Meteors, Spherules, and Aliens

Did Harvard astronomer Avi Loeb discover the remnants of an interstellar meteor in the form of spherules on the ocean floor? Could they be of alien origin?

In today’s special edition of the Michael Shermer Show the guest, Harvard astrophysicist Dr. Avi Loeb, announces that he has discovered material remnants from an interstellar object that collided with Earth and ended up on the bottom of the Pacific Ocean near Papua New Guinea, in an expedition he led over the summer. The object, which he labels IM1—Interstellar Meteor 1—collided with Earth nearly a decade ago and was tracked by US government satellites, which gave Loeb and his team coordinates for where to look (more on this below).

Most of the meteor burned up in the atmosphere but tiny spherules remained on the ocean bottom, which Loeb retrieved and had analyzed in labs at Harvard, UC Berkeley, and the Broker Corporation.

Caption: Avi Loeb and his team with the magnetic sled they drug across the ocean floor to retrieve spherules.

These spherules are tiny—smaller than a grain of sand—and there are literally trillions of them around the world of both terrestrial and extraterrestrial origin, so whether or not these particular spherules are Interstellar in origin remains to be seen, despite Loeb’s confidence that they are.

Caption: Collected material from the magnetic sled at IM1’s site, showing a 0.4-millimeter diameter iron-rich spherule (white arrow) amongst a background of shell hash and other debris.

Here is what Loeb announced today in a press release:

The Interstellar Expedition of June 2023–led by the expedition’s Chief Scientist, Harvard University Astrophysicist Avi Loeb and coordinated by Expedition Leader Rob McCallum of EYOS Expeditions retrieved hundreds of metallic spheres thought to be unmatched to any existing alloys in our solar system from the seafloor in the Pacific Ocean near Papua New Guinea. Early analysis shows that some spherules from the meteor path contain extremely high abundances of Beryllium, Lanthanum and Uranium, labeled as a never-seen-before “BeLaU” composition. These spherules also exhibit iron isotope ratios unlike those found on Earth, the Moon and Mars, altogether implying an interstellar origin. The loss of volatile elements is consistent with IM1’s airburst in the Earth’s atmosphere. “The “BeLaU” composition is tantalizingly different by factors of hundreds from solar system materials, with beryllium production through spallation of heavier nuclei by cosmic-rays flagging interstellar travel,” says Avi Loeb. 

Caption: Electron microprobe image of S21 from Run 14 in the high yield region of IM1’s path.

The press release of August 29, 2023 was timed with the publication date of Dr. Loeb’s new book, Interstellar, whose subtitle hints at the scientist’s larger ambitions: The Search for Extraterrestrial Life and Our Future in the Stars. I read the entire book and enjoyed it thoroughly, the details of which we discuss in our conversation.

Dr. Loeb’s co-authored paper, posted online here, has not been peer reviewed. In fact, none of the world’s leading experts on spherules have even seen any of Dr. Loeb’s evidence. So in preparation for this episode, I contacted Peter Brown, an astronomer at Western University, Ontario, who specializes in the physics of meteors, and in addition to outlining the relevant technical and scientific issues involved in such a discovery, he directed me to the five leading experts in the world on spherules. These include:

George Flynn, SUNY, Plattsburgh

Don Brownlee, University of Washington

John Bradley, University of Hawaii

Michael Zolensky, NASA

Matthew Genge, Imperial College, London.

Steven Desch, Arizona State University

All expressed their skepticism about Dr. Loeb’s findings, which I read on air to Avi to get his response (see the show notes below). Listen to the experts and Dr. Loeb’s response to their skepticism in this episode, and read on below.

(Note: Steven Desch’s initial statement, included below, was so negative that I chose not to read it on air; I include it here for full disclosure of what he thinks about this research. I also included Dr. Desch’s additional comments on why many scientists are skeptical of the US government data on the meteor’s trajectory and impact site.)

