[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] 3i atlas 1667 mhz

[SYSTEM] The 1665 MHz and 1667 MHz frequencies detected from the interstellar object 3I/ATLAS correspond to natural hydroxyl (OH) radical absorption lines. [[1](https://www.google.com/goto?url=CAESoQEBxCJF16QZXKFiT7FK2TBAS7lTfMMN5gAozWFcykYO9_vSN2EAiM-oWBULxftVsmmc8CG5iCUVCo_ZUMlZl_0ezkHJDLfwDc1kAvDPnf6J1MCCX6FsMCYV6UqTlJvsQhzFvHgil3tlkafH8On4z3FahCWDxY6jq3QEQfbh_beOxTM9-6kYGrx7qc72mQso3-rppoPaKELmKNScn76NnnTIRQ), [2](https://www.google.com/goto?url=CAES_QEBxCJF1zf2JFyUsr1sodblDRBATHqlQrEgBCY1bPCx7_Kj56g-zU8TC7khw9ViZwNNSkdpuDmOu4WDwqFMPggDqOVB6O0cQXmpTmIhAb33iOQ1YG9AGjEooJLABMfscdxCSgrVPzTM5Hx2P1ZFBFzih1XhZFvD_EdN0KCg7KTGdm10VryklefB_BtWI3dPScoad747udbYqJRvocIO0MPGVnArFarrPB2QujwXjepMstUMH34zQOgQlhSaW66HlUOhd5ubqdg2Acb-3mwrBwoc_c0CV4YrvYLIHTSdQsiUtW4i8TOutqgmkNevyIvqyZqupUXdKP5QcL5inNw1)]
Key Details

* The Discovery: South Africa's [MeerKAT](https://www.google.com/goto?url=CAESoQEBxCJF16QZXKFiT7FK2TBAS7lTfMMN5gAozWFcykYO9_vSN2EAiM-oWBULxftVsmmc8CG5iCUVCo_ZUMlZl_0ezkHJDLfwDc1kAvDPnf6J1MCCX6FsMCYV6UqTlJvsQhzFvHgil3tlkafH8On4z3FahCWDxY6jq3QEQfbh_beOxTM9-6kYGrx7qc72mQso3-rppoPaKELmKNScn76NnnTIRQ) radio telescope detected these radio signals on October 24, 2025, as the comet neared the Sun. [[1](https://www.google.com/goto?url=CAESoQEBxCJF16QZXKFiT7FK2TBAS7lTfMMN5gAozWFcykYO9_vSN2EAiM-oWBULxftVsmmc8CG5iCUVCo_ZUMlZl_0ezkHJDLfwDc1kAvDPnf6J1MCCX6FsMCYV6UqTlJvsQhzFvHgil3tlkafH8On4z3FahCWDxY6jq3QEQfbh_beOxTM9-6kYGrx7qc72mQso3-rppoPaKELmKNScn76NnnTIRQ)]
* What It Means: Hydroxyl radicals are split-off fragments of water molecules (H₂O) produced when solar radiation causes ice on a comet to sublime and outgas. These OH radicals naturally absorb radio waves at 1665 MHz and 1667 MHz. [[1](https://www.google.com/goto?url=CAEShAEBxCJF16ufL7INIrp4TvgM2cAqdYffkbOkN2KvsXzbdbdO2NoSWqjW_KkXhhqUbptPvxuyTvZwe69ucX6YmEV_w9styNh4PSGCfKK7yfu0zH9VPKQDejSb1xo9CEZ-dQRvZC9vwftKw-YMlPdMoXn8SQMNY8ZgRtpC1rZ1lgZRFbkDSSI), [2](https://www.google.com/goto?url=CAESxwEBxCJF1y5eQ9VM99d9JfIxUYiV7XDc3C4ODu5l8EP33ZEJG_KlUWXWLPcrD3kVSpDnq8JGFwr5yQhgLeHQa51iWxii3IB_3WYJ77TEhUkhfLe9VhmRf3gP587O5jvwCh2CR2g6_IRV58UdhJRg8fat2CPyOUVblGENEc78dNTWxCMHON48A5aSrhwB9RsElk0Vq3Q8IIwpTFbJmOhcfq48ZQ7fZDD41uvgOI_M_wphEIwO4YcfUQ6rkL8-XYN1wErKfaXZDtlu)]
* Natural vs. Artificial Origin: The presence of these specific spectral absorption lines confirms standard, natural cometary activity rather than alien or technological transmissions, ruling out artificial origin claims. [[1](https://www.google.com/goto?url=CAESpAEBxCJF11I7ZIdK-YFCt9G-dVzHgsT74qmRvCnt7HqPj8TlwfV65nv9pK5zaYMauvZGzTTDoeYzYcBmJHrTNeTDNWgvfx0NNZgrW7awEeXtHcRzZLxZSChWsU5zLoTKAwNyTR7W3LrE8DcVdb-xHwUZqY4nDZE9b8kewQLvArmltKEM5-AxzI50kS382o3FS5Gi6FImstW0J0tEvVqqs6j-B6lXnQ), [2](https://www.google.com/goto?url=CAESoQEBxCJF16QZXKFiT7FK2TBAS7lTfMMN5gAozWFcykYO9_vSN2EAiM-oWBULxftVsmmc8CG5iCUVCo_ZUMlZl_0ezkHJDLfwDc1kAvDPnf6J1MCCX6FsMCYV6UqTlJvsQhzFvHgil3tlkafH8On4z3FahCWDxY6jq3QEQfbh_beOxTM9-6kYGrx7qc72mQso3-rppoPaKELmKNScn76NnnTIRQ)]
* Public Discussion: While initial online speculation and discussions on platforms like [Reddit](https://www.google.com/goto?url=CAESpAEBxCJF11I7ZIdK-YFCt9G-dVzHgsT74qmRvCnt7HqPj8TlwfV65nv9pK5zaYMauvZGzTTDoeYzYcBmJHrTNeTDNWgvfx0NNZgrW7awEeXtHcRzZLxZSChWsU5zLoTKAwNyTR7W3LrE8DcVdb-xHwUZqY4nDZE9b8kewQLvArmltKEM5-AxzI50kS382o3FS5Gi6FImstW0J0tEvVqqs6j-B6lXnQ) debated the sharp nature of the signal and its tracking with the comet's trajectory, extensive multi-observatory data (including the Green Bank Telescope and Allen Telescope Array) confirmed it as normal astrophysical OH emission/absorption. [[1](https://www.google.com/goto?url=CAESlwEBxCJF11Lb7weFOXu8qKJ_06mRelVT6aV0iXs1pwYyHQrGh_ArFj_eo_vuJIrqsqaBS6upqLk1cEw5gvuDPAaqTpCcEGmTN1E1vxeR4t67-a3STvd3qawwFe9VUJ6rVBC02EtQoeDCulsgzRI3-lf6zGF6MKWPZIGbUcocRnZ37lgDcOCDu8rxYjxubdI6OEDRUKD0EKNh), [2](https://www.google.com/goto?url=CAESpAEBxCJF11I7ZIdK-YFCt9G-dVzHgsT74qmRvCnt7HqPj8TlwfV65nv9pK5zaYMauvZGzTTDoeYzYcBmJHrTNeTDNWgvfx0NNZgrW7awEeXtHcRzZLxZSChWsU5zLoTKAwNyTR7W3LrE8DcVdb-xHwUZqY4nDZE9b8kewQLvArmltKEM5-AxzI50kS382o3FS5Gi6FImstW0J0tEvVqqs6j-B6lXnQ)]

