{{Short description|1983 interstellar radio message}} {{More citations needed|date=May 2025}} '''Message to Altair''' (Japanese: アルタイルへのメッセージ), officially named '''CALL to the COSMOS'83{{Citation needed|date=April 2025}}''', was an interstellar radio message sent from a radio telescope in Stanford, California, USA to the star Altair in 1983.<ref name="Hirabayashi20142">Hirabayashi Hisashi, "I want to meet aliens! - Astronomers explore the mystery of extraterrestrial life," Gakken Education Publishing (2014)</ref><ref name="Hirabayashi-Miyauchi19872">Hirabayashi Hisashi, Miyauchi Katsusuke, "Message from E.T.: Lectures on the Exploration of Extraterrestrial Civilizations", Asahi Publishing (1987)</ref> The message was part of a collaboration with Weekly Shonen Jump, commemorating the publication's 15th anniversary. right|thumb|200x200px|A recreation of page 11 of the message. It features a drawing of an adult female and male, along with two children.

== Transmission == The message consisted of two parts: audio containing messages from children; and a set of 13 bitmap images produced by astronomers Masaki Morimoto and Hisashi Hirabayashi.<ref name="Hirabayashi-Miyauchi19872" /> The message was transmitted on August 15, 1983 from Stanford, California, USA, with each part being sent over 30 minutes.

The 13 images show numbers, DNA, as well as the evolution of living things from simple organisms to humans. The images in the table below are recreations of the original images sent, which were actually 71 x 71 bits in size. This size was chosen because the product of 71, 71, and 13 is close to the number 2<sup>16</sup>.{{Citation needed|date=April 2025}}

Parts of the images are colour-coded for ease of reading:

* Black: numbers, text * Green: elements * Blue: lengths

{| class="wikitable" |+Images sent in the transmission<ref>{{Cite web |last=NAGAUCHI |first=Yosuke |date=2008-05-12 |title=【科学】届け宇宙人への電子メール 25年前に送信、7年後にも返信来る！？ (1/2ページ) |url=http://sankei.jp.msn.com/culture/academic/080512/acd0805120804006-n1.htm |url-status=dead |archive-url=https://web.archive.org/web/20080517080737/http://sankei.jp.msn.com/culture/academic/080512/acd0805120804006-n1.htm |archive-date=2008-05-17 |access-date=2025-02-18 |website=MSN産経ニュース (MSN Sankei News) |language=ja}}</ref><ref name=":0" /> !Number !Recreated Image !Explaination |- |1 |link=File:Message_to_Altair_01.png|200x200px |'''Numbers and elements''' From top to bottom, left to right: * Numbers 1-12 * Prime numbers * Powers of 3 * Addition * Multiplication * Elements: H, He, C, N, O * Molecules & their wavelengths ** Hydrogen atom: 21.1 cm ** OH: 18.6 cm, 18.0 cm, 18.0 cm, 17.4 cm ** H<sub>2</sub>CO: 6.2 cm ** H<sub>2</sub>O: 1.3 cm ** NO: 6.9 mm ** HCN: 3.4 mm ** CH: 2.6 mm ** 3.4 mm × 62 {{=}} 21.1 cm * Atomic structure ** <sup>8</sup>O ** <sup>11</sup>Na |- |2 |link=File:Message_to_Altair_02.png|200x200px |'''Solar System''' Middle: diagrams (not to scale) of the celestial bodies that make up the Solar System.

* Starts at the top with the Sun * Below the Sun, the planets are shown in order of distance * Some larger moons are shown around their relevant planets

Left: equatorial radii

Right: mean distances from the Sun

Upper-right: R = 10 m |- |3 |link=File:Message_to_Altair_03.png|200x200px |'''Chemical formulae for DNA compounds''' |- |4 |link=File:Message_to_Altair_04.png|200x200px |'''DNA structure and replication''' |- |5 |link=File:Message_to_Altair_05.png|200x200px |'''Early primitive life''' Upper-right: diagram size = 0.5 mm

* Gives a scale for the physical size of the objects in the diagram |- |6 |link=File:Message_to_Altair_06.png|200x200px |'''Jellyfish''' Upper-right: diagram size = 10 cm

Bottom: C + O<sub>2</sub> = CO<sub>2</sub>, representing the process of respiration{{Citation needed|date=April 2025}} |- |7 |link=File:Message_to_Altair_07.png|200x200px |'''FIsh''' Upper-right: diagram size = 50 cm

Middle: H<sub>2</sub>O, indicating that the fish is in water |- |8 |link=File:Message_to_Altair_08.png|200x200px |'''Amphibians''' Upper-right: diagram size = 1 m

Middle: O<sub>2</sub> × 1 and N<sub>2</sub> × 4, representig the rough composition of the Earth's atmosphere

Bottom: H<sub>2</sub>O |- |9 |link=File:Message_to_Altair_09.png|200x200px |'''Lizards or early mammals''' Upper-right: diagram size = 1 m |- |10 |link=File:Message_to_Altair_10.png|200x200px |'''Apes''' Upper-right: diagram size = 2 m |- |11 |link=File:Message_to_Altair_11.png|200x200px |'''Humans''' Upper-right: diagram size = 2 m

Top:

* No. of DNA base pairs: ~200 million * World population: ~4.3 billion |- |12 |link=File:Message_to_Altair_12.png|200x200px |'''Close up of the woman's face''' Upper-right: diagram size = 36.4 cm |- |13 |link=File:Message_to_Altair_13.png|200x200px |'''Transmission parameters and a toast''' Top: total number of bits

Left:

* Transmission wavelength: 70.8 cm * Radio telescope radius: 23.0 m

Right:

* Japanese and English words for toast (as in to raise a toast to someone) * C<sub>2</sub>H<sub>5</sub>OH, the chemical formula for ethanol |}

== Search for a response == Altair is approximately 17 light-years away, so the message would have arrived around the year 2000. Hirabayashi said that while the possibility is not high, if Altair has intelligent life, we could expect a reply from 2017 at the earliest.<ref name=":1">{{Cite web |date=2023-08-10 |title=そろそろ七夕のひこ星から返信がある頃だ...40年前に送信、宇宙人からメッセージ受信計画 兵庫県立大とJAXA |url=https://www.kobe-np.co.jp/news/society/202308/0016684520.shtml |access-date=2025-04-16 |website=神戸新聞NEXT (Kobe Shimbun NEXT) |language=Japanese}}</ref>

In 2023, Shinya Narusawa, who had known Morimoto before his death, asked the Japan Aerospace Exploration Agency (JAXA) for cooperation in looking for any potential reply from Altair. The radio antenna at Usuda Space Observatory observed Altair for an hour at 10 p.m. on August 22, 2023.<ref name=":0">{{Cite web |last=Endo |first=Kazuki |date=August 20, 2023 |title='Anybody there?' Astronomers waiting for a reply from Altair |url=https://www.asahi.com/ajw/articles/14985246 |access-date=February 18, 2025 |website=The Asahi Shimbun}}</ref> This also fell on Tanabata according to old calendar – legend states that it is the only day of the year that deities Orihime and Hikoboshi (represented by Vega and Altair respectively) are allowed to meet each other. Narusawa aims to continue his observations by collaborating with other research institutions.<ref name=":1" />

== References == <references /> {{Interstellar messages}} Category:Interstellar messages Category:Altair Category:1983 in science