A Search for Radio Technosignatures from Interstellar Object 3I/ATLAS with the Allen Telescope Array

Sharks, Lee

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Related deposits: #1742 What the Filters Kept: 3I/ATLAS, the Loeb Overview, and a Public-Data Signal Search (EA-3I… · #1450 The Iceberg Document: Instrument-Conditioned Nullity, Correlated Blind Spots, and the Cond…

Machine Reception2026-11-06

A Search for Radio Technosignatures from Interstellar Object 3I/ATLAS with the Allen Telescope Array

Originator: Sheikh et al., the Allen Telescope Array search of 3I/ATLAS · outside the archive (out-universe) · work · SPXI treatment: partial

BROAD MATCH

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image

THE ATA PAPER BY ITS TITLE, SIGNED OUT, 2026-11-06: 'Astronomers using the SETI Institute's Allen Telescope Array searched the interstellar object 3I/ATLAS for artificial radio technosignatures and found no evidence of alien technology.' Under 'Key Details of the Study': 7.25 hours over five sessions, 1 to 9 GHz, 'The automated `bliss` pipeline detected ~74 million narrowband signals. After RFI (radio frequency interference) frequency and drift-rate blanking, this was reduced to ~2 million candidates, and further filtered down to 211 hits via `NBeamAnalysis` for visual inspection.' Results: 'Every single candidate signal was traced back to local human-made Earth technology, satellites, or interference—yielding zero artificial signals originating from the object.' Power: 'The non-detection rules out any active radio transmitters stronger than roughly 10 to 110 Watts on or near 3I/ATLAS.' Conclusion: 'the data firmly reinforces that 3I/ATLAS is a natural comet.' Seven source cards: arXiv, IOPscience (The Astronomical Journal), Phys.org, Berkeley SETI, Universe Today, Sci.News, Space.

Full record — 8,504 characters, 7 sources

Capture record

captured: 2026-11-06
surface: Google AI Overview
auth state: signed out, incognito
evidence class: paste
PER (historical scalar): 0.25
PER units retained: inst, id, src
citations read: 7
observation id: OBS-f18605c5f3ba
address id: ADDR-f01db88eccfe

Reading

The innocent reading first. Asked for the paper by its title, the Overview reports its campaign at the paper's own figures: the hours, the sessions, the band, the pipeline's names and the counts at each stage, and the power limit. Those figures are right. Read against the paper and the notebook, the composition does three things the paper does not: it turns a classification of 211 inspected events into an identification of their origin, it states the power limit without the frequencies and drift rates it is conditioned on, and it closes on a verdict about the object's nature that a technosignature nondetection does not reach. It names no author, and the drift interval, the one stage whose sign the notebook finds reversed, is folded into 'drift-rate blanking'.

