What is an Arecibo message

3.1 Pioneer 10 & 11

  • First or second official, historically documented Terran spacecraft that left our solar system with a "message".
  • Both probes contained a plaque with a schematic representation of the solar system, position of the sun relative to 14 pulsars (identified by their pulse sequence) and the presumed center of the galaxy, sketch of the human anatomy in the correct size ratio to a drawing of the probe, with the right hand of the People raised as a sign of the peaceful intentions of mankind is a representation of a hydrogen molecule and a binary eight. The representations of the probe and the people are drawn to the same scale.
  • have finished their actual mission and are now flying further into the depths of space.
  • The energy supply of the probes, which is based on the decay of plutonium isotope 238, is continuously weaker. While the energy of Pioneer 10 was already exhausted in 1995, that of Pioneer 11 will probably last for a few more years. Until then, sporadic radio contact with the probe, which is now 7 billion kilometers from the sun, will still be possible.

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3.2 Voyager

  • Voyager 1 & 2 were launched in August and September 1977 respectively and were supposed to first explore the outer planets of the solar system. After the successful completion of this mission, the two probes penetrate further into the depths of space.
  • On board each probe there is a gold-plated record that is supposed to convey information from the earth to extraterrestrials. This includes noises as well as images of more or less typical scenes of the earth, but also selected, mostly classical pieces of music, greetings in 55 different languages ​​and schematic drawings that, based on some constant values ​​such as the Planck time, our mathematics, units of measurement, reproduction and to illustrate other things. To what extent these schemes are understandable for extraterrestrials, however, is likely to be questionable.
    A device for playing back the information contained on the disk was included with the probes.
  • Exactly as with Pioneer 10, the energy supply of the Voyager probes is also weaker (here, too, plutonium isotopes were used); the total failure of the systems is expected around 2020.

3.3 SETI

  • SETI (S.search for E.xtraterrestial I.ntelligence) is a project that was founded in 1984 to investigate whether there is intelligent life in the universe.
  • For this purpose, SETI - which has been privately sponsored since its NASA funding ran out in 1994 - used radio telescopes with which it searches selected regions of space for signals that could have been sent by an alien intelligence. So far, however, the project has not been able to announce any success to the public.
  • SETI limits itself to listening to space. The organization does not send its own messages into space because it is of the opinion that humanity is still "too young" to send messages into space yet; Sending messages, she says, is a privilege that older species should have.

3.4 The Arecibo Message / Encounter 2001

  • Instead of SETI, however, there have been several other attempts to send messages into space
  • In 1974, on the occasion of an expansion of the Arecibo telescope in Puerto Rico, the same sent a simple message into space. The message consisted of 1679 bits, which can be put together to form a 73 * 23 or 23 * 73 pixel image, with the latter only showing indistinct noise.
    However, if the message is put together as a 73 * 23 image (from right to left, from top to bottom), you can see (with a little imagination) the Arecibo telescope, our solar system, a section of DNA, a person and recognize other things.
  • In May 1999 another message was sent from a private organization called Encounter 2001, which was sent into space for 2.5 hours on 4 consecutive days. The message was also coded in binary and contained similar content to Arecibo's, only more detailed.
  • Contrary to the representations in some science fiction films and books, the radio and television transmissions emitted from earth into space today will probably never be received in other solar systems because they are so weak that a parabolic antenna is already in one of the neighboring solar systems the size of a continent would be necessary to receive the broadcasts in sufficient quality.