I should add that I am a member of the Galileo Project team, which organized this expedition, and I consider Avi a friend and colleague who always welcomes my skepticism in our weekly team meetings. To that end let me emphasize that he is not claiming to have discovered alien technology, only the remnants of an interstellar object. Unfortunately, the media coverage surrounding the Galileo Project in general, and this expedition in particular, is only interested in whether or not we have made contact with ET. We have not, and Avi is not claiming that we have. But here is an example, which I tweeted out recently, of what Avi is claiming and what the media reports:

My own view is that aliens are very likely out there somewhere—given the astronomical numbers of hundreds of billions of galaxies, each of which has hundreds of billions of stars, each of which has multiple planets it seems highly unlikely that we’re alone in the cosmos—but that they have very likely not come here in any shape or form: nonhuman biologics or extraterrestrial metalogics (my own neologism echoing government whistleblower David Grusch’s ridiculous description in his Congressional testimony of alien pilots as “nonhuman biologics”). The universe is vast and consists of mostly empty space. The odds are very long indeed that any extraterrestrial spacecraft could encounter our planet, much less leave traces for us to evaluate.

But in keeping with Cromwell’s Rule in Bayesian reasoning (never assign a 0 or 1 probability to anything because, as Oliver Cromwell famously said, “I beseech you in the bowels of Christ you might be mistaken”), we should maintain an open mind, be willing to adjust our priors and update our credences, and keep searching. That is why I support the SETI program and am on the Galileo Project team. The odds may be long, but the payoff would be spectacular if we ever did discover extraterrestrial intelligence or the technological artifacts of an extraterrestrial civilization.

Show notes:

Here are the responses I received via email from these scientists expert on meteors and spherules:

Michael Zolensky, NASA:

Yes, I know all about this, but I would rather withhold any question or statement until I see what he actually has. I’m sure you understand.

John Bradley, University of Hawaii:

Dismay does not begin to describe my sentiments about Loeb's scientific shenanigans. To assert that cosmic spherules (i.e., melted micrometeorites) that litter the seafloor are parts of an alien spacecraft defies common sense, unless of course alien spacecraft are actually made of rocks. This sort of nonsense may explain why so many in the public at large harbor an abiding antipathy towards science. Academic freedom, like (past) Presidential powers, is not without its limits.

Matthew Genge, Imperial College, London:

Sure...I'd be interested to see the paper too. I am guessing it won't be in Science or Nature. However, I do think pushing the envelope is necessary as a scientist, as is being provocative, but at the end of the day, the more dramatic the conclusion, the stronger the evidence has to be. However, I haven't seen the data, thus I can't give a proper opinion, only an impression on what has been reported in the media. My question to Avi Loeb would be this:

"The only evidence universally accepted by scientists for an origin beyond our solar system is an isotopic compositions significantly outside the range of materials within our solar system. What isotopes have you analyzed in the materials you have recovered? What is their range as a ratio to maximum solar system values?" 

I suspect his answer will be to dismiss the requirement and instead to point to dynamic evidence (e.g. entry velocity from meteor observations). If he tries to claim this add:

"Considering radar observations are highly uncertain how can you be certain that this meteor was interstellar? Many meteor scientists claim there still has never been an unequivocal interstellar meteor."

It might, however, be easier to put me on the same podcast with him so we can talk. I even agree with him on some things...for example, the compositions I've seen reported seem to be artificial, I agree they are not interplanetary dust from our solar system, however, I would suggest they are much more likely to be terrestrial and anthropogenic. I also have some suggestions by which he might be able to distinguish between terrestrial and extraterrestrial materials. Finally:

"If you heat Ti-rich metal in an oxygen-rich atmosphere, it reacts to form titanium oxides. It is difficult to say, since the results havent yet been published, but if your particles are made of titanium-rich metal, then they haven't experienced atmospheric entry."

