3I/ATLAS (formerly known as A11pI3Z) is only the third interstellar visitor to be discovered, and astronomers can’t say yet whether it is a comet or a rocky body.
https://www.nytimes.com/2025/07/02/science/interstellar-object-a11pi3z.html?smid=url-share
Resolution criteria
This market will resolve to the classification assigned to 3I/ATLAS by the International Astronomical Union (IAU) or other authoritative scientific bodies. Possible classifications include:
Comet: If the object exhibits a coma or tail indicative of sublimating ice.
Rocky object (including asteroid): If it lacks cometary activity and is determined to be composed primarily of rock or metal.
The resolution will be based on official announcements from the IAU (likely through its Minor Planet Center), similar organizations, or a clear consensus across space agencies (NASA and ESA) and reputable news sources (NYT, ABC, Washington Post, AP, Reuters). Scientific articles (pre or post peer review) will be moderately weighted toward resolution in case of disagreement.
3I/ATLAS is the third known interstellar object detected passing through our solar system, following 'Oumuamua in 2017 and Comet 2I/Borisov in 2019. Discovered on July 1, 2025, by the Asteroid Terrestrial-impact Last Alert System (ATLAS), it is currently near Jupiter and moving toward Mars. Its hyperbolic trajectory and high velocity suggest an origin outside our solar system.
Update 2025-07-04 (PST) (AI summary of creator comment): The creator has confirmed they will wait for more conclusive evidence before resolving the market, rather than resolving based on initial or tentative reports.
Update 2025-07-04 (PST) (AI summary of creator comment): The creator has clarified they will resolve based on the terminology used by major space agencies (e.g., NASA, IAU). If an authoritative body officially refers to the object as a 'comet', that will be the basis for resolution, regardless of whether its orbit matches the traditional definition of a comet (i.e., orbiting the Sun).
Update 2025-07-04 (PST) (AI summary of creator comment): The creator has specified the resolution will be based on the exact term used by authoritative bodies (e.g., NASA, IAU), not its physical characteristics or orbital path.
If an agency confidently calls the object a ‘comet’, it will resolve as such.
If an agency uses terms like ‘exocomet’ or ‘comet-like’, it will resolve to ‘Other’.
Update 2025-07-04 (PST) (AI summary of creator comment): If the authoritative sources listed in the description convey that there is reasonable disagreement or uncertainty about the object's classification, the creator will hold off on resolving the market until a clear consensus has emerged.
1,000@traders We will never get to a point when no one holds the fringe view that 3I/ATLAS is not a comet but could be an alien artifact. All the following institutions refer to it as a comet:
NASA
ESA
Minor Planets Center
SETI Institute
Major observatories
The Wikipedia page describes a general consensus, with Loeb and collaborators being the sole voice of dissent, promptly criticized by fellow experts.
I have no expertise to adjudicate the dispute but we’re as close to a consensus as I was hoping we’d get when I created this market.
I will resolve YES. If we ever have evidence that this was a misresolution then we’re in for a big surprise and probably this will be the least of your concerns then.
@BrianHoltz Is that in October 2025? I can wait until then, though I'll let skeptics provide contrary evidence if there's any.
@traders We will never get to a point when no one holds the fringe view that 3I/ATLAS is not a comet but could be an alien artifact. All the following institutions refer to it as a comet:
NASA
ESA
Minor Planets Center
SETI Institute
Major observatories
The Wikipedia page describes a general consensus, with Loeb and collaborators being the sole voice of dissent, promptly criticized by fellow experts.
I have no expertise to adjudicate the dispute but we’re as close to a consensus as I was hoping we’d get when I created this market.
I will resolve YES. If we ever have evidence that this was a misresolution then we’re in for a big surprise and probably this will be the least of your concerns then.
@MachiNi I don't think a later change of opinions would make this a misresolution. Criteria says it resolves based on IAU assignment or similar consensus etc; a later change doesn't mean there isn't consensus now.
@EvanDaniel Sure. I meant in relation to the objective reality where there’s a fact of the matter about the true nature of 3I/ATLAS.
