Message to Altair


Message to Altair, officially named CALL to the COSMOS'83, was an interstellar radio message sent from a radio telescope in Stanford, California, USA to the star Altair in 1983. The message was part of a collaboration with Weekly Shonen Jump, commemorating the publication's 15th anniversary.

Transmission

The message consisted of two parts: audio containing messages from children; and a set of 13 images produced by Prof. and Hisashi Hirabayashi. 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 216.
Parts of the images are colour-coded for ease of reading:
  • Black: numbers, text
  • Green: elements
  • Blue: lengths
NumberRecreated ImageExplaination
1Numbers and elements
From top to bottom, left to right:
  • Numbers 1-10
  • 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
  • * H2CO: 6.2 cm
  • * H2O: 1.3 cm
  • * NO: 6.9 mm
  • * HCN: 3.4 mm
  • * CH: 2.6 mm
  • * 3.4 mm × 62 21.1 cm
  • Atomic structure
  • * 8O
  • * 11Na
2Solar SystemMiddle: diagrams 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
3Chemical formulae for DNA compounds
4DNA structure and replication
5Early primitive life
Upper-right: diagram size = 0.5 mm
  • Gives a scale for the physical size of the objects in the diagram
6JellyfishUpper-right: diagram size = 10 cm
Bottom: C + O2 = CO2, representing the process of respiration
7FIsh
Upper-right: diagram size = 50 cm
Middle: H2O, indicating that the fish is in water
8Amphibians
Upper-right: diagram size = 1 m
Middle: O2 × 1 and N2 × 4, representig the rough composition of the Earth's atmosphere
Bottom: H2O
9Lizards or early mammals
Upper-right: diagram size = 1 m
10Apes
Upper-right: diagram size = 2 m
11Humans
Upper-right: diagram size = 2 m
Top:
  • No. of DNA base pairs: ~200 million
  • World population: ~4.3 billion
12Close up of the woman's faceUpper-right: diagram size = 36.4 cm
13Transmission parameters and a toast
Top: total number of bits
Left:
Right:

Search for a response

Altair is approximately 17 light-years away, so the message would have arrived around 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.
In 2023, Shinya Narusawa, who had communicated with Morimoto before his death, asked the Japan Aerospace Exploration Agency 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 22nd. This also fell on the day of the Japanese festival of Tanabata - legend states that it is the only day of the year that deities Orihime and Hikoboshi are allowed to meet each other. Narusawa aims to continue his observations by collaborating with other research institutions.