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Transforming SETI to METI
by Dr. Alexander Zaitsev, IRE (alzaitsev @

Those who propose, or oppose, sending Messages to Extra-Terrestrial Intelligence (METI) must contemplate the Hamlet-like question: "To send or not to send?" The science known as SETI deals with searching for messages from aliens. METI science deals with creation of messages to aliens. Thus, SETI and METI proponents have quite different perspectives. SETI scientists are in a position to address only the local question "does Active SETI make sense?" In other words, would it be reasonable, for SETI success, to transmit with the object of attracting ETI's attention?

In contrast to Active SETI, METI pursues not a local, but a more global purpose - to overcome the Great Silence in the Universe, bringing to our extraterrestrial neighbors the long-expected annunciation "you are not alone!" Thus, it follows that in the context of METI, the answer to the general question of transmissions from Earth requires competence beyond that found within the highly specialized, traditional SETI establishment. We therefore propose that, for solution to the various current METI problems, we consider transforming the familiar SETI search space to a METI search space.

The respected SETI Institute has identified the following 7-dimensional space of unknown quantities for SETI consideration (see, for example: Jill Tarter, 1986. The Cosmic Haystack and Recent US SETI Programs):

  1. Where to search?
  2. When to search?
  3. At what wavelength?
  4. Type of polarization?
  5. Power of radiation received?
  6. How to demodulate the detected signals?
  7. How to decode the received information?

This list can be adapted to aid in decisions regarding transmissions from Earth of our own radio messages to possible extraterrestrial civilizations. Transmission of interstellar radio messages (IRMs) is essentially a new kind of human activity, involving radiation of coherent signals from the Earth into space, addressed to other reasoning beings. Humans have always peered at the sky, in the hope of finding there intelligences beyond our own. METI thus implies a special and purposeful transmission. We can thus replace the terms connected with a search for radio signals, with terms associated with the transmission of same. In a more general treatment, a transformation from SETI to METI can occur as a transition from the science of merely separating those messages that already exist in nature from artificial ones - namely Their reasonable radio signals -- to the art of creating messages that do not exist in nature -- namely our deliberate radio signals directed toward Them.

It would seem that there are two more new measurements in METI-space than there were in the case of SETI. Thus, the METI search space is a 9-dimensional one. We are compelled to consider such questions as "Why is it necessary to transmit and what we shall gain from doing so?" and "Is it dangerous to transmit messages to ETI?". In view of these two additional questions, we suggest that the SETI community (as well as the small but growing METI community) should embrace the following 9-dimensional space of questions for consideration:

  1. Where to transmit?
  2. When to transmit?
  3. At what wavelength?
  4. What polarization to use?
  5. What should be the energy of transmitting radio signal?
  6. What modulation to apply?
  7. What is the optimum structure for transmitted messages?
  8. Why should we transmit interstellar radio messages?
  9. What are the dangers of pursuing METI?

SETI League members should seek answers to all of the above questions. It is important to note that any such answers will be not final, but only preliminary in nature. As we have already emphasized, METI is a new, emerging human activity, and nothing that it implies is yet settled. Therefore, we all have a rare opportunity to join in discussions leading to a wholly new scientific endeavor.

For a more detailed treatment of this issue, please see the article Proposing a METI Institute on the Invitation to ETI website.

Disclaimer: The opinions expressed in editorials are those of the individual authors, and do not necessarily reflect the position of The SETI League, Inc., its Trustees, officers, Advisory Board, members, donors, or commercial sponsors.

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