The Spatial and Size Distributions of Spherules are Correlated with IM1’s Likely Path

Avi Loeb
6 min readJun 25, 2023


Diary of an Interstellar Voyage, Report 29

(June 26, 2023)

A close-up view under the microscope of a new spherule from Run 16 (June 25, 2023).

Good news. Run 17 went far north away from the likely path of the first recognized interstellar meteor, IM1, and there was only one spherule found of a different composition than the other spherules, despite the long integration time along this line. In comparison, Run 8 went along the likely path of IM1 and recovered 10 spherules out of the 31 found so far. This is supporting evidence that Run 8’s spherules originated from IM1.

Whiteboard count of spherules from the first 17 runs of the magnetic sled.

Run 5 covered the southeast half of Run 8 and the microscope image of the magnetic materials it collected shows an abundance of smaller spherules than in Run 8. This is consistent with the fireball occurring at the southeast corner of both runs. Smaller spherules experience more friction on air because of their larger surface to mass ratio, and so they rain down closer to the explosion site.

Preliminary data on the first 30 spherules, including Run number, date, diameter and color.

Altogether, these clues suggest that the spherules we recovered, primarily along Run 8, originated from the fireball of IM1. The spherules close to the likely path of IM1 show similar compositions in our X-ray Fluorescence analyzer, consistent with the single source origin of IM1.

We cannot tell where the spherules were collected along each run, but we can assign each run a success rate in collecting spherules. By combining the harvests from our 20 runs and the others to come, we plan to generate a likelihood map for the path of IM1.

Start and end times of all runs so far.

This will allow us to calculate the region over which any large relic from IM1 could be retrieved. In our next expedition, we plan to search this region thoroughly with a few-centimeter resolution using a 30 kilohertz sonar. Finding the relic would provide clear evidence for the origin of IM1, be it natural or technological. In the latter case, it would provide insights on the technologies adopted by another civilization. Here’s hoping for a glimpse at what GPT-100 might look like.

But there is a long way to go before we reach that point. So far, the magnetic sled is collecting tiny fragments of IM1.

Sorting of the materials retrieved by the magnetic sled in different runs.

The sample shows some anomalies. There are some shards of corroded iron and large magnetized fragments. We retrieved a huge 3 grams piece that shares the abundance pattern of our spherules close to the IM1 path. If related to IM1, it would dominate the total mass retrieved so far in spherules by a factor of a thousand. We plan to analyze the element and radioactive-isotope compositions of all the materials retrieved with state-of-the-art diagnostics upon our return to the US towards the end of this week.

A scan of a spherule showing localized cavities.

One of the spherules collected away from M1’s path shows an unusually high abundance of 10% by mass for Indium. This rare element which has a similar abundance to silver in the Earth’s crust, is used for many semiconductor applications.

The analysis room humming with activities after midnight. From left: Jeff Wynn, Ryan Weed and J.J. Siler, sorting new material from Run 20. In the background on the top left, Art Wright is efficiently producing new runs around the clock with two days left on Silver Star.

We have two days left for collecting as many spherules as we can and sampling a few runs in control regions away from IM1’s path. I will keep reporting on our findings on this outlet as an opportunity to provide an inside view on how science is done. Today, I was informed by Jesus Diaz that my reports are being translated to Spanish. The translation received more than half a million unique views over the past week and inspired his son to discuss IM1 in a summer camp at the National Natural History Museum in Madrid. Jesus started his email by the words: “Felicidades! I can’t be happier for the success of your mission. Reading your diary has been a source of joy every day.” He went on to say: “Your expedition has reminded me of a poem, “The Diamond of a Star” by the great Spanish writer Federico García Lorca, who was killed by fascists for the mere fact that he thought differently:

The diamond of a star

has cut strips into the deep sky,

The bird of light that wants,

can escape from the universe

It can fly away from the huge nest

where it was a prisoner for ages

without knowing that it is tied to

a chain around the neck.

Extraterrestrial hunters

are hunting the stars,

The solid silver swans

bathing in the water of silence.

In my final class of the spring semester at Harvard University, I asked my students for advice on what to do if we find an extraterrestrial gadget. Would you press a button on it? Half of the students recommended pressing buttons to see what happens and the other half expressed caution from the risks associated with the unknown. At the end, one of the students asked for my take. I replied that I would bring the gadget to a laboratory and examine its content before engaging with it. The default engagement rule for functioning interstellar devices is to treat them with utmost respect as if they were intelligent beings, unless proven otherwise.

In the best-case scenario, we will be filled with awe staring at reflections of our technological future, like a cave dweller staring at a cell phone. Ultimately, our artificial intelligence (AI) systems might imitate those of extraterrestrials and enable a quantum leap in our capabilities. This will be the AI-AI version of Alan Turing’s AI-human imitation game.


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".