Earth's first message for extraterrestrials is sent into space - November 16th, 1974

On this day in 1974, scientists at the Arecibo Observatory in Puerto Rico sent the first message intended for alien lifeforms. 

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Episode Transcript

Speaker 1 (00:00):
This Day in History Class is a production of I
Heart Radio. Hello and welcome to This Day in History Class,
a show that decodes history one day at a time.
I'm Gabe Lousier, and today we're looking at humanity's first
earnest attempt to get in touch with an alien. The

(00:28):
day was November sixteen, seventy four. Scientists at the r
CEBO Observatory in Puerto Rico sent the first message intended
for alien life forms. The broadcast was part of a
ceremony held to mark the completion of a major upgrade
to the observatory's radio telescope. Early that afternoon, the observatory's

(00:51):
powerful one million watt transmitter beamed the message into outer space.
The so called r CEBO message was written in binary code,
and when translated, it formed a series of symbolic pictures
that expressed key information about the human species. Although the
planet Earth has been haphazardly emitting radio signals since the

(01:13):
late nineteen thirties, the r c BO message was the
first deliberate transmission to extraterrestrials. It was mostly intended as
a symbolic act, a way to show off the considerable
power of the newly installed transmitter and the extensive range
of the telescope's dish antenna. However, many people, including those

(01:35):
who wrote the message, treated it as a sincere attempt
at first contact. Others took the message seriously as well,
but advised against sending it since there was no way
of knowing who might receive it or whether or not
they'd be friendly. The contents and format of the message
was developed by Frank Drake, a professor of astronomy at

(01:55):
Cornell University, with input from other scientists including Richard Isa Kman,
Linda May, and James C. G. Walker. Drake and his
team had a difficult task ahead of them. Not only
did they have to decide what to say to any
potential aliens who might be listening, they had to figure
out how to say it in a way they would understand.

(02:16):
Spoken languages were ruled out right away, as there was
little chance of an alien civilization knowing any of them.
Numbers and equations seemed a bit more promising, math being
the language of the universe, and all but the symbols
we used to express numbers are strictly a human invention.
The arbitrary nature of words led Drake to consider a

(02:38):
more universal medium pictures. He and the other researchers created
what's known as a bit map, a pixelated image where
each part corresponds to a different string of binary numbers.
You can think of it kind of like a paint
by numbers kit. The message was transmitted as a string
of ones and zeros, with each of the ones representing

(02:59):
a shaded square on a grid and each of the
zeros representing an unshaded square. So in order to decode
the message, the recipient has to organize that string of
numbers into a grid and then fill in the correct
squares to see the picture. If that's done correctly, then
you have a symbolic image twenty three rows wide and
seventy three rows long picture the graphics from an old

(03:22):
Atari game like Space Invaders, and you're not far off.
So assuming an alien could decode the message, what exactly
would they see, Well, Drake and his team wanted to
include basic information about the human species and what we
know about the universe, but of course they were constrained
by what they could easily depict through shaded squares and

(03:44):
empty spaces. They eventually settled on including the numbers one
to ten, the atomic numbers for common chemical elements like
hydrogen and carbon, a representation of the double helix structure
of human DNA, A map of our solar system and
looting Earth's position, a drawing of the r c BO
radio telescope, the number of people on Earth four billion

(04:06):
at the time, and last, but not least, a stick
figure drawing of a human being. Admittedly, there was still
some doubt as to whether an alien civilization would be
able to decode and interpret the message. Drake decided to
test the translatability of the message by sending it to
his friend and colleague, astronomer and author Carl Sagan. Sagan

(04:30):
had no knowledge of what the message contained, but was
able to quickly determine nearly all of its contents. The
one exception was the chemistry section, but that was only
because Sagan didn't know much about the subject. Drake also
sent the message to some biochemists he knew, and they
had no trouble at all decoding that part. So Frank

(04:50):
Drake and his team moved forward with the project, satisfied
that their message could be understood by any aliens, at
least as intelligent as Carl Sagan. The next up was
to choose a destination, a point somewhere out in deep
space to transmit their message to. After an extensive review
of star charts, Drake decided to beam the signal in

(05:11):
the direction of M thirteen, otherwise known as the Great
Cluster in Hercules, that collection of more than three hundred
thousand stars and potentially just as many planets orbits the
center of the Milky Way galaxy, roughly twenty five thousand
light years from Earth. The clusters immense size provides plenty

(05:32):
of opportunities for the message to be received by any
life forms who might be tucked away out there. But
more important than its size was its location. The center
of M thirteen was set to be directly within the
telescope's beam during the designated time of the ceremony. The
transmission of the r CBO message began at one pm

(05:54):
on November sixteenth, nineteen seventy four. It consisted of one thousand,
six hundred seventy nine bits of information, which took about
three minutes to send. The method used was similar to
how a dial up computer modem sends binary code over
a phone line, and just like in that process, you
could audibly hear the message being sent thankfully, it was

(06:17):
much less annoying than a noisy modem. In fact, Frank
Drake thought it sounded like bird warbling. Take a listen
and decide for yourself. At the time of recording, it's

(06:38):
been just forty eight years since the r C Bow
message was broadcast. In that time, moving at the speed
of light, the message has traveled less than three hundred
trillion miles, a tiny fraction of the distance still left
to go. In other words, it'll be a very long
time before the message actually reaches its destination, about thousand

(07:00):
years in fact. Once it does arrive, who knows if
anyone will be there to receive it, and if they are,
whether they'll be able to decipher it. The good news
is that either way, the message will keep right on going,
and millions of years from now it'll reach distant galaxies
where it will have all new opportunities to make contact

(07:20):
with whatever might be living there. But even if no
one ever replies, it's still kind of comforting to know
that some marker of our species will still be bouncing
around out there, trying to introduce itself for all eternity.
I like to imagine that EON's from now, some highly
developed species will find the r c EBO message and
solve it as easily as a crossword puzzle. Then they'll

(07:44):
smile with their four interior mouths and stick the drawing
to their quantum refrigerator. A weird little eight bit postcard
from those dummies on Earth. I'm gay, Bluesier, and hopefully
you now know a little more about history today than
you did yesterday. You can learn even more about history

(08:04):
and see the r CBO message for yourself by following
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at t d I h C Show. You can also
rate and review the show on Apple Podcasts, or you
can get in touch with me directly by writing to
this Day at ihart media dot com. Thanks as always
the channeler Mays for producing the show, and thanks to

(08:27):
you for listening. I'll see you back here again tomorrow
for another day in history class