Spy satellites confirmed our discovery of the first meteor from beyond the solar system’s news and research
On January 8, 2014, at 17:05:34 UT, an approximately meter-large rock from space swept through the sky off Manus Island, Papua New Guinea, and burned with an energy equivalent to about 110 tons of TNT and debris raining down in the depths of the Pacific Ocean. Fireballs of similar size are not uncommon in the earth’s sky; in fact, a few dozen of them occur every year. But what was unusual about this meteor was the very high speed and unusual direction in which it met our planet, which collectively indicated that it came from interstellar space.
Sensors on a classified US state satellite designed to detect foreign missile launches were the only known witnesses to the fireball. Thanks to a partnership between the Department of Defense and NASA, data describing the incident was eventually shared on a public database maintained by the Center for Near Earth Object Studies (CNEOS) within the space agency’s Jet Propulsion Laboratory, along with data for more than 900 other fireballs recorded by U.S. authorities. sensors between 1988 and today. Data for these events include dates, times, latitudes, longitudes, altitudes, velocities, three-dimensional velocity components, and energies for each. The uncertainties for most of these measurements are particularly omitted from the database – presumably to ensure that the precision thresholds for US global sensing capability are not disclosed, as this information could potentially be exploited by opponents.
My involvement in this meteor goes back to April 2019, when my Harvard academic advisor, astrophysicist Avi Loeb, drew my attention to the CNEOS fireball catalog. At that time, he and I were about eight months into our studies of data related to ‘Oumuamua, the object identified in October 2017 as the first known interstellar visitor to the solar system. Because ‘Oumuamua’s originates outside the solar system, each of its properties, including its own discovery, conveyed previously inaccessible information about our cosmic neighborhood. With the wealth of knowledge carried by interstellar visitors primarily in our minds, Loeb and I had considered the possibility of finding others to study, and CNEOS data seemed promising. Within days, I had identified the 2014 Manus Island fireball as a potential interstellar meteor candidate. Loeb then suggested that I use the impact rate in combination with knowledge of the kinematics of small body populations in the solar system to estimate the probability that it originated elsewhere, beyond our solar system. With this approach in mind, I then proposed a more precise method of deriving the object’s orbit that accounted for the gravitational pull of our sun and its planets. Loeb agreed to my suggestion and I got started quickly.
At the Earth’s distance from the sun, all objects that move faster than about 42 kilometers per second are in an unlimited, hyperbolic orbit relative to our star, which means that it is too fast to be caught by the sun’s gravity. Everything that travels across this local celestial velocity limit can then come from (and if it returns to) interstellar space without hindrance. The CNEOS record for the 2014 Manus Island fireball indicated that the meteor hit the Earth’s atmosphere at about 45 kilometers per second – very promising. However, part of this velocity came from the object’s motion relative to the earth and the earth’s motion around the sun. By teasing these effects using computer programs that I wrote, I found that the object had passed the earth from behind before it hit our atmosphere and probably had a solar-relative speed closer to 60 kilometers per second. The corresponding orbit that I calculated was clearly unbound from the sun – even though there had been major uncertainty errors. If the data were correct, this event would be the first interstellar meteor ever discovered. And it was clearly hiding.
Extraordinary claims, of course, require extraordinary evidence. So Loeb and I made reverse estimates of the measurement errors of the classified satellites, using independently verified data on other fireballs in the CNEOS database and elsewhere in the scientific literature. After this arduous check of reality, we were left with the same astonishing conclusion: the fireball of 2014 apparently originated from interstellar space. In short, we wrote a draft that reported our discovery for peer-reviewed publication.
Magazine judges rejected the unknown nature of the piles of errors, so we enlisted the help of Alan Hurd and Matt Heavner, scientists at the Los Alamos National Laboratory with high-level safety permits and an interest in promoting collaboration with the public sector to enable blue sky science. In short, Heavner contacted the anonymous analyst who had derived the meteor’s velocity components from the classified satellite observations, and confirmed that the relevant uncertainties for each value were not higher than 10 percent. Included in our error analysis, this indicated an interstellar origin with 99.999 percent certainty, but the paper was again rejected by judges, who objected to the fact that the statement of uncertainties was a private communication with an anonymous US government employee, and not an official statement from the US government , which Heavner had a hard time getting. After several more unsuccessful attempts to penetrate the veil of secrecy to the satisfaction of magazine reviewers, we unfortunately went on to other research, leaving the true nature of the 2014 meteor unconfirmed.
A year later, however, we were approached by Pete Worden, chairman of the Breakthrough Prize Foundation, with an introduction to Matt Daniels, who at the time was working for the Secretary of Defense’s office. Daniels had read our repression about the 2014 meteor and wanted to help confirm its origins from within the US government. After a year of laboriously navigating several layers of state bureaucracy, Daniels was able to procure in March / April 2022 official confirmation from Lieutenant General John Shaw, Deputy Commander of the US Space Force, and Joel Mozer, Chief Researcher of the branch’s Space Operations Command, on relevant uncertainties – and thus an effective confirmation that the meteor was of true interstellar origin.
Three years after our original discovery, the first object to emerge outside the solar system observed to hit Earth – the first known interstellar meteor – has been officially recognized. The meteor from 2014 is also the first recorded interstellar object discovered in the solar system, which preceded ‘Oumuamua by more than three years, and is one of three interstellar objects confirmed so far, along with’ Oumuamua and the interstellar comet Borisov.
The interstellar nature of the 2014 object has fascinating consequences. Its size suggests that each star needs to contribute a significant amount of similar objects during its lifetime to make the 2014 discovery likely – suggesting that there are many more interstellar meteors to be found. And its high velocity relative to the average velocity of our neighboring stars suggests that it could have been ejected from the depths of another planetary system, relatively close to its star. This is surprising, since one can naively expect that most interstellar objects instead come from far more distant circumferential regions where the escape velocities are lower, namely the clouds of comets found on the edge of many star systems.
This new field, the study of interstellar meteors, really has a lot to tell us about our place in the cosmos. Further studies of the observed properties of the meteor from 2014 may reveal new insights into our local interstellar environment, especially compared to the properties of its successors, ‘Oumuamua and Borisov. Meteor databases are ripe for searches, and there are new motives for building new sensing networks, with a focus on discovering future interstellar meteors. Observing an interstellar meteor burning up in real time would make it possible to study its composition, which would provide new insights into the chemistry of other planetary systems.
The holy grail of interstellar object studies would be to obtain a physical sample of an object that originates outside the solar system – a goal as bold as it is scientifically groundbreaking. We are currently investigating whether a mission to the bottom of the Pacific Ocean off the coast of Manus Island, in the hope of finding fragments of the 2014 meteor, may be fruitful or even possible. Any sufficiently large interstellar meteor detected in the future should also produce a burst of debris, which we could potentially track down and analyze. There is, of course, another approach to getting samples, which I, as head of interstellar object studies for the Galileo project, am happy to continue as well: a meeting with spaceships. In collaboration with Alan Stern, the principal investigator for NASA’s New Horizons mission, we have now received funding to develop a concept for a space mission for some future interstellar object.
Like exotic shells, these messengers from the stars have washed ashore on our planetary shore for billions of years, each carrying secrets of its – and our – cosmic origin. Now we are finally starting to comb the shoreline.