different than solitary confinement in a lonely prison cell. Both are characterized by complete isolation.

There are even worse circumstances, of course. Entering the event horizon of the nearest supermassive black hole, Sgr A*, would feel like solitary confinement, except that this experience would last only 7-minutes before the traveler’s body would be ripped apart by the tidal force from the 4-million solar mass singularity. Nature has its way of limiting suffering under solitary confinement with a mandatory death sentence, executed by gravity’s tidal guillotine.

The lesson from this thought experiment is simple. Humans thrive under a balanced dosage of freedom and constraints, but removing one of these necessary ingredients creates unhappiness. Societal constraints serve an important role, similar to the role of air in creating friction but allowing birds to fly by flapping their wings.

Our freedom is expressed in the way we overcome societal constraints. Absent of friction with society, freedom is as meaningless as music with no sound. John Cage created the empty musical composition titled 4′33”, first performed on August 29 of 1952. It consisted of three movements of silence, lasting 33 seconds, 2 minutes and 40 seconds and 1 minute and 20 seconds, respectively. A lone pilot on an interstellar journey could listen to Cage’s composition for billions of years with no need for an orchestra.

But there are better alternatives. Humans can travel away from Earth in groups with an optimal balance of liberties and constraints, sharing artificial space platforms or natural moons and planets.

For the foreseeable future, it is far more economic to venture into interstellar space in small craft navigated by artificial intelligence (AI). AI systems do not need to be stimulated by societal constraints in order to thrive. With proper technological design, they can survive the solitary confinement of an interstellar probe.

This suggests that we are unlikely to encounter biologics in crash sites of extraterrestrial craft. The possibility that the government may have alien biologics in its possession, as recently claimed by former government officials David Grusch and Lue Elizondo, must be substantiated by material evidence in order to be scientifically viable. Such evidence was not shared with the public as of yet.

It is straightforward to date the age of a few grams of material from a biological body or a craft and test whether it is different from the age of the Solar System. This does not require identification of genetic material. In fact, alien life may be structured differently than the DNA of lifeforms on Earth, which all started from the Last Universal Common Ancestor (LUCA), 4.2 billion years ago. Instead, scientists can study abundances of rare isotopes and their decay products to date the age of the recovered materials, irrespective of the biological nature of alien life forms.

These are exciting times, since astronomers identified interstellar objects for the first decade in human history. The Galileo Project is busy analyzing results from its new observatories, and the Galileo research team is seeking funding for the next expedition to retrieve large pieces from the first recognized interstellar meteor in the Pacific Ocean.

Surprises are possible. Finding a lone biological pilot in an interstellar craft would suggest that either aliens are extremely patient and long-lived by our standards, or that their craft traveled at an extraordinary speed, thousands of times faster than our rockets. Both possibilities would be shocking.

Based on our terrestrial experience, AI pilots are expected to be far more abundant than biological pilots in interstellar space. Nevertheless, we should remain open minded to material evidence. All in all, our freedom of inquiry is in part fulfilled when we learn something new.

ABOUT THE AUTHOR

(Image credit: Chris Michel, 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.

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Avi Loeb

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