On January 8, 2014, a fireball from space burst through Earth’s atmosphere and crashed into the sea, north of Manus Island on the northeast coast of Papua New Guinea. Its location, speed and brightness were recorded by US government sensors and quietly stored in a database of similar events.
That data sat for five years, a source of no dispute until Avi Loeb, a theoretical astrophysicist at Harvard University, and Amir Siraj, then an undergraduate student at the university, stumbled upon it in 2019. Based on its logged speed and direction, Mr. Siraj identified the fireball as an extreme outlier.
Last month, led by Dr. Loeb led an expedition to retrieve fireball fragments in the western Pacific Ocean. On June 21, he claimed that he has. And that, he said to the anger of many of his colleagues, could be evidence of extraterrestrial life.
“Not biological creatures, the way you see them in science fiction movies,” said Dr. Loeb. “It’s probably a technological gadget with artificial intelligence.”
However, many astronomers view the announcement as the latest example of Dr. Loeb made a strange declaration that was too loud and too hasty. His remarks (and a promotional video in Times Square about the search for extraterrestrial life) skew public perception of how science works, they say.
“People are sick of hearing about Avi Loeb’s wild claims,” said Steve Desch, an astrophysicist at Arizona State University. “It’s polluting good science — mixing the good science we do with this ridiculous sensationalism and sucking all the oxygen out of the room.”
Dr. added. Desch that some of his colleagues now refuse to be associated with the work of Dr. Loeb on peer review, the process by which scholars review each other’s research to ensure that only high-quality studies are published. “It’s a real breakdown of the peer review process and the scientific method,” he said. “And it’s very demoralizing and tiring.”
Dr. also started to study. Loeb the fireball catalog from the Center for Near Earth Object Studies at NASA. That led to the object being identified in 2014. From its direction and speed at impact — 28 miles per second — Dr. Loeb and Mr. Siraj that fireball is moving too fast for an object to be gravitationally bound to our sun. That means, like Oumuamua, it must also be interstellar.
They wrote a paper about the discovery in 2019. It was initially rejected by The Astrophysical Journal, but the same journal accepted it for publication in November, a few months after the US Space Command announced in a memo that circulated on Twitter that measurements of the fireball’s velocity are sufficiently accurate to infer an interstellar origin.
Appealing to authority isn’t enough, says Peter Brown, a meteor physicist at Western University in Ontario. It is not known how accurate the US Department of Defense data is, which affects how likely it is that the object came from beyond.
“We know from experience, in operating ground-based radar and optical networks, that you tend to see some percentage of all the events you see that appear to be interstellar,” said Dr. Brown. Today, he continued, almost all of those events can be chalked up to measurement error.
Dr. Brown and others were also disturbed by Dr.’s lack of communication. Loeb to the community of experts who study fast-flying fireballs.
The recent ocean expedition of Dr. Loeb to save the remains of the meteor in question was funded with $1.5 million from Charles Hoskinson, a cryptocurrency entrepreneur, and organized by EYOS Expeditions. The voyage took place about 60 nautical miles north of Manus Island along the expected path of the 2014 fireball. A group of scientists, engineers and sailors and a film crew, as well as Mr. Hoskinson, accompanied Dr. Loeb. He documented the voyage and its results in a 42-part (and counting) series of self-published blog posts.
For two weeks, the science team dragged a custom-built sled equipped with magnets, cameras and lights across the seafloor, picking it up at regular intervals to look for metallic pieces of the 2014 fireball stuck to its surface. In the end, they obtained many sparkling grains, each less than a millimeter in diameter. Preliminary tests carried out on board showed that these spherules were mostly made of iron, with lesser amounts of other metals.
That’s not commonly found in the waters around Manus Island, said Maurice Tivey, a marine geophysicist at the Woods Hole Oceanographic Institution who was not part of the expedition but once used underwater robots to map that region of the seafloor. Instead, sediments and volcanic ash are abundant — material that doesn’t move much once it settles to the bottom of the ocean.
That, combined with the circle of recovered fragments – suggesting they were once aerodynamic – seemed pretty conclusive to Dr. Tivey. “So I think he found pieces of it,” he said.
