Harvard astrophysicist Avi Loeb says he has found good evidence for alien technology in the solar system, what could be called alien garbage, and that some other scientists don’t take his ideas seriously because of “groupthink.”
In his new book”Extraterrestrial: The First Sign of Intelligent Life Beyond Earth” (Houghton Mifflin Harcourt), set to be published Jan. 26, Loeb describes his journey to a radical position on the strange interstellar visitor that’s been dubbed’Oumuamua — a cigar- or disc-shaped object that whizzed through our solar system inside 2017.
When ‘Oumuamua flashed through the sun’s neighborhood in 2017, scientists didn’t get a very good look at it, as it moved through so quickly. But even with those disadvantages, observers noted several anomalies. Loeb published a paper in 2018 arguing that the data showed an object unlikely to exist in nature: a wide, super-thin disk being pushed by sunlight and moving 16 miles per second (26 kilometers per second) through interstellar space relative to the sun. The solar system, according to Loeb, was possibly being visited by an alien light sail — possibly one that had been thrown out like technological trash by an intelligent alien civilization. He has consistently defended this idea in the years since, even as the wider scientific community has settled on the view that the object was probably natural.
In”Extraterrestrial,” Loeb makes his case for the alien interpretation of’Oumuamua, while responding to the bulk of the scientific community which leans toward more mundane, natural explanations.
‘Oumuamua’s biggest anomalies, which Loeb says are most important to the case for its alien origin, are its shape, its shininess and the way it moved.
Without a clear image of’Oumuamua to use, astronomers were made to infer its form and size from its own light — both the intensity and how it quickly brightened and dimmed because it functioned once every seven or even eight hours. The significant gap between its brightest and dimmest expressions of sun directed early observers to conclude it is considerably longer than it had been wide and surprisingly bright, fitting no asteroid or comet ever seen in the solar panel.
That contributed into two possibilities: a unusually shiny, narrow cigar-shaped item, or a marginally smaller, exceptionally polished disk. Later research demonstrated that a disc was somewhat more likely based on the data, although the conventional view has tipped toward a cigar shape, which is easier to explain in nature, according to the two Loeb and other investigators who have looked at the problem.
The last anomaly, and the one Loeb sees as most important, was ‘Oumuamua seemed to accelerate as it moved away from the sun. A space rock moving only due to gravity shouldn’t do this, though a comet might. As the sun heats the side of a comet, gas bursts from its surface. That “off-gassing” can act like burning fuel that escapes from the bottom of a rocket engine, pushing a comet to higher velocities and new directions through space.
But the very precise telescopes trained on’Oumuamua didn’t observe a path of gas resulting away from the item, which could be expected in the aftermath of a normal comet. That, together with the probable disc shape, point to the item being mild sail driven by the sun, according to Loeb.
The device may not have been shipped deliberately into the solar system, he composed. On the contrary, it could be the garbage of a culture that produces huge numbers of machines that wind up drifting through space — the equivalent of technological garbage or”e-waste” on Earth.
“A buoy. A grid of pods for communication. Signposts that an extraterrestrial civilization could navigate by. Launch bases for probes. Other intelligent living organisms’ defunct technologies or discarded technological garbage,” he wrote. “These all are plausible explanations for the’Oumuamua mystery — plausible because here on Earth, humanity is already doing these things, albeit on a far more limited scale, and we would certainly consider replicating them if and when we explore out into interstellar space.”
In the years since, some scientists have provided different explanations for’Oumuamua’s anomalies. Maybe it’s a “cosmic dust bunny” made of some fluffy, ultralight material and light enough to be pushed by sunlight like a light sail. Maybe it’s a comet of nearly pure hydrogen, releasing molecules that would be invisible to telescopes. Loeb has sharply criticized these explanations, as Live Science previously reported. But now he says he appreciates that they at least treat’Oumuamua as a deep puzzle.
He reserves his sharpest criticism in the book for a”scientific establishment” engaged in”groupthink,” which he states is embodied by means of a paper published in the diary Nature at 2019 by the International Space Science Institute’s (ISSI)’Oumuamua team. The ISSI group, following months of careful study, concluded that it’s possible to explain the object’s properties through natural processes. For instance, they wrote, its off-gassing could have spewed unusually large dust particles that would have been counterintuitively difficult for telescopes to detect.
(Clouds of fine dust make smudges in the sky visible to telescopes in ways loose collections of bigger clumps are not. A comet known as 2P/Encke sometimes releases a similar form of difficult-to-spot dust, the researchers noted, for reasons unknown.)
They also said that’Oumuamua’s shininess wasn’t as anomalous as Loeb suggested, and really closely matched other tiny bodies in the solar system. In other words: a bizarre comet, but maybe not so bizarre a comet that it’s reasonable to assume that an alien source.
Loeb advised Live Science he’s been ridiculed for his stance on’Oumuamua, pointing to an article about his book published Jan. 4 in the Boston Globe, which quoted two critics, including one who suggested Loeb’s ideas risked making astrophysicists seem like”nutballs,” (the story did cite one physicist who called Loeb”brilliant”).
No one is similarly mocked, he said, for studying higher dimensions or string theory — both “esoteric” ideas never observed in the real world.
“Instead they get prizes or honors,” Loeb said, while young researchers are warned away from studying advanced alien civilizations in favor of less”taboo” fields which won’t hurt their careers. Astrobiology, the study of existence in space, is now taken seriously as a subject, he said. But cash flows toward searches for possible signs of microbial life that are unlikely to turn up definitive evidence of life — for example, the costly hunts for oxygen in exoplanet atmospheres. If oxygen is located, Loeb said, that will not prove life exists on alien worlds, because organic processes also create oxygen. Meanwhile, little cash goes to the search for advanced civilizations, he said, even though their signatures (such as industrial contamination in their atmospheres) are more conclusive.
Originally published on Live Science.