Exceeding the Escape Velocity is a Sign of Intelligence

Avi Loeb
5 min readMar 17, 2024


Falcon 9 launch of 60 Starlink satellites. Image credit: SpaceX

When my grandfather decided to leave Nazi Germany in 1936, his 65 family members argued that there was no need to rush. They were confident that their undeniable patriotism would save their lives and reasoned that in the worst-case scenario — they would leave on the last train. And so, they did. But that last train led to concentration camps where they all died. In other words, they did not exceed the escape velocity from their dire historic circumstances, because of poor strategic planning.

Fast forward to today. I am named after my grandfather, Albert Loeb (as Avi is short for Abraham, which is equivalent to Albert in German), and I proudly carry his insight. I would never wait for the last train because it may lead elsewhere. What does this lesson imply for me beyond paying attention to an alarming rise in antisemitism?

As an astrophysicist, it means exploring extraterrestrial real estate before a planetary-scale catastrophe makes Earth uninhabitable. The destination need not be another planet like Mars that Elon Musk terraforms. Instead, it could be a technologically designed habitat in space. Suitable natural habitats are scarce, like prehistoric caves, so we better build our own home on an artificial space platform, akin to a modern Noah’s Ark, and make humanity a multi-platform civilization.

Astronomers define the habitable zone of stars as the distance where liquid water could exist on the surface of a rocky planet, but for a technological civilization — habitability also requires a stable geopolitical system that avoids global nuclear or biological wars and protects its natural resources from toxic industrial products. Most people argue, just like Albert’s family members, that they love Earth and that in the worst-case scenario — they can always leave on the last spaceship. But not me. After years of reading about international politics and noticing that the nature of terrestrial conflicts does not change, I am happy to embark on a one-way trip to interstellar space right now.

Exceeding the escape velocity from the solar system, would carry the benefit of escaping the toxicity of present-day journalism. We can only hope that extraterrestrial journalists are more intelligent than those who suggested that the meteor IM1 detected by sensors aboard U.S. Government satellites could have been a truck. Metaphorically, I already reached the escape velocity from journalistic toxicity thanks to the large community of scientists and the public that support my research, both intellectually and financially. A singing bird cannot be caged by unintelligent critics. The concept of a cage is effective only in the minds of those who do not understand what intellectual freedom means.

But even after boarding an interstellar spacecraft, one may worry that death would remain our biggest threat. Could we be the first generation of people that escapes this biological cage? The futuristic technologist Ray Kurzweil forecasts that humans will reach the longevity escape velocity in 2029. After that, our life expectancy will increase by more than a year for any passing year thanks to artificial intelligence (AI) advancing antiaging medicine. If true, society will have to adjust in many ways. For one, the tenure system in academia will have to be abolished in order to allow all the qualified immortal scholars to contribute.

Another transformation would occur as soon as AI will start to improve AI without human intervention. If AI reaches the escape velocity from human supervision, we might not be aware of how smart it gets. In that regime, AI will take the wheel and humans might stay in the back seat of our racing car of technological advances. This would constitute another reason for recalculating academia.

The sky’s the limit in terms of exceeding the escape velocities from birth environments. Interstellar space is full of such escapees from other stars. Which population of interstellar escapees is most abundant? We can find out by studying interstellar objects. Recently, the Galileo Project at Harvard University announced the publication of the latest paper from the expedition off the coast of Papua New Guinea to retrieve materials from the interstellar meteor IM1. Published in the peer-reviewed journal Astronomy & Astrophysics, this new paper that I wrote with Morgan MacLeod, describes a process by which extraordinary tidal forces “spaghettify” rocky planets into a stream of debris, ejecting rocks above the escape velocity from their planetary systems. This mechanism applies to rocky planets on eccentric orbits around common M-dwarf stars, and explains the unique characteristics of the interstellar meteor IM1, both in terms of its interstellar speed, the inferred abundance of similar rocks, as well as the unique “BeLaU”-type composition of the spherule materials found at the site of the meteor fireball.

If the crust of a spaghettified planet contained technological infrastructure, relics from that infrastructure would be floating in interstellar space. They reached the escape velocity by a natural process involving gravity. But relics of technological life could also exceed the escape velocity from their birth system intentionally, using spacecraft. Even though the chemistry of life-as-we-know-it in liquid water may lead to tens of billions of rocky planets in the habitable zone of their host stars, only a small fraction of the emerging lifeforms would develop rockets that propel them above the escape velocity from the circumstances they were born into.

Just as in Albert’s case, accomplishing escape is a signature of intelligence. Astronomers commonly search for biological-signatures in the form of molecular fingerprints or technological-signatures in the form of radio signals. Exceeding the escape velocity from a birth place intentionally constitutes an intelligence-signature. If the Galileo Project ever discovers a package from a cosmic neighbor, we will know that we are not alone as intelligent beings.

Escape is not always difficult. For example, a jumping frog can escape from the gravitational confinement of any asteroid smaller than a football field. On the other hand, escape is not always possible. For example, a black hole represents the ultimate prison from where nothing can escape, not even light. A singing bird will eventually stop singing once it gets close to the black hole singularity. Just as with Nazi Germany, the feasibility of escape from a black hole is a matter of timing. You better attempt to escape before reaching the event horizon.


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".