Skepticism about the effort has flared recently Asteroids, Comets, Meteors Conference that happened while conducting the deep sea expedition. There, Dr. argued. Desch said that if the fireball had moved as fast as reported, nothing would have been found – the meteor would have completely burned up in the atmosphere. Even in the most generous scenario, he said, only one milligram of the material would survive, and it would be spread over tens of square kilometers along the ocean floor.
Dr. also presented Brown at the conference, describing a recent analysis using data from different instruments to check measurements for 17 of the objects listed in the same NASA fireball catalog used by Dr. Loeb and Mr. Siraj. His resultaccepted for publication in The Astrophysical Journal, indicates that the catalog data often get directions and velocities wrong and that the error magnitude for velocity measurements increases for objects with faster velocities.
Those errors were large enough to shift the 2014 fireball from an unbound orbit to a bound one, Dr. Brown — meaning it might not be interstellar after all. He found that if the object was actually traveling closer than 12.5 miles per second to impact, its reported brightness, density and air drag better fit theoretical models of meteors.
On that basis, Dr. Brown said the fireball probably impacted at a lower speed. “If the speed is overestimated, then the object becomes, more or less, within the realm of what we see in terms of other bound objects of the solar system,” he said.
Dr. disagreed. Loeb on that pushback.
“When I was educated as a physicist, I was told when you have a model and it doesn’t agree with the data, it means you have to change your model,” he said, referring to measurements in the NASA catalog.
He also believes, unlike many of his colleagues, that US military sensors can be trusted, even though he does not have access to their raw readings. “They are responsible for national security,” said Dr. Loeb. “I think they know what they’re doing.” That he and his team found what they think are fragments of the 2014 meteor at the location indicated by those measurements only emboldens him.
The government is unlikely to declassify how accurate the data from those devices is. So Dr. Loeb is banking on a different kind of proof: He sent the spherules to labs at Harvard University, the University of California, Berkeley, and the Bruker Corporation in Germany for rigorous analysis and dating. Spherules older than our solar system, or with a unique isotopic signature, must be interstellar.
At Berkeley, Dr. Loeb himself conducted some of the first inspections. Previous tests revealed the presence of uranium and lead, the abundance of which can be used to estimate the age of the material. Two of the spherules found along the expected path of the fireball appear to be as old as the universe itself, said Dr. Loeb.
That’s in contrast to a spherule captured far from the fireball’s path, which Dr. Loeb that may be of geological origin or from another meteorite. He estimated that this spherule is several billion years old, comparable to our solar system.
But even if the fireball really came from another cosmic neighborhood, more evidence is needed to show that the spherules are related to extraterrestrial life.
According to Don Brownlee, an astronomer at the University of Washington who used magnets to collect cosmic marbles from the seafloor in the 1970s, if the spherules don’t contain nickel, they probably aren’t from a natural meteorite. On the other hand, he says, if no oxygen is found, it’s likely that the material passed through Earth’s atmosphere. Dr. Loeb has already written that the first results revealed the absence of nickel, but he did not mention oxygen.
He is open to the possibility that he is wrong, but also likes to use scientific luminaries in response to such concerns. “Einstein was wrong three times,” he said, referring to supermassive black holes, gravitational waves and quantum entanglement – all discoveries that have since been recognized with Nobel Prizes in Physics. “It’s important to test ideas experimentally,” said Dr. Loeb. “Let the evidence be the guide.”
According to Dr. Desch, the meteor community believes interstellar objects exist, and they’re eager for one to hit Earth — there’s no hard evidence yet that it has. “I just want to reassure the public that scientists are not making things up,” he said. “What the public sees in Loeb is not how science works. And they shouldn’t come away thinking that.”
The public can hear more from Dr. Loeb about additional pieces of rock from the bottom of the sea. Later this year, his team intends to return to the waters north of Papua New Guinea to hunt for larger relics of the 2014 fireball. And in 2024, the team said it will visit a site off the coast of Portugal to look for debris from a second meteor Dr. Loeb and Mr. Siraj. asserted is of interstellar origin.
“He could be wrong,” said Rob McCallum, a co-founder of EYOS Expeditions and the main organizer of the recent expedition, adding, “but we won’t know unless we look.”
