Harvard astronomer Avi Loeb shocked the world in 2017 when he announced his belief that Earth received its first alien visitor. Astronomers agreed that ‘Oumuamua, the object that hurtled past Earth at 200,000mph, came from beyond the solar system. However, Loeb extended its uniqueness further: he thought it was an alien civilization’s lost technological relic.
The media all but pounced on the story, focusing on his Harvard title and eye-catching quotes. In 2021, he published his book Extraterrestrial: The First Sign of Intelligent Life Beyond Earth. In it, he explained his reasoning, summarized as follows:
‘Oumuamua’s oscillating brightness indicated it had a long cigar-like structure, extremely rare in the known population of space objects.
Its orbit deviated with behavior unlike that of comets (which can sometimes eject gas and accelerate).
Its surface was unusually shiny.
Multiplying these statistical anomalies together, ‘Oumuamua is approximately a “one-in-a-million object”.
Loeb had previously worked on a privately-funded project called Breakthrough Starshot, which imagined “lightsails”: giant, thin mirrors that accelerated by receiving the sun’s light energy. ‘Oumuamua’s high reflectivity, strange brightness, and acceleration would make sense if it was a lightsail, said Loeb in his book. Though the theory received widespread skepticism from the scientific community, with many believing he was jumping to conclusions with the yet-unexplained acceleration, Loeb has maintained his position throughout the years.
Now, the researcher has gained the spotlight once again. He says in his blog that the “spherules of sub-millimeter size” (Loeb 2023) he found on the ocean floor are from a 2014 interstellar meteor. He raises the different elemental composition of the “spherules” than the background samples as evidence, but astronomers are dubious once again. They doubt that such a fast meteor would've survived the Earth's atmosphere at all. Peter Brown of the University of Western Ontario told Space.com that "[a]ny solids that would remain would be essentially aerosol-size” (Tingley 2023), far smaller than how Loeb describes the fragments.
In the case of ‘Oumuamua, I argue that progressing its classification from an interstellar body to alien technology is nothing more than a thought experiment. Loeb has no more data on the interstellar object than any other experienced planetary astronomer. Yet, in his book, he paints himself as a martyr who stands alone against deniers refusing to seek the truth about ‘Oumuamua.
A segment from a 2021 public talk reflects continuity in Loeb’s attitude toward the scientific response to his claims. Jill Tarter, a 40 year-experienced SETI scientist, refuted Loeb's comments about SETI research being too cautious, stating that claims of first contact would always require "extraordinary evidence". Loeb acts petulantly in response, avoiding Tarter’s points with unrelated arguments about string theory research funding. Here's the exchange below:
Although he’s issued an apology for his behavior, it’s frankly embarrassing and difficult to even watch through. He makes extraordinary claims that are only backed by basic evidence and opposes critics as being too conservative and hardheaded. Additionally, he ignores Tarter’s appeals to her work in SETI, seemingly accusing her of not doing enough for the field (as if anyone else has possibly done more). By the end of the segment, he points a finger at Tarter and makes a high-pitched mockery of her words while she remains collected, refuting his accusations.
This is the person appearing on television or podcasts promoting SETI and astrobiology. When Avi Loeb makes extraordinary claims out of insufficient evidence, that is the impression the public gets of the field. I’d know—I was one of those people. I adored Loeb when I first read Extraterrestrial on the steps of the Columbia University library, believing him to be an unsung hero for the science that I dreamt of studying. Not knowing then about the thousands of scientists conducting reputable research in the field, I adopted his claims about ‘Oumuamua (and implied moral/intellectual superiority of his scientific philosophy) as my own.
I realize now that Loeb’s attitude undermines the legitimate work the astrobiology community has done to counteract the “alien” stigmatization from UFO conspiracists. It is counterintuitive in convincing important funders of the scientific method’s rigor and threatens further deterioration of the field’s reputation in science.
Of course, the burden of this grand venture does not fall solely on Loeb being more responsible. The media must also do its duty to fully explain Loeb’s claims and their uncertainties. The Forbes piece linked above is an excellent example of one that includes thorough research. When we can reconcile human interest with accurate science journalism, I hope the public understands SETI’s potential radical effect on human civilization. Contact with a culture completely independent of human cultural development would be nothing short of revolutionary, both for our self-perception in the cosmos and expansion of scientific knowledge.
“Compared to some flights of theoretical physics,” Avi Loeb says in Extraterrestrial, “the search elsewhere in the universe for something that is known to exist on Earth… is a conservative line of inquiry”. Indeed it is, and I will continue to defend its legitimacy within science. But as much as proponents of SETI are passionate about the field, we must be careful to approach that inquiry with rigorous methods and a healthy dose of self-reflection.
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Works Cited
In Depth | Oumuamua – NASA Solar System Exploration. (2019, December 19). NASA Solar System Exploration. https://solarsystem.nasa.gov/asteroids-comets-and-meteors/comets/oumuamua/in-depth/#:~:text=9%2C%202017%20at%20a%20blistering,behaves%20more%20like%20a%20comet.
Tingley, B. (2023, July 20). Interstellar meteor fragments found? Harvard astronomer’s claim sparks debate, criticism. Space.com; Space. https://www.space.com/interstellar-meteor-avi-loeb-expedition#:~:text=Avi%20Loeb%20is%20back.,refers%20to%20as%20%22IM1.%22
Loeb, A. (2023, July 3). Summary of the Successful Interstellar Expedition - Avi Loeb - Medium. Medium; Medium. https://avi-loeb.medium.com/summary-of-the-successful-interstellar-expedition-61ff4467070d
Siegel, E. (2021, February 16). Watch: Harvard Astronomer Mansplains SETI To The Legend Who Inspired Carl Sagan’s Contact. Forbes. https://www.forbes.com/sites/startswithabang/2021/02/16/watch-harvard-astronomer-mansplains-seti-to-the-legend-who-inspired-carl-sagans-contact/?sh=a6ec31c620b8
Loeb, A. (2021). Extraterrestrial: The First Sign of Intelligent Life Beyond Earth. Houghton Mifflin.
Wright, J. (2023, July 18). Avi and Oumuamua: Setting the Record Straight. Pennsylvania State University. https://sites.psu.edu/astrowright/2023/07/18/5202/
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