I do, however, agree with Avi. If an alien civilization has ever visited Earth, now or in the distant past, they may have left tiny pieces of evidence on our planet in the form of droplets formed by their atmospheric entry. The evidence, however, must be exceedingly strong. For example, several years ago we found iron-manganese oxide spherules in 100-million year old sea floor rocks, and it crossed our minds that these materials are used in spacecraft alloys, however, it turned out that ordinary interplanetary dust is transformed during its time on the seafloor by replacement of nickel by manganese. Geology is a complicated business since we still don’t know all the processes that operate in the natural environment. 

George Flynn, SUNY, Plattsburgh:

Cosmic spherules have been recovered from the ocean floor since the Challenger Expedition in the 19th century. Since the Challenger Expedition recovered these spherules they have also been recovered from lakes, and even the Polar Ices. A good summary of the history is given in this paper. So I guess the most important question is how do the spherules Loeb recovered differ from the ones routinely collected and identified over the past century and a half, and what specific characteristic(s) distinguish them from the spherules of likely Solar System origin that have been studied in detail over that time.

I think the important point is that extraterrestrial metallic spheres have been collected from the seafloor in numerous locations in the Pacific Ocean (and other places around the world) since the 1880s. Finding these spherules in a location where Loeb expects ablation debris from a specific object does not demonstrate they are from that object. He should expect to find these spheres pretty much everywhere. So, to claim they are interstellar he must demonstrate that there is some specific feature that indicates they are not ablation products from Solar System meteors that enter the atmosphere all the time.

Don Brownlee, University of Washington:

If something is found from outside the solar system, it will have a different isotopic composition than Earthly materials. This property has been used to identify thousands of small presolar grains in meteorites and interplanetary dust. These grains are usually a micron or smaller and they formed around other stars but were preserved inside the asteroids that generate meteorites. With the right equipment, these rare grains can be proven to have formed around other stars. It should be simple to ID interstellar material and it is done routinely for the rare presolar grains.  As Carl Sagan famously said, “extraordinary claims require extraordinary proof.”  Isotopic composition or age older than the Sun would be proof.

My thoughts are that most interstellar solids entering the solar system in sizes of microns to kilometers were probably made during the peak of star formation in the Galaxy and are over 10 billion years old. These objects have typically spent billions of years in interstellar space at near zero temperature—no heat for Capt. Kirk or semiconductors. The first interstellar solids entering the solar system on unbound orbits were found by dust detectors on the Ulysses and Galileo spacecraft.   

If an object is ET made, it surely will not be made of transparent aluminum or any other fantasy material.  It would be made of materials that could be used to make spacecraft. The materials that we use to make spacecraft are exotic materials that never would be expect to be found in natural planetary materials. Such exotics are metallic Al, metallic Ti, carbon fiber, kapton sheet with metal coating, gold connectors, high strength steel, teflon, copper wire, epoxy and a vast array of engineered materials  that would never have existed without human or ET production. 

Steven Desch, Arizona State:

Note from Shermer: This is the statement that I opted not to read on air:

"Dr. Loeb, your record in some astrophysical fields does not make you an automatic expert in planetary science. Yet you ignore the literature created by hundreds of experts, and you misquote the few papers you cite. You do not correct your mistakes. You are dismissive of peer review. You make it harder for scientists to do their jobs: your sample collection techniques mean we can't do paleomagnetic studies on these spherules, and your ham-handedness has made it harder to obtain permits from Papua New Guinea to collect more. Worse, at a time when the public needs to understand science more than ever, you have corroded public trust and understanding in science. You loudly advertise unsubstantiated and debunked claims, then whine when challenged. The hallmark of science is self-correction, for scientists to be skeptical of each other, so the public can trust in the results. Your work in planetary science has not withstood even mild scrutiny, but instead of taking the time to learn, you claim other scientists are close-minded and mediocre. That's not visionary. It's intellectually lazy and misrepresents to the public how science works." 

