Arecibo message

|access-date=2022-05-13}}</ref><ref>{{Cite web|title=Is the Latest Crop Circle a Message from E.T?|publisher=[[SETI|SETI Institute Online]]|work=General Information |url=http://seti.org/general/ao_message_crop.html|archive-url=https://web.archive.org/web/20041013062350/http://seti.org/general/ao_message_crop.html|archive-date=2004-10-13|access-date=2019-11-18}}</ref> The crop circle is a near replica of the Arecibo message, with the same 23 × 73 grid. Most of the chemical data remains the same, with the exception that in the section detailing important chemical elements, [[Hypothetical types of biochemistry#Silicon biochemistry|silicon]] has been added, and the diagram of DNA has been rewritten. At the bottom, the pictogram of a human is replaced with a [[grey alien|figure with a large, bulbous head]].<ref>{{cite web|url=https://qrius.com/arecibo-message/|last=Chitnavis|first=Urvashi|title=The Arecibo Message: What happened when humanity tried to communicate with aliens|date=2018-03-30|website=Qrius|language=en-GB|access-date=2019-11-18}}</ref><ref name="Griffin2018" /> A solar system with 9 planets is also depicted, with emphasis placed on the 3rd, 4th, and 5th planets of the system. The Arecibo telescope is replaced by a replica of a crop circle that appeared in the same field one year before, and the binary representation of the transmitter's diameter is altered.<ref>Schnabel, Jim (2002-08-08). "Top of the crops 2001". ''Circlemakers''. (''circlemakers.org/totc2001.html'').</ref><ref>{{Cite web|title=The Chilbolton 'Arecibo message' Formation| last=Vigay | first=Paul |date=2001-08-26 |url=http://www.cropcircleresearch.com/articles/arecibo.html|access-date=2020-12-05|website=Cropcircle Research |location=Hampshire, UK}}</ref>

|access-date=2022-05-13}}</ref><ref>{{Cite web|title=Is the Latest Crop Circle a Message from E.T?|publisher=[[SETI|SETI Institute Online]]|work=General Information |url=http://seti.org/general/ao_message_crop.html|archive-url=https://web.archive.org/web/20041013062350/http://seti.org/general/ao_message_crop.html|archive-date=2004-10-13|access-date=2019-11-18}}</ref> The crop circle is a near replica of the Arecibo message, with the same 23 × 73 grid. Most of the chemical data remains the same, with the exception that in the section detailing important chemical elements, [[Hypothetical types of biochemistry#Silicon biochemistry|silicon]] has been added, and the diagram of DNA has been rewritten. At the bottom, the pictogram of a human is replaced with a [[grey alien|figure with a large, bulbous head]].<ref>{{cite web|url=https://qrius.com/arecibo-message/|last=Chitnavis|first=Urvashi|title=The Arecibo Message: What happened when humanity tried to communicate with aliens|date=2018-03-30|website=Qrius|language=en-GB|access-date=2019-11-18}}</ref><ref name="Griffin2018" /> A solar system with 9 planets is also depicted, with emphasis placed on the 3rd, 4th, and 5th planets of the system. The Arecibo telescope is replaced by a replica of a crop circle that appeared in the same field one year before, and the binary representation of the transmitter's diameter is altered.<ref>Schnabel, Jim (2002-08-08). "Top of the crops 2001". ''Circlemakers''. (''circlemakers.org/totc2001.html'').</ref><ref>{{Cite web|title=The Chilbolton 'Arecibo message' Formation| last=Vigay | first=Paul |date=2001-08-26 |url=http://www.cropcircleresearch.com/articles/arecibo.html|access-date=2020-12-05|website=Cropcircle Research |location=Hampshire, UK}}</ref>

== Computational Analysis ==

== Computational analysis ==

Some researchers have analysed whether the Arecibo signal could be identified as a carrying message by some information theoretic measure that was agnostic in the sense that it does not know the particular shapes of a human or double-helix etc. Presumably such an agnostic measure would be all that any potential ETI could apply to this signal. It is also a useful testbed for humanity's own ability to detect potential extra-terrestrial signals, as we would presumably be similarly agnostic about any shapes particularly special to the broadcasting ETI.

Some researchers have analysed whether the Arecibo signal could be identified as a carrying message by some [[Information theory|information theoretic]] measure that was agnostic in the sense that it does not know the particular shapes of a human or double-helix etc. Presumably such an agnostic measure would be all that any potential ETI could apply to this signal. It is also a useful testbed for humanity's own ability to detect potential extra-terrestrial signals, as we would presumably be similarly agnostic about any shapes particularly special to the broadcasting ETI.

Mahon (2025)<ref>{{Cite journal

Mahon (2025)<ref>{{Cite journal