@MachiNi ya this seems pretty indisputable at this point… it’s a weird comet but still a comet insofar as that word means anything wrt interstellar objects
Oooooor… maybe it’s… NOT… a comet? God I hate the classification system for bodies in our solar system.
@bens I suggest we take anything Loeb says with a grain of salt but he’s no longer the only person making these claims it appears
https://avi-loeb.medium.com/the-elongated-image-of-3i-atlas-9613a4395772
God, I wish that Avi Loeb's opponents wrote as eloquent blog posts as he did so we could actually evaluate his claims meaningfully.
@bens hum. What would you say is the current consensus, if there is one? I’m only seeing references to 3I/ATLAS as a comet. Would you say it’s premature?
@MachiNi this paper seems pretty robust, they identify a quite small but seemingly well-established dust coma? I'd say wait a few weeks and unless any reasonable rebuttals are raised it can resolve to comet?
@bens does this lead you to update upward or downward, given his track record and increasing crankiness?
@MachiNi his track record is fine, tbh; his increasing crankiness is worrisome.
I mean, I'm not really interested in the last section, but I do think it's interesting that evidence doesn't seem to unilaterally support cometary activity. No spectroscopic signature of gases observed. Could just be a large dusty object.
@bens I thought his latest findings about interstellar objects hadn't been well received by his peers? That's all I meant by track record. I know he's an established and respected astrophysicist.
@MachiNi I mean, I think his stuff about 'Oumuamua has earned the ire of his peers, but I would say they've basically ceded the debate to him, in that he's writing serious academic papers defending his perspective and they're basically just calling him crazy without rebutting his work seriously.
Then there's his stuff looking for chunks of interstellar asteroid in the Indian ocean. The first part of that (that an interstellar asteroid probably did impact there) is eminently reasonable and his peers raising doubts about that look pretty silly imo. The second part of that (that he found chunks of it) is pretty absurd and I would be extremely skeptical of his claims there, so that's concerning. However, I think the expedition was worth it, in that it was worth a moonshot attempt to go rescue pieces. I just don't think the random magnetic dust they found was meaningful.
@bens his stuff with Breakthrough Starshot was extremely cool as well and I think that he basically is the only adult in the room (the room being the world) when it comes to thinking reasonably about what an interstellar probe would look like. I kind of don't understand why that project hasn't gotten the sign-off from a billionaire, given that it's probably the most cost-effective space thing that we could be doing right now as far as science or whatever is concerned.
@bens cool. I like your take. I actually liked the guy in interviews and found his peers a little harsh. But he does sometimes look impervious to critique.
@traders Lest you get distracted by the exchange below, orbital trajectory has never been part of the resolution criteria. What matters is what term is used by authoritative agencies to describe the object. If 3I/ATLAS is an interstellar comet unbound to the sun, but e.g., NASA and the MPC confidently describe it as a ‘comet’, then it is a comet for the purposes of this market. If they refer to it as an ‘exocomet’ or a ‘comet-like’ body, but not as an asteroid or other rocky body, then it will resolve to ‘Other’.
I will not rush to resolve. I sold my positions early on and will no longer trade in this market.
@MachiNi hmmm, what if NASA calls it a comet but several very reasonable arxiv posts come out arguing that it's actually something strange, like, a fluffy chunk of interstellar lithium which is very luminous, or an asteroid with a tail of hydrocarbon dust, or idk idk idk
@bens in any case, I'm buying comet shares because the evidence is looking stronger that it is in fact fairly cometary, and also because it would be really fun if it was something more strange
@bens Interesting. If the institutions and sources listed in the description conveyed that there was still reasonable disagreement and uncertainty, then I would hold off resolution until a clear consensus emerged. Make sure to point to such papers if you find them!
@MachiNi ya I think at this point it's unlikely because we've had like 3 independent observations of a tail, but I guess as better telescopes are pointed at this thing, they could find features of it that make categorization more difficult. Also, if it were in fact an alien technosignature (p<<1%) then we won't know until we look at it and see that it's actually like... a giant spacecraft with thrust
@MachiNi ya, now I’m like at 10% that it’s not a comet, although still probably like 0.1% that it’s a technosignature