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3 months ago
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Teasing the public with fraudulent or self-deluded promises of aliens used to mean something. It took work. It meant slapping together ropes and planks of wood and trampling miles of barley in the dead of night, hundreds of times, over 13 years. It meant riveting 1/8th sheet steel into a 3 m-high monolith and depositing it in the Utah desert. Even theoretical works used to require huge leaps of logic and real effort: to turn 1I/’Oumuamua — a building-sized chunk of nitrogen ice — into a defunct solar sail from a network of interstellar buoys emplaced by a Galaxy-spanning civilization, or to misinterpret common seafloor iron-rich spherules as “steel-titanium alloys” likely from an “alien gadget”. In contrast, the latest release from Avi Loeb and collaborators — that maybe the interstellar comet 3I/ATLAS is alien technology — feels phoned in, like they’re just going through the motions. Where, I ask, is the dedication to the craft?
A hastily written article on a clickbaity topic, posted to arXiv by Loeb and collaborators, used to be something we could look forward to. ‘Oumuamua was discovered in 2017; within the year, Loeb was claiming it was an alien solar sail. Phosphine gas was tentatively detected in Venus’s atmosphere in September 2020 and got a lot of press; not a month passed before Loeb was speculating on the biomass and claiming bacteria could be “scooped up” and carried by meteors between Earth and Venus. If astronomers made a catalog of objects, you just knew he was going to see spaceships in them — whether an interstellar solar sail probe for the 2014 meteor in the CNEOS (Center for Near-Earth Object Studies) database, or the lost Venera 2 spacecraft for a dark comet. We’ve come to count on Loeb to turn legitimately exciting space discoveries into aliens, aliens, aliens with the regularity of movies in the Spider Man franchise.
And we expect those uploads to arXiv to be bold and inspirational. When confronted with his lack of understanding of how ice sublimates, Loeb didn’t pause, or stop at simply suggesting an artificial origin; he asserted “There is no doubt that the six peculiar features of ‘Oumuamua usher in a new era of space archaeology.” To conclude that the Chicxulub impactor had to be a comet, Siraj & Loeb (2021) needed to assume a comet would break into N ~ 10³ fragments. Comets passing by the Sun and Jupiter actually break up into N ≈ 20 fragments — as Figure 2 of the paper they cite makes super clear. So — unfettered by “physics” or “math” — they instead simply asserted that N ~ (1 AU / Dsun)¹°⁵ ~10³, with the comet breaking into a number of fragments dependent on the distance (1 AU) to Earth, a planet it didn’t know it might later collide with! Bravo!
Likewise, the velocity of the 2014 meteor appeared to be moving at 45 km/s, which is admittedly almost 25 km/s faster than the maximum speed it could have and be from our solar system. But the uncertainties in meteor velocities in the CNEOS catalog were already known to be up to ±28%, or ±13 km/s [Devillepoix et al. (2019)]. [Later, Brown & Borovička (2023) confirmed ±10–15 km/s for fast meteors like this one, and Hajdukova et al. (2024) confirmed greater than ±8 km/s for the catalog overall.] That would make the identification of the 2014 bolide as interstellar at best a 2- or 3-sigma result, meaning a 1-in-100 to 1-in-1000 chance of being from our solar system but so badly mismeasured. Because the CNEOS catalog has 1000 objects, it actually would be weird not to have so mismeasured at least one meteor. Undaunted, Siraj & Loeb (2022) dismissed the refereed literature and boldly claimed — based on talking to some guy¹ (personal communication with one Matt Heavner of LANL)— that the uncertainties were less than ±10%, or ±5 km/s. That would make the detection a 5-sigma event, making the 2014 meteor 99.999% likely to be interstellar. Then they got one Lt. Gen. John Shaw of Space Force to write a memo quoting that number. And now — the truly inspired part — Loeb cites Space Force as claiming it’s 99.999% likely to be interstellar (based on presumably classified knowledge). All without a single correct calculation! Well played!
But — just when you think they’ll zig, they zag! When informed the measured 4° inclination of Venera 2’s orbit is inconsistent with the orbit of the dark comet, Loeb suddenly and boldly favors large uncertainties!
All of this is the out-of-the-box thinking we need, to get results when the science gets hard or inconvenient. Don’t know how to calculate the fraction of Earth-crossing meteoroids that will collide with Venus? Follow the lead of Siraj & Loeb (2020), call it “1/3”, and don’t cite a paper or do math, simply cite “ssd.jpl.nasa.gov”. Like, someone at JPL knows, go ask them. I wish I had thought to teach my undergraduates such innovative techniques.
And, one more. Siraj & Loeb (2022) calculated the 2014 meteor broke up when subjected to 194 MPa of ram pressure. Most iron meteorites, with average compressive strength of 430 MPa (Petrovic 2001), would easily survive these pressures. But instead of, I don’t know, looking up this laboratory data, Siraj & Loeb stopped researching when they found that a crude approximation of this same data (Collins et al. 2005) implied iron meteorites break apart at only 50 MPa. That would then demand the 2014 meteor was made of something stronger than an iron meteorite. Hello, steel-titanium alloy of alien manufacture!
