Posted
on November 16, 2015
What
do you think? Is it a smart idea that humans beamed a message into
space to a large cluster of stars—not knowing who or what, if
anybody, would ever receive the message?
What
sort of aliens might intercept the message? Would they be able to
interpret it? Would they answer?
What
if they are mean and violent aliens, the sort who would love to
discover a yummy, tender new species to gobble up—and a new planet
to plunder? Should we be announcing our presence?
 |
| The Arecibo radio telescope |
On
this date in 1974, humans DID broadcast a complex message to the M13
star cluster. Because it was sent by the Arecibo radio telescope in
Puerto Rico, we call it the Arecibo message.
Now,
don't worry. The M13 cluster is about 25,000 light years away! So,
even if ExtraTerrestrial intelligences do receive the message (and
what are the chances that any E.T.s who live in the region would be
pointing a radio telescope our way just at the right time?), it won't
be for 25,000 years! And if they tried to come visit us, they
wouldn't arrive for tens of thousands of years after that! I think
we're good.
 |
| The M13 cluster |
Not
to mention, there are plenty of planets to plunder with no
technological intelligences to fight off, so it's not likely an
M13-E.T. would be interested in our little, faraway Earth ...Also, we
humans would probably be completely inedible to creatures who evolved
on another planet. Again, I think we're good!
So...why
did we send the message?
If
the possible alien intelligences living on planets in the M13 star
cluster are too far away to chat with...and if it is unlikely in the
extreme, even, that any of them will receive our one-time
broadcast...why did we send it?
The
Arecibo message was a demonstration of the capabilities of the radio
telescope. Also, it was an important thought experiment of what to
look for when we search for messages from intelligent aliens. How can
we communicate with creatures who don't speak any of our Earth
languages, and who may not “speak” at all, with sounds, since
they evolved 100% separately from all forms of Earth life?
The
thing about any aliens who would be intelligent enough and advanced
enough to receive a radio message, they would share something very
important with humans – their science would be based on the same
universal laws and facts as ours. In a way, we would share a language
with every technological alien in the universe: the language of
science.
Check
it out: The scientists who created the message, Dr. Frank Drake and
Carl Sagan (who also earned a PhD but is generally referred to
without the “Dr.” title), chose to code a message as 1,679 binary
digits. “Binary digits” are zeroes and ones, which are useful in
communicating with aliens because zeroes and ones can represent off
and on, or black and white. If you arrange the off/on black/white
bits into a rectangular grid, you can create a picture. As a matter
of fact, we humans do this all the time with our computer graphics!
Even the text on our screens is created by streams of binary digits
that code for pixels...
So,
how would the aliens know what size of rectangular grid to create to
see the picture we were trying to send? That's where the number 1,679
comes in...
You see, that number is semi-prime. That means that, if you multiply the two prime numbers 73 and 23, you get 1,679. Since prime numbers are prime in any base number system, aliens will be able to figure out that they could arrange the on/off pixels in either a grid that is 73 rows by 23 columns or one that is 23 rows by 73 columns. The latter grid produces a jumble, but the 73 rows by 23 columns arrangement produces a picture:
You see, that number is semi-prime. That means that, if you multiply the two prime numbers 73 and 23, you get 1,679. Since prime numbers are prime in any base number system, aliens will be able to figure out that they could arrange the on/off pixels in either a grid that is 73 rows by 23 columns or one that is 23 rows by 73 columns. The latter grid produces a jumble, but the 73 rows by 23 columns arrangement produces a picture:
Note
– the colors were added to help us talk about the various parts of
the message. There is no color information in the original message!
The
top shapes, in white, are a number system that is will be used in the
message, showing the numbers 1 through 10.
The
next shape, which is purple, includes the atomic numbers of the
elements hydrogen, carbon, nitrogen, oxygen, and phosphorus. These
are the elements that make up DNA.
The
green shapes are the formulas for sugars and bases in the nucleotides
of DNA.
The
long white strip in the middle is the number of nucleotides in DNA.
The
blue wavy lines are a picture intended to show the double helix
structure of DNA.
The
red portion is a picture of a human. I wish our heads—and therefore
our brains—looked just a bit bigger!
The
white bit in the middle of the blue line, to the left of the human,
is an indication of the average height of a grown man.
The
white bit to the right of the human is the approximate number of
humans on Earth.
The
yellow shapes are a rough picture of the solar system, with a large
sun, four small inner planets, two enormous and two medium-sized gas
giant planets, and a small outer planet. The planet the message is
coming from is indicated by the fact that it is raised up above the
others.
The
lower purple shape is an outline of the radio telescope.
The
white bits in the middle of the blue line, below the radio telescope,
is the size of the radio telescope's dish.
Questions?
If
you want to read more about the Arecibo message, check out this Wikipedia article.
Did
you know...?
You
can buy t-shirts with the whole Arecibo message imprinted on it...or
just the self-portrait from the message!
Also
on this date:
Plan
ahead:
Check
out my Pinterest boards for:
And
here are my Pinterest boards for:
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