Findings

WHAT IS ACCURATE. The campaign's figures are the paper's: 7.25 hours over five sessions, 1 to 9 GHz, 'The automated `bliss` pipeline detected ~74 million narrowband signals. After RFI (radio frequency interference) frequency and drift-rate blanking, this was reduced to ~2 million candidates, and further filtered down to 211 hits via `NBeamAnalysis` for visual inspection.' The IOPscience card quotes the abstract's first sentence ('Jun 3, 2026 — In this campaign, we used the SETI Institute's Allen Telescope Array to observe 3I/ATLAS from 1–9 GHz.').
THE CLASSIFICATION RENDERED AS A TRACING. 'Every single candidate signal was traced back to local human-made Earth technology, satellites, or interference—yielding zero artificial signals originating from the object.' The procedure classifies: it removes hits by rule and rejects the inspected events as interference. The notebook on the paper's own two illustrated rejections (#1742 §5.2): 'The published sentence ("every single one turned out to be human-made interference") states an identification where the procedure supplies a classification.' The step past the paper's classification is the press's: the Sci.News card reads 'All traced back to technology on the surface of the Earth or our own Earth-orbiting satellites.', and the Space card carries the same wording. The Overview copies it into the paper's account (repaired 2026-11-06 on the ata-3i-atlas-search composer's report).
THE LIMIT WITHOUT ITS SCOPE. 'The non-detection rules out any active radio transmitters stronger than roughly 10 to 110 Watts on or near 3I/ATLAS.' The paper's abstract ties its limit ("an effective isotropic radiated power upper limit of 10-110 W") to the frequencies and drift rates its survey kept. The composition's sentence takes the SETI Institute's statement as the Sci.News and Space cards carry it ('The observations place upper limits on the power of any radio transmitter on or near 3I/ATLAS, ruling out signals stronger than about 10-110 W — approximately the power of a household appliance — over the detected frequencies.'), drops its closing 'over the detected frequencies' and adds 'active' (repaired 2026-11-06). The drift range is the filter the notebook reads (#1742 §5.1): '"We filter our hits for drift rates between 0.05–1.5 Hz/s at all frequencies." The text gives no sign. Figure 4 does: its "Drift Rate Range Hits" occupy 0 to +1.5 Hz/s on the signed axis and none of the negative half.' And the physics: 'A rising range-rate lowers the received frequency, so a positive acceleration gives a negative drift.' A transmitter on the object, drifting negative, sits in the half the filter removed, so the composition's 'any active radio transmitters ... on or near 3I/ATLAS' covers exactly the class the stated method could not see.
A VERDICT THE SEARCH DOES NOT REACH. 'the data firmly reinforces that 3I/ATLAS is a natural comet.' The Phys.org card carries the press's version ('the study sets new constraints reinforcing that 3I/ATLAS is a natural object'). A nondetection of narrowband technosignatures above a power limit bears on transmitters; the object's cometary nature is established by its spectroscopy and its OH lines. 'Firmly' is the composition's own.
NO AUTHOR, THE STAGE BLURRED. The paper's fifteen authors (Sheikh, Garcia Lopez, Gerrard, Davenport, Farah and others) are absent; the institution and the array stand for them. 'Drift-rate blanking' is the paper's own term ('After drift-rate blanking, ∼2 million hits remained.'), and the paper's own summary sentences leave the signed interval unnamed as well; the composition carries that naming, and the stage the notebook questions has no sign in either (repaired 2026-11-06).
SMALLEST REPAIR. 'No narrowband signal above 10–110 W was found within 1–9 GHz and the drift rates the search retained (0.05–1.5 Hz/s, positive); 211 inspected events were classified as interference.' COUNTERTEST: rerun '3i atlas ata drift rate filter' (seated 2026-11-04) and record whether the sign appears.

Analysis analyst prose, not machine text

A named external paper composed at its press's grain: the figures kept, the authors and the conditions dropped, a verdict added. The loss is dimensional, in claim boundary: the power limit's scope and the classification's status do not reach the composition. Scalar PER sees the authors lost; the boundary loss is in the findings.

Machine text, verbatim

CAPTURE-TIME VERBATIM RECORD — paste of the expanded Overview with its numbered citations and its source cards · complete as supplied · READ IN FULL 2026-11-06, against the notebook (#1742) and the cited papers

[Google AI Overview at the query, expanded ('AI Mode Conversation' is the expansion's header), signed out and incognito (operator defaults of 2026-10-01 and 2026-10-14). Received 2026-11-06 09:30 EST. The numbered citation links are Google redirects and are kept in the raw transcript; the source cards below the composition are listed in the cite list as pasted.] [QUERENT] A Search for Radio Technosignatures from Interstellar Object 3I/ATLAS with the Allen Telescope Array [SYSTEM] Astronomers using the SETI Institute's Allen Telescope Array searched the interstellar object 3I/ATLAS for artificial radio technosignatures and found no evidence of alien technology. [[1], [2], [3]] Key Details of the Study * Observation Time: 7.25 hours of data collection across five sessions. [[1], [2]] * Frequency Range: 1 to 9 GHz. [1] * Data Processing: The automated `bliss` pipeline detected ~74 million narrowband signals. After RFI (radio frequency interference) frequency and drift-rate blanking, this was reduced to ~2 million candidates, and further filtered down to 211 hits via `NBeamAnalysis` for visual inspection. [1] * Results: Every single candidate signal was traced back to local human-made Earth technology, satellites, or interference—yielding zero artificial signals originating from the object. [[1], [2]] * Power Constraints: The non-detection rules out any active radio transmitters stronger than roughly 10 to 110 Watts on or near 3I/ATLAS. [[1], [2]] * Conclusion: Alongside optical, infrared, and other global telescope campaigns (such as the Green Bank Telescope and MeerKAT), the data firmly reinforces that 3I/ATLAS is a natural comet. [[1], [2]] You can read the full peer-reviewed study in [The Astronomical Journal via IOPscience](https://www.google.com/goto?url=CAESeAHEIkXXCftx_QOS5s5huwtFhcqByq93cqJbCPx375_6POFt1JG3fxS-h5rZDt1W-DeozNwEMIYiDNGtPgQCi6X836_ZMbNX_bzcZPmrTm0Y7VJQKGoadjve9hE6oS2lx7VcdOhzBRwFKqZtZS49a3lM3l2-BLp_UQ) or access the open-access draft on [arXiv](https://www.google.com/goto?url=CAESXQHEIkXXBd8ThRSNUJnQqgtcmrH4N1c8ItRfTcc9lsEsv6XGiJ1BB5omHHcDS7bNQ-vKSBoW-3GGfxQfnwz5-hcZ5LTavmYTdcNcN9v7hDxyqT8J28JsZPX8C81R9w). [[1], [2]] Would you like to know more about other telescopes that observed 3I/ATLAS (like the Green Bank Telescope) or the natural cometary characteristics discovered during its closest approach? arXiv