So, we’ve grown accustomed to the excitement and promise of aliens that comes from Loeb regularly misquoting the literature or warping statistics, and we expected nothing less after the announcement of the discovery of the third interstellar object, 3I/ATLAS. Like clockwork, “Is the Interstellar Object 3I/ATLAS Alien Technology?”, by Hibberd, Crowl & Loeb, dropped on the arXiv on July 17. But it’s not bold or inspiring.
It starts with a tired rehash of ‘Oumuamua. They claim “various anomalous features of this object have yet to be clarified”, especially the non-gravitational acceleration without observed outgassing. Actually we [Jackson & Desch (2021) ; Desch & Jackson (2021,2022)] have clarified the crap out of these features and there is not a single observation of ‘Oumuamua not explained by it being a chunk of N2 ice like that seen on the surface of Pluto. ‘Oumuamua was vaporizing but was simply too small for outgassing to be detectable. Interstellar space should have more than enough N2 ice fragments, especially from plutos around low-mass stars. But they decry the “bitter controversy” on the subject and sniff that their solar sail hypothesis wasn’t pursued (it was). Let it go, Drake. It’s just ice.
Next comes a by-now routine dismissal of astronomical observations, in order to claim 3I/ATLAS’s dusty coma (which does exist: de la Fuente Marcos et al.; Seligman et al.; Bolin et al.) does not exist and is just photographic fuzz. What would be bold and novel would be to lean in to the observations of dust and assert that any spaceship coming in hot from the interstellar medium would be very dirty and in need of a wash.
I’ll admit the background plot involving a paranoid alien race sending star-killing death probes to destroy us a la Cixin Liu’s The Dark Forest was not bad; but then where is the obvious comparison of the size of 3I/ATLAS with the volume of antimatter that would be needed to gravitationally unbind the Sun? [For the record: smaller than 3I/ATLAS, if composed of anti-neutronium]. In fact, the authors never seem to imagine technologically advanced star missiles being able to push themselves around our planetary system using anything but solar sails (these again!! yawn!), and they seem to think the probes would shyly wait until no one on Earth is looking to make some orbital maneuvers. As if our Mars probes wouldn’t be watching and posting video on the jumbotron of the Sun and probe getting cozy.
But the most unimaginative part of the whole paper is the statistics. The three interstellar objects to date have had orbits inclined to the ecliptic plane (in which our planets orbit) by 58°, 44°, and 5°. Pretty random, and 3I/ATLAS just happened to orbit near the ecliptic plane. Fun fact: Did you know that a comet flying in the plane of the planets’ orbits might pass by some planets?! Well, not all the planets. 3I/ATLAS does get kind of close to Mars and Jupiter, (and maybe-sorta) Venus, but manages to avoid Mercury, Earth, Saturn, Uranus, Neptune, and Pluto (they checked).
Seeing it passes by, let’s see, Mars and Jupiter, and then asking what are the odds it would have passed by Mars and Jupiter is really the same simple fallacy of seeing someone in the mall with a hat and then calculating how vastly improbable it is that you would walk by someone that exact instant… someone with a purple hat, which you’ve just decided is really important. Accounting for these sorts of things, the odds of 3I/ATLAS passing as close as it does to a few planets is disappointingly high (see more here).
Is this what counts as the best evidence for alien technology, “forcing the kind of question any self-respecting scientist has to address”? It’s a bigger letdown than The Matrix 2 and 3.
The authors conclude with a sobering dose of self-awareness (“The orbital path… could quite easily have been simple coincidence.” and “The propensity for the human brain to see patterns in what is actually random scatter is well known.”) that makes me realize their hearts just aren’t in it. Anymore it’s just basic reflex, stimulus-response. Stimulus (interstellar object) — response (alien technology).
But I have hope. The Vera Rubin Observatory is poised to discover dozens more interstellar chunks of ice like 1I/’Oumuamua, 2I/Borisov, and 3I/ATLAS this decade, so Loeb and company will have plenty of new blank canvases on which to project their confirmation biases for us, each with exciting new attributes that may inspire them to do so. Why does this one have the same reddish color as most comets and interstellar dust? Why does that interstellar object pass so close to Venus? Did it hear it might have phosphine? This other one very suspiciously didn’t pass by Mercury, why is that? That comet was found while the Moon was in the seventh house and Jupiter aligned with Mars! This other interstellar object reaches perihelion on somebody’s birthday? How did it know?! In other words, lots to work with.
And I know Loeb can do the work — making “Harvard astronomer” the scientific equivalent of “Florida man” didn’t just happen; it took long-term dedication. I want to believe Loeb and collaborators can delve once more into literature they aren’t familiar with, boldly ignore key papers and misquote others, tear down the barriers between science and sloppy statistics, and once again find bold and inspiring ways for aliens to be hiding under every asteroid, meteor and comet, all in the fashion to which we’ve all grown accustomed.
And I’ll be here to share the popcorn with you.
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