We Have 25 Spherules from IM1’s Site!

Avi Loeb
5 min readJun 24, 2023


Diary of an Interstellar Voyage, Report 27

(June 25, 2023)

Our 25 babies in their delivery room. The spherules are placed in vials and will be analyzed in the coming weeks with results published in peer-reviewed journals.

By now, we have 25 spherules from the site of the first recognized interstellar meteor, IM1. They are kept in vials and organized in a plastic container, like babies in their beds within a delivery room.

We nearly doubled the threshold for opening the champagne bottles on Silver Star. I asked Rob McCallum why he brought the bottles on board in the first place and he replied that he is an optimist. Life is sometimes a self-fulfilling prophecy, so it is better to be an optimist.

Last evening was stormy and so we postponed the celebration to tonight. At its core, this will be a celebration of the scientific method and of courage to follow it despite all odds. Fishing for milligram-mass babies after they settled to an ocean floor depth of 2 kilometers nearly a decade ago using a 200-kilogram magnetic sled is no small feat.

The count of spherules is at 25 and we have three days left with up to 9 additional runs.

What counts for our future analysis is the total mass in spherules. This can be estimated by summing up the spherule volumes which scale as the cube of their individual sizes. Altogether, we have about 30 milligrams of spherule material as of now.

Based on the energy radiated from IM1’s fireball and the measured IM1’s speed, one can infer the mass of material entrained in the fireball to be about 500 kilograms. If we end up retrieving 50 milligrams over the remaining 3 days of the expedition, the total mass we collect would constitute one part in ten million of the fireball’s debris mass.

Extracting magnetic matter from Run 15 at 1AM on June 25, 2023.

To summarize: a team of two dozen researchers and support staff spent two weeks and 1.5 million dollars on bringing a tenth of a millionth of the debris mass from IM1 to the deck of the ship Silver Star. To paraphrase Frank Sinatra’s song `New York, New York’:

“If I can make it there, I’ll make it anywhere

It’s up to you, Silver Star, Silver Star”

For the history books, we now possess materials out of a package delivered to our doorstep from interstellar space. The distance it travelled is trillions of times farther than the range of Amazon delivery services. We plan to analyze this material thoroughly in the coming weeks and publish the results in peer-reviewed journals.

Retrieval of materials from Run 15 of the magnetic sled.

The success of the Interstellar Expedition constitutes the first opportunity for astronomers to learn about interstellar space by using a microscope rather than a telescope. It opens the door for a new branch of observational astronomy.

From a broader perspective, dedicating our full attention to a speck of mass is not unusual. We need only remember that the total mass in the bodies of the entire human population on Earth is less than a trillionth of the mass of Earth. Yet, we focus most of our daily attention to the whereabouts of this mass.

But there is more to this detective story. If further analysis of the 50 milligrams retrieved from IM1’s site will inform us that IM1’s composition requires a technological origin, we will know that we are not alone. The feeling would be similar to tracing the contact information of a lost family member. Such information may be stored on a tiny piece of paper but its power is transformative.

It is possible that meteor explorers saw material from interstellar space before us but were not able to figure out its interstellar origin because they did not know that the parent meteor was not bound by gravity to the Sun. IM1 is the first object for which we have that information, as confirmed by the US Space Command at the 99.999% confidence.

In our next expedition we plan to use a 30-kilohertz sonar system to map the ocean floor around IM1’s path in search for any large remnant. If we recover it, we would immediately be able to tell whether it is natural or technological in origin. In the former case, we would learn about the formation sites as well as ejection processes of interstellar rocks. In the latter case, we would learn about a smarter kid in our cosmic neighborhood that managed to send a package to our doorstep while we are engaged in in-house quarrels and rarely leave our home planet.

Here’s hoping for many more expeditions to retrieve interstellar meteors in the future. Perhaps they will inspire us to reciprocate by sending our own probes to the doorsteps of their senders.

Unlike Elon Musk who dreams about dying on Mars, I dream about burning up as a meteor in the dark sky of a habitable exoplanet. I will be particularly honored if a curious scientist out there will be imaginative enough to collect milligrams of my ash and examine them under a microscope.


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".