Arecibo Message

On 16-11-1974, 45 years ago,the SETI, Search for Extra-Terrestrial Intelligence, sent a message to Messier 13 Globular star cluster, 25000 light years away, hoping that they will get a response.

The “Arecibo Message” was broadcast into space a single time via radio waves from the Arecibo radio telescope in Puerto Rico. 


The message consists of approximately 210 bytes of data.


The message forms the image shown on the right when translated into graphics, characters, and 


The image contains the numbers from 1 to 10, atomic structures of some elements, DNA structures, the solar system, the Arecibo telescope and others.

The message will take 25000 years to send, 25000 years to get a response and the M13 will have moved since we sent the message. So the Arecibo message is viewed as a demonstration of human technological achievement, rather than a real attempt to enter into a conversation with extraterrestrials.

OK, but if a extraterrestrial civilization will get the radio signal, how wi

ll they decode it, go get the actual picture?

So the aliens will find this very strong signal, that comes from a specific point in space. It is a 2380 Mhz signal, but it do

wnshifts 10 Hz at regular intervals.

So you know it’s not coming from a star or a natural object. When you add all this intervals, you will get 1679 intervals. 1679 is a semi-prime number, so it’s a prime number, formed from the multiplication of other 2 prime numbers, 23 and 73.

If the aliens are clever enough, they will know that these downshifts 

are binary code, and they could transform 23 and 73 into binary and put them on a sort of grid. 

They might try 23 columns  and 73 rows, but they will get this:


But if they try 23 rows and 73 columns, they will get the message, that we really wanted to send!

For this day, google made a doodle, so you can check it out on the chrome app!

If you want to check out my post about extraterrestrial life, you can click here!

Take care!