can you say that again?"...not a snappy telephone
conversation (and not in perfect English, no matter how hard Star
Trek tries to convince us it would be that easy). The chances are
our nearest cosmic neighbours might be hundreds of light years away,
taking four or more human lifetimes for any chance of success.
Deliberate message sending needs to be done over generations
unlike the one sent from the world's largest radio telescope at
Arecibo in Puerto Rico, by Dr Frank Drake in 1974. The chances of
any message being picked up from a one-off transmission are
vanishingly small. But Drake had good reason to signal the stars in
this way - it was a celebration of the upgrade of the
telescope rather than any serious effort to make contact with
ET.
It was a hot tropical afternoon and 250 dignatories had gathered
at the telescope to celebrate the three years of hard work that
would allow the 1,000 foot giant to peer further into the
universe.
Drake, now President of the SETI Institute in California, had
devised a message with the help of some postgraduate students. Over
169 seconds it sang a song of Earth to the stars with a power than
outshone the sun on its particular frequency. "That ought to get
someone's attention, I thought", said Drake later in his book "Is
Anyone Out There?"
For dramatic effect, the sound of the message was broadcast to
the assembled audience while it was being transmitted. Drake wrote:
"The two pitched tones of the message filled the air, like the
trilling of a strange musical theme played on a giant electronic
synthesizer. The song, unique and full of yearning, affected us
strongly.
"...I saw women in sleeveless dresses rub chills from their arms.
I saw the eyes of sober scientists filled with tears. And mine did
too."
The message is simple. Reading from the top it gives the numbers
one to ten, describes the biochemistry of life (green), the
complexity of DNA (blue and buff), a human (red) with the height to
one side and the population of Earth to the other, the sun and nine
planets (in yellow) shows one planet raised beneath the human's feet
to indicate that is the inhabited planet and below that information
about the Arecibo telescope where the message orginated. It was
transmitted as a string of zeros and ones (binary) and aimed at the
Hercules cluster of suns some 25,000 light years away. If anyone is
out there we'll know...in 50,000 years.
There have been some other attempts to announce our presence to
the universe, but it'll be several hundred thousand years before any
of the four spacecraft reach a star system. In
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