Hunting for More IM1 Spherules

Avi Loeb
4 min readJun 21, 2023


Diary of an Interstellar Voyage, Report 21 (June 22, 2023)

Our metallic pearls in a haystack of geological and biological debris on the ocean floor. Spherules showing up on the microscope image of magnetic particles from Run 8 along the most likely path of the first recognized interstellar meteor, IM1.

The count of spherules from IM1’s site keeps growing. We now have 9 of them and they seem to have consistent compositions. In the next seven days we will be hunting for as many magnetic spherules as possible using the sled. Many fans congratulated me for the success of our research team and concluded their message with the greeting: “Happy sledding!”

My wife loved the image of the spherules and asked if I could put one of them on a necklace that she would wear. I explained that their size is a third of a millimeter, roughly the size of the head of a pin, which makes them too small to thread. Obviously, we will be searching for bigger spherules. These have a smaller surface area per unit mass and encounter less friction with air. As a result, they should be distributed farther along the meteor path towards the ocean surface. Once we pinpoint the IM1-ocean impact point, we will search for any large object that may represent IM1's core. If IM1 were a spacecraft from another civilization, finding it could be transformative for the future of humanity.

The sled has a mass of 200 kilograms and it went to the bottom of the ocean at a depth of 2 kilometers to find particles that are a third of a millimeter in size and a few tenths of a milli-gram in mass. That we were successful on such a vast range of scales is testimony to the quality of our team members. If I imagine missing any of the team members from the effort, the mission would not have been successful.

The Galileo Project’s Interstellar Expedition team on the front deck of the ship, Silver Star, upon departure from Lorengau, Manus Island, Papua New Guinea (June 14, 2023).

Therefore, this morning I sent the following memo to all team members:

“Dear Interstellar Expedition team,

After a thorough consultation with Jeff Wynn, we decided to follow the following protocol for the publications coming out of the findings from the Interstellar Expedition:

1. Our discovery papers will include all members who contributed to the success of the mission. The author list will refer to “Interstellar Expedition team” and include all team members in alphabetical order. In addition to the recipients of this email, we will include support people who were on Silver Star and were crucial for the success of the project (and whose email addresses I will get from Rob McCallum).

2. Our first set of papers will be submitted to a prestigious and highly regarded journal in the related scientific community.

3. Jeff Wynn will collate all the input content and data from team members and I will assemble it into coherent papers. Feel free to send Jeff anytime input material that you want to be mentioned in our team papers.

This is a team effort. Let us work together as we convey the data and related analysis to the broader scientific community through peer-reviewed publications.

It is a great pleasure to be working with all of you. If progress continues to be made as expected, we will open the champagne bottle soon.


Abraham (Avi) Loeb
Frank B. Baird Jr. Professor of Science

Head of the Galileo Project

Director, Institute for Theory & Computation
Harvard University

It is truly remarkable to witness a team of professionals, some from outside academia, coming together in this heroic effort. Once we collate a large enough mass of spherules and figure out their precise composition, we will celebrate. Cheers!


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".