Sydney - Sep 29, 2002
While some scientists cautiously plan for ways to reply to extraterrestrial transmissions, others haven't waited for a signal to start talking. Sending messages from Earth into space to announce the existence of the human race is somewhat rare and controversial. Digital transmissions have been beamed into space from radio telescopes, and four spacecraft currently leaving the solar system bear messages for anyone who finds them.
The official position of the SETI Institute in the USA, and many other astronomers working in SETI, is to remain silent and passively listen for signals. But as message designer Dr Douglas Vakoch noted in his earlier interview with SpaceDaily (Doug Vakoch's And Lands Beyond Beyond, August 23 2002), this policy is not legally binding on anyone.
Russia's Professor Alexander Zaitsev is one astronomer with a different perspective. He has implemented his own message transmissions from one of the world's most powerful deep space transmitters, and has even coordinated a message transmission project known as TAM (Teen Age Message) with Russian students.
Professor Zaitsev's team used an approach to message composition that's strongly reminiscent of the classic 1974 Arecibo transmission, where a digital signal was designed to be reassembled into a low-resolution picture that included a DNA molecule, the solar system and a human figure. Two scientists developed a 23-page pictorial message that was broadcast to four stars in 1999.
A different approach was taken with the TAM project in 2001, which included music performed on a theremin electronic instrument (best known for its appearance in the Beach Boys song "Good Vibrations".) The teenage scientists also included simple digital pictograms depicting people and natural scenes.
Professor Zaitsev discussed his opinions in an email exchange with the Australian correspondent Dr Morris Jones.
Q:The SETI Institute in California has a policy of waiting for a Signal before replying. You have transmitted before any signal from extraterrestrials has been received. What do you think of the policies of the SETI Institute?
A:In my first METI publication (METI is short for Message for ETIs) I put the question: If everybody in the Universe is so wise as we terrestrials, and prefers a listen-only strategy, are extraterrestrials really so sensible? Nobody would transmit at all. Perhaps the explanation of the Fermi Paradox ("If aliens exist, why have we never contacted them?") is that throughout the Universe this non-altruistic receiving point of view prevails.
I think that the SETI Institute policy is not a scientific viewpoint, but a "sectarian" position.
Q:How do you select the target stars for your transmissions?
A:It is very interesting process. During the TAM (student message) preparation Russian students made very careful selections among nearby stars. They took into account their age, spectral type and the possible presence of planets. The also considered the presence of any remarkable radio astronomical objects near our own Sun if it were viewed from the perspective of the target star. This allowed for the possibility that extraterrestrials could discover our message accidentally during observations of any interesting nearby natural radio sources.
Q:How do you physically encode the messages? Do you prefer any specific frequencies or forms of modulation of the signal?
A:The transmission source is the 70 m dish and transmitter of the Evpatoria Planetary Radar (EPR), the most powerful radar of its kind outside the USA. Only the radars in Arecibo, Puerto Rico and Goldstone, California are more powerful than ours. The frequency band of EPR is 5 GHz, with a wavelength of 6 cm. This is one third of a wavelength of 18 cm, which corresponds to an OH (Oxygen/Hydrogen ion) spectral line.
I believe that frequency modulation (as carried out in FM radio transmissions) is the most preferable form of modulation for analog Messages, and frequency manipulation (changing the frequency used for the signal) for digital messages.
Q:If a signal from an extraterrestrial source were received tomorrow, would you reply? What sort of a message would you transmit?
A:First of all, I would send a "mirror" transmission, which would re-transmit the received extraterrestrial signal. Afterwards, I would try to answer any questions they sent if we were able to decode their message. If we were unable to decode their own message, I would send my own message and ask the extraterrestrials to wait a little until we decode theirs and answer their questions.
Q:Doug Vakoch of the SETI Institute suggests that it could take so long for extraterrestrials to reply to a message that homo sapiens could no longer exist by the time we receive a reply. Yet you have sent questions for extraterrestrials to answer in one of your messages. How long would you expect to wait to receive a reply?
A:There are millions of people who know the size of the universe and the speed of light. People can draw conclusions from this. To me, the main goal of our messaging is to bring to extraterrestrials the long-expected message that "You are not alone!". And if everybody in the Universe would follow this moral goal, than is a hope that someday we shall get a message, too. It will not be a reply from our proposed correspondent, but from some other one.
Q:Why do you think we have not received a message from extraterrestrials so far?
A:I do not think that this is necessarily so. For example, it is possible that the far side of the moon already has a message, which extraterrestrials stored for us many years ago.
Q:Most SETI researchers expect that any extraterrestrial civilisations we detect will be much older, and more advanced, than homo sapiens. Do you agree?
A:I can only speak definitely about ourselves on Earth. But I am sure that we have things that are worth communicating to other civilisations. It would be very interesting for them to hear from us, undoubtedly.
Q:Do you think it is likely that any messages placed on board spacecraft(such as the Voyager records) will ever be retrieved by extraterrestrials?
A:I hope so! But whatever the case, the composition of such messages provide very interesting lessons for us.
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Doug Vakoch's And Lands Beyond Beyond
Sydney - Aug 23, 2002
So far, humanity's efforts to communicate with extraterrestrials have mostly resembled the way people treat the media. Everybody listens to a certain degree, but very few people talk back.
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