Messaging to Extraterrestrial Intelligence (METI), also called Active Searches for Extraterrestrial Intelligence (Active SETI), refers to the act of using high power communications equipment on Earth to transmit various messages to unknown extraterrestrial intelligences.

METI has been conducted sporadically in the past, but recently a surge of individuals and organizations have initiated or suggested new METI programs, both academic and commercial in nature. METI programs carry unknown and potentially enormous implications and consequences. We feel the decision whether or not to transmit must be based upon a worldwide consensus, and not a decision based upon the wishes of a few individuals with access to powerful communications equipment. We strongly encourage vigorous international debate by a broadly representative body prior to engaging further in this activity. We also note the following:

- ETI’s reaction to a message from Earth cannot presently be known. We know nothing of ETI’s intentions and capabilities, and it is impossible to predict whether ETI will be benign or hostile.

- Because we have just recently (in cosmic terms) attained an interstellar communications capability, it is likely that other communicative civilizations we encounter will be millions of years more advanced than us.

- The Search for Extraterrestrial Intelligence, the scientific effort to determine whether or not other advanced life exists in the universe, is still in its infancy. Even though SETI experiments have been ongoing for more than 50 years, scientists are still decades away from completing a comprehensive search for radio signals similar to those produced by our own technology. As a newly emerging technological species, it is prudent to listen before we shout.

- Although a nearby advanced ETI may have already picked up earth’s omni-directional radio leakage, e.g., early television transmissions, or the presence of industrial wastes in the atmosphere of the earth, such detections are far more difficult than detecting a focused radio or optical signal sent from a large telescope.

- It is not necessary to actually transmit powerful electromagnetic signals in order to study interstellar communication from the perspective of the transmitter, or to develop transmission techniques that might one day be used to respond to a message received from an ETI.

- Opponents of METI would vocally condemn METI transmissions, confusing the public about, and imperiling funding for, bona fide scientific endeavors related to extraterrestrial life.

Intentionally signaling other civilizations in the Milky Way Galaxy raises concerns from all the people of Earth, about both the message and the consequences of contact. A worldwide scientific, political and humanitarian discussion must occur before any message is sent.

Armando Azua-Bustos

George Dyson

Eric J. Korpela

Reinhard Prix

James Benford

William H. Edmondson

Harvey S. Liszt

John D. Rummel

Alan P. Boss

Duncan H. Forgan

Claudio Maccone

Andrew P. V. Siemion

David Brin

John Gertz

Geoffrey W. Marcy

Remington P.S. Stone

Lewis R. Dartnell

Denise L. Herzing

Michael Michaud

Lucianne M. Walkowicz

Paul C.W. Davies

Andrew W. Howard

Elon Musk

Dan Werthimer

Michael M. Davis

Sara Imari Walker

Tim J. O’Brien

Shelley A. Wright