I wish it didn't come to this, but I feel that the great scientific work of my peers should not be dismissed—and more than that, the whole scientific process needs to be defended. I have sparred with Loeb on matters from 'Oumuamua, to the Chicxulub impactor, and now to the 2014-01-08 bolide. Regarding the interstellar meteor, I have engaged in my own research, much of which I presented at the June 2023 Asteroids, Comets & Meteors conference in Flagstaff. Peter Brown of University of Western Ontario also presented his research as well. Below I summarize the science case as it stands now. 

Everyone agrees that if the meteor entered at the speed (45 km/s) and vector reported in the CNEOS database, it would be interstellar; but no scientist trusts those numbers, and it's VERY likely this meteor came from our solar system.

—Previous attempts to verify the CNEOS database numbers (using those also observed from the ground) shows they are wildly in error in about 1/3 of cases; sometimes the reported vectors are 90 degrees off. (Devilleux et al. )

 —Peter Brown demonstrated that the uncertainties in speeds for high-speed meteors are especially large; for this one they're probably ±20 km/s.  The 2014-01-08 bolide probably came in at 25 km/s (which would be more consistent with other aspects of its light curve), and therefore wasn't interstellar. (Brown et al. 2023 )

—I'm working with Maria Hajdukova in Slovakia, who is an expert on meteors, and in work in preparation, they show that all the fast meteors in the CNEOS database have one velocity component that's really funky (i.e., 45 km/s is probably measurement error). 

There's nothing obviously unnatural about this bolide.

Assuming anyway the 2014-01-08 bolide was moving at 45 km/s, Siraj & Loeb (2022, ApJ) have implied it couldn't have been a natural material because it broke up at a ram pressure of 200-250 MPa, whereas they cite a paper and claim iron meteorites can't withstand pressures greater than 50 MPa. In fact they completely misquoted the papers they cite, which show iron meteorites can withstand pressures up to 700 MPa.

If the meteor did come in at 45 km/s, nothing would have survived. 

—In a preprint on arXiv, Tillinghast-Raby (a poor student), Loeb & Siraj claim that 10% of the meteor would have survived entry, but they falsely assumed the bolide exploded with every piece moving outward at 41 km/s (so that backward-moving material sees its forward motion almost completley cancelled).  Actually, meteors disintegrate and all that material keeps moving forward at 45 km/s.

—The formulas for how much material survives are in the meteor literature and are pretty well established once you define the 'ablation parameter'. For any non-exotic material, < 0.0001% of this meteor would have survived if it were moving at 45 km/s. We're talking milligrams.

There is no way to pin down the location of the material to better than tens of square kilometers. 

—In a preprint on arXiv, Siraj & Loeb tried to pin down the location using seismometry, but this preprint has many mathematical errors (a figure even shows the bolide moving east to west, instead of west to east!), and tries to attribute a signal to the bolide that is probably the signal of a passing truck or something on the island. It's a hot mess. The uncertainty in where it fell is > 10 km.

—In my ACM talk, we showed that in the minutes it takes spherules to sink to the ocean floor, the currents there would have distributed spherules across many kilometers east-to-west. 

At no point did Loeb seem to recognize that the ocean floor is littered with metallic spherules from a variety of sources.

—Micrometeorites have been purposefully collected from the seafloor using magnets for at least 50 years (ask Don Brownlee, PI of the Stardust mission), and were recognized for almost a century before that. Loeb cited NONE of this literature. As my oceanography colleague Hilairy Hartnett puts it, there are "squillions" of such spherules almost anywhere you can put a magnet on the seafloor. 

—Metallic spherules come from micrometeorites, but also from volcanic activity, and human industrial processes. Loeb presented no plan ahead of time for how he would distinguish these. 

—I'm not an expert on what variety of materials can be found on the seafloor, but I understand there are many industrial byproducts, and all of these would have to be ruled out to make any claims at all. 

Michael Shermer is the Publisher of Skeptic magazine, Executive Director of the Skeptics Society, and the host of The Michael Shermer Show. His many books include Why People Believe Weird Things, The Science of Good and Evil, The Believing Brain, The Moral Arc, and Heavens on Earth. His new book is Conspiracy: Why the Rational Believe the Irrational.