Opening Interstellar Packages in Our Mailbox

Avi Loeb
4 min readAug 12


Life feels sometimes like an involuntary swim in turbulent waters. As I opened my mouth wide for my dental examination yesterday, the dental assistant — whom I had never met before — asked: “I follow your research with great interest. Can you tell me the composition of the spherules you retrieved from the Pacific Ocean?” I politely declined and promised to give her all the details in my next dental appointment, after the expedition’s scientific paper will be publicly available.

Upon my return home, I joined a podcaster who challenged me with another difficult question: “What do you imagine or wish aliens to be like?” I replied that as a scientist guided by evidence, I prefer not to imagine and remain agnostic until the evidence shows up. When we pay for a science-fiction movie, we have expectations. But since Nature shows up in our sky for free, we should enjoy the show without expectations. In reply to the second part of the question, I wish extraterrestrials to serve as role models for us earthlings, as powerful as God is in our religions and wiser than our best thinkers. As discussed in my new book Interstellar, we desperately need a better role model than our politicians and entertainers.

Given our advanced cameras, telescopes, and expedition-microscopes, we cannot ignore the scientific opportunity to search for packages sent by our cosmic neighbors, because the implications that a successful search carries for the future of humanity are huge. This resembles the wager of the philosopher Blaise Pascal about God. Indeed, a more advanced technological civilization could appear to us like an approximation to God.

A recent poll indicates that nearly two thirds of Americans believe that intelligent life exists on other planets. Another poll found that whereas nine in ten Americans believe in a higher power, only a slim majority believe in the biblical God. Could these belief systems be intertwined? The good news is that we can do better in figuring out the reality that we live in.

The great benefit of scientific instruments is that they are capable of testing beliefs experimentally by placing opinions under the guillotine of fact-checking. The question whether interstellar objects contain space trash from extraterrestrial civilizations should not be a matter of debate on social media or clickbait media distortions, but a result of exquisite data from mass spectrometers that study the sample of spherules retrieved from the first recognized interstellar meteor, IM1.

A typical interstellar journey spans thousands of light years and could take a billion years for Voyager-like spacecraft across our Milky Way galaxy. Given these scales, most technological probes might stop operating and accumulate in interstellar space like plastic debris in the ocean.

At the same time, functional devices would not be waiting for guidance from their senders but instead use artificial intelligence to pursue their goals autonomously. In this context, the excessive control exhibited by engineers in NASA’s Jet Propulsion Laboratory over the Perseverance Rover and the Ingenuity helicopter on Mars, appears like helicopter parenting, literally speaking.

We have a lot to learn from Mother Nature. A dandelion flower is not connected with an umbilical cord to its seeds, nor does it send real-time instructions to the seeds about what to do after they get carried away by the wind. Similarly, any technological devices that remain functioning after traveling through interstellar space would pursue the mission they were programmed to accomplish without reporting back or waiting for guidance from their senders.

The civil duty of scientists is to apply the scientific method to questions that resonate with the majority of society, such as: “Do we have neighbors in our galaxy?” That this proposition is not self-evident in academic circles today, implies that common sense is not common.

My podcast ended with the question: “If you could ask extraterrestrials one question, what would it be?” The top question on my mind is: “What happened before the Big Bang?” because this question encapsulates the biggest mystery of physics over the past century: how to unify quantum mechanics and gravity? It also touches upon the beginning of our cosmic roots and the origin story in many religions and philosophical narratives. The next questions on my list is who else is or was in our cosmic neighborhood, and how can we join the nearest party?

Asking such questions would only be possible in an encounter with a functioning entity. Judging by our own space products, it would be more likely to encounter non-functional objects from a distant source in the Milky-Way. Those would collide with Earth and burn up as interstellar meteors in our sky. In my next dental appointment, I will clarify to the assistant that the content of most interstellar packages in our mailbox may have expired long ago.


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".