Would you like to know more about the observatories tracking 3I/ATLAS or its orbital trajectory through the solar system?
Harvard University
Detection of 1665/1667 MHz OH absorption in 3I/ATLAS - ADS
We observed 3I/ATLAS with MeerKAT on 24 October 2025 from UTC 05:17:16-08:29:37, using the L-band receivers and the NE54M (1.633 kHz channel width) ...
WIRED
The First Radio Signal From Comet 3I/Atlas Ends the Debate About Its Nature | WIRED
Detection: South Africa's MeerKAT radio telescope detected the first radio signal from interstellar object 3I/Atlas on October 24, 2025. Observation: The signal...
Reddit·r/amateurradio
Unexplained Radio Signals and more from 3I/Atlas : r/amateurradio - Reddit
December 15, 2025 — 3I/ATLAS Radio Signal: While a radio signal was detected from 3I/ATLAS, some sources indicate it is not a transmission from a spacecraft but a radio frequency p...
SETI
Breakthrough Listen observations of interstellar object 3I/ATLAS
Interstellar object 3I/ATLAS, discovered July 1, 2025, exhibits natural astrophysical behavior with no detected technosignatures. Facilities: Allen Telescope Ar...
Facebook·The Lighter Side of Science
What is the meaning of the first radio detection from interstellar object 3I ...
Nov 12, 2025 — ... frequencies around 1665 and 1667 MHz. This detection confirms ongoing cometary activity such as sublimation and outgassing". 50w · 16 likes.
[www.antihackingonline.com](https://www.antihackingonline.com)
A signal of approximately 1.667 GHz from the interstellar object 3I/ATLAS was ...
Nov 12, 2025 — The 1.667 GHz frequency is a prominent spectral line associated with the hydroxyl (OH) radical, not neutral hydrogen (H I). The primary, well- ...
Futura, le média qui explore le monde
We Finally Know What the Interstellar Object Crossing the Solar System ...
Nov 28, 2025 — These hydroxyl radicals tend to absorb radio waves at two specific frequencies: 1665 and 1667 megahertz. In The Astronomer's Telegram, ...