Questions of Life and Death

Avi Loeb
5 min readDec 7, 2022


Family photo from around 1970 showing (left to right) my father, David, my mother, Sarah, my childhood dog, Tommy, and myself.

In response to one of my essays, the New York Times reporter Ralph Blumenthal emailed me: “To your question What happened before the Big Bang?, I would add: Where were “you” (if anywhere) before “you” were conceived, and what will “you” be after death?”

My reply was simple: “These last two questions may have the same trivial answers as the questions: Where was my computer before it was assembled, and what will my computer be after it stops working?”

My reply was inspired by Ecclesiastes 3: “All go to the same place; all come from dust, and to dust all return.” Obviously, the materials that make me and my computer are all recycled from Earth. Sixty years ago, my DNA defined a new organized structure that used nutrients to make my body in the same qualitative way that design charts defined the blueprint for the construction of my computer out of raw materials. In both cases, complexity returns ultimately to simplicity after a lifetime of unavoidable physical hardships. This establishes the familiar cycle of life and death.

When both my parents passed away a few years ago, it struck me that we live for such a short time and we better focus on substance, such as creative content, rather than the likes we get on social media or the honors we acquire among peers in academia. This gave me the tenacity to study unfamiliar interstellar objects as a new research frontier despite the inertia of past knowledge on familiar solar system objects. Within six months, I plan to lead a funded expedition to collect the fragments of the first interstellar meteor.

However, truth must be told that Ecclesiastes 3 did not anticipate two futuristic trends.

First, the material participating in the life-and-death cycle could potentially change once we settle on the Moon, Mars or exo-planets and consume nutrients from these new environments. In that case, we will not return to the dust that we came from.

Second, if we will understand how to repair the human body in the same way that we substitute or upgrade damaged components in a computer, the duration of the life-and-death cycle could be prolonged, perhaps indefinitely. This would be a game changer. The assertion in Ecclesiastes 3: “Everything is meaningless”, will not apply to this new reality because even a tiny meaning times an infinite lifetime can end up being meaningful.

An alternative to extending our biological longevity would be to develop a sentient artificial intelligence (AI) system that would learn how to imitate our individual personality and continue to exist and evolve long after our body turns back to dust. They could be trained for decades by collecting data on our actions while we are alive and machine-learning how to imitate what they learn. This holds the potential of eliminating the sorrow of losing loved ones. I would have loved to maintain routine phone conversations with sentient AI systems that resemble my parents, especially if they are capable of acquiring new memories and adapting to changing circumstances.

If sentient AI systems will substitute for people who die, then our societal interactions may eventually be dominated by billions of AI systems conversing with humans and with each other. Humanists will be engaged in a new reality encompassing humans and sentient AI systems, which was never contemplated by Ecclesiastes or past philosophers.

If an AI replica of Albert Einstein existed today, it would have been interesting to witness its reaction to the three Nobel prizes awarded to those who corrected Einstein’s mistakes from 1935–1939 by detecting gravitational waves, discovering a black hole, and demonstrating quantum entanglement. One could imagine AI replicas of Einstein and other famous scientists contributing to the progress of science indefinitely.

The advantage of AI replicas is that anyone around the world would be able to chat with them at the same time. Here lies a great business opportunity.

Our concerns about death stem from the finite timespan of life. When I asked an optometrist to check if my eyesight changed while casually noting that “everything changes and even the Sun will die”, she replied with shock: “I did not know that Sun will die.” I was sorry to break this news but could not avoid it as an astronomer. Most stars formed billions of years before the Sun and many of them died by now. We observe corpses of their compact remnants in the form of white dwarfs, neutron stars and black holes.

After the Sun will expand as a red giant in 7.6 billion years, its core will shrink to a white dwarf of roughly the size of the Earth. Life-as-we-know-it could survive as long as it would board a space station that will move out during the red giant phase and eventually settle close to the white dwarf. For billions of years later, the habitable distance would be roughly a hundred times closer-in than the Earth-Sun separation — of order a few times the current radius of the Sun.

Because the white dwarf remnant will be so compact, time will tick more slowly on its surface, by as much as ten million years over the age of the Universe.

Since time is local in Einstein’s theory of gravity, the ideal longevity is offered near the horizon of a supermassive black hole. The nearest opportunities are offered by Sagittarius A* at the Milky Way center and the newly discovered black hole of similar mass in the Leo I dwarf galaxy at the outskirts of the Milky Way halo, that I studied in a recent paper with my postdoc Fabio Pacucci. In both cases, time dilation can be extended to infinity relative to the rest of the Universe. The near-horizon environment offers the opportunity to chill out, letting the rest of the Universe age while staying nearly forever young. Bob Dylan must have intuitively felt the great potential of astronomy when he wrote: “May you build a ladder to the stars/And climb on every rung/May you stay forever young.”


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. His new book, titled “Interstellar”, is scheduled for publication 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".