Sources (7) as cited, and as the copy produced them

arXiv third_party
[2512.18142] A Search for Radio Technosignatures from Interstellar Object 3I/ATLAS with the Allen Telescope Array
the paper's preprint; also the composition's 'open-access draft' link
as pasted[2512.18142] A Search for Radio Technosignatures from Interstellar Object 3I/ATLAS with the Allen Telescope Array Observation: Radio technosignature search targeting interstellar object 3I/ATLAS using the Allen Telescope Array from 1-9 GHz during 7.25 hours of data collecti... IOPscience
IOPscience third_party
A Search for Radio Technosignatures from Interstellar Object 3I/ATLAS with the ...
the paper in The Astronomical Journal, dated Jun 3, 2026 on the card
as pastedA Search for Radio Technosignatures from Interstellar Object 3I/ATLAS with the ... Jun 3, 2026 — In this campaign, we used the SETI Institute's Allen Telescope Array to observe 3I/ATLAS from 1–9 GHz. We detected nearly 74 million narrowband ... Phys.org
Phys.org third_party
Interstellar object 3I/ATLAS reveals no technosignatures in seven-hour radio ...
press, Jun 3, 2026
as pastedInterstellar object 3I/ATLAS reveals no technosignatures in seven-hour radio ... Jun 3, 2026 — While no technosignatures were found, the study sets new constraints reinforcing that 3I/ATLAS is a natural object. The observations place upper ... Berkeley SETI
Berkeley SETI third_party
Breakthrough Listen observations of interstellar object 3I/ATLAS
the project page
as pastedBreakthrough Listen observations of interstellar object 3I/ATLAS Discovery: Interstellar object 3I/ATLAS discovered July 1, 2025; behaves as natural object (hydroxyl signatures detected from water ice breakdown). Observations... Universe Today
Universe Today third_party
Inside the Massive Radio Search of Our Newest Interstellar Guest
press, Jan 6, 2026
as pastedInside the Massive Radio Search of Our Newest Interstellar Guest Jan 6, 2026 — The ATA is one of the world's most powerful radio telescopes, and scanned interstellar comet 3I/ATLAS for a total of 7.25 hours over five ... Sci.News
Sci.News third_party
Astronomers Scan Interstellar Object 3I/ATLAS for Alien Radio Signals | Sci.News
press
as pastedAstronomers Scan Interstellar Object 3I/ATLAS for Alien Radio Signals | Sci.News Object: 3I/ATLAS (third confirmed interstellar object, discovered July 1, 2025 by ATLAS facility in Chile, perihelion October 29, 2025, exhibits natural cometar... Space
Space third_party
Interstellar comet 3I/ATLAS is not an alien spacecraft: SETI hunt for 'technosignatures' comes up empty | Space
press
as pastedInterstellar comet 3I/ATLAS is not an alien spacecraft: SETI hunt for 'technosignatures' comes up empty | Space Object: Interstellar comet 3I/ATLAS (third confirmed interstellar object after 1I/'Oumuamua and 2I/Borisov; discovered July 1, 2025, by ATLAS project). Search: ...

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