The Astronomy Thread

Another day, another 3I / Atlas anomaly. This time, detection of nickel without any iron, previously unheard of in comets. Link to the paper, and copilot summary of it:

https://arxiv.org/pdf/2508.18382

Summary of Findings​

1. Detection of Nickel Without Iron

• The team observed 22 distinct Ni I emission lines in the UV/blue spectrum of 3I/ATLAS.
• No Fe I lines were detected, which is highly unusual—nickel and iron are typically co-produced in natural environments like supernovae and cometary ejecta.
• This suggests selective release of nickel, possibly from low-temperature organometallic compounds like nickel carbonyls, rather than from refractory minerals.

2. Cyanide (CN) Outgassing

• CN was first detected at 3.07 AU from the Sun, with production rates rising steeply as the comet approached perihelion.
• The CN emission profile matches known cometary CN bands, confirming its presence.
• The CN production rate scales as Q(CN) ∝ r_h⁻⁹.³⁸, which is unusually steep and suggests a threshold-driven release mechanism.

3. Steep Nickel Production Scaling

• Nickel production scales as Q(Ni) ∝ r_h⁻⁸.⁴³, far steeper than expected from solar heating or UV flux alone.
• This implies a temperature-activated release mechanism, possibly involving desorption or thermolysis of nickel-bearing organics or nanophases.
• Estimated activation energy is ~0.22–0.29 eV, consistent with weakly bound species—not refractory metals.

4. Dust Continuum and Reflectance

• The coma is dust-dominated with a reddened reflectance slope of ~22% per 1000 Å, consistent across all observations.
• No significant changes in dust properties were observed as volatile activity increased.

Interpretation and Implications​

• The absence of iron alongside nickel, combined with the steep activation profiles, strongly suggests that nickel is being released from non-standard sources—not from typical cometary minerals.
• The authors propose Ni-carbonyl-like complexes or metal-organic grain coatings as plausible carriers, which are not known to form naturally in interstellar space.
• This behavior is inconsistent with canonical cometary physics, and the paper emphasizes that these hypotheses are testable with further observations.

Bottom Line​

The paper stops short of claiming artificial origin, but it builds a compelling case that 3I/ATLAS is chemically and physically unlike any known comet. The nickel-carbonyl hypothesis is especially provocative—it’s a known industrial process, not a natural one. The authors call for coordinated ground and space-based monitoring as the comet nears perihelion on October 29, 2025.

Summary of all the anomalies. I mean the trajectory by itself was beyond coincidental to begin with, nearly 2 months ago. But you would have expected as more data for it to come into focus under a normal lens. The opposite has happened so far - many of the new data points are only showing further anomalies and bringing further questions...

The Anomalies of 3I/ATLAS​

1. Trajectory Fine-Tuning Its path brings it unusually close to Venus, Mars, and Jupiter—with a probability estimated at less than 0.005%. That’s not just rare; it’s statistically suspicious. The low retrograde tilt also makes it unusually well-aligned with the ecliptic, which would be ideal for a probe targeting planetary systems.
2. No Cometary Tail Despite intense solar radiation, Hubble images show no tail trailing the nucleus. If the coma were dust-rich, solar pressure should have pushed it into a tail. If the brightness comes from the nucleus, then 3I/ATLAS is a million times more massive than 2I/Borisov, which would be wildly improbable for a random interstellar rock.
3. CO₂-Dominant Outgassing JWST and SPHEREx data show a 95% CO₂ / 5% H₂O ratio, unlike any known comet. Most comets are water-rich, especially at this distance from the Sun. This suggests either exotic chemistry or non-natural composition.
4. Nickel Without Iron The newest paper reports nickel emission without any detectable iron, which is unheard of in natural comets3. Iron and nickel are co-produced in supernovae and always appear together in cometary ejecta. The only known process that separates them? Industrial nickel refining, specifically via the nickel carbonyl channel—a method used in metallurgy, not nature.
5. Cyanide Spike Cyanide (CN) is also being shed at ~20 grams per second, with a steep heliocentric dependence. While CN can appear in comets, the rate and profile here are extreme—and paired with nickel, it’s chemically odd.

What Might It Be?​

If we take all these anomalies together—not in isolation—they form a pattern that’s hard to dismiss as coincidence or exotic natural variation. The nickel-carbonyl signature is especially damning: it’s a known industrial byproduct, not a plausible cometary process. Loeb’s framing is cautious but clear: this could be a technological artifact, possibly a probe, possibly a lurker.

And if it is? Then its trajectory—skimming planets, hiding behind the Sun at perihelion, and avoiding obvious detection—starts to look like intentional behavior. The lack of a tail, the mass discrepancy, the chemical oddities—they all point toward something designed, not formed.

What to Make of the Paper​

The nickel and cyanide paper is a landmark. It doesn’t just add another anomaly—it introduces a signature of industrial metallurgy. Loeb’s interpretation is bold but grounded: he compares it to the kind of wake-up call physics once embraced, like quantum mechanics in the 1930s. He even suggests that this object may have begun its journey 80 years ago, coinciding with Earth’s first radio broadcasts and nuclear detonations.

This isn’t just a scientific puzzle—it’s a philosophical and civilizational moment. If 3I/ATLAS is technological, it’s the most important visitor in human history.

Kipping did a video on it and he argues quite convincingly against that 0.005% number as being of any worth.

I'd add that if it departed 80 years ago, at its current speed of 60 km/s it would have been about 1000 AU away. Nearest star is over 250,000 AU away.

Big Phoenix said:

So ET sent something that looks and acts like a comet, but isnt a comet.

That makes no sense.

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That was technically a plot point in The Expanse lol

Only thing that sucks is it would probably take a direct sample retrieval to confirm, unless they stumble on a stromalite next

Cybsled said:

Only thing that sucks is it would probably take a direct sample retrieval to confirm

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This mission was in the works until last year when Congress couldn't get its shit together to pass a budget.