its a message sent into space from the arecibo radio telescope in 1974. Carl Sagan and Frank Drake composed it. its actually a binary message but this ones in colour so you can see the different parts. at the top its numbers 1 - 10 then atomic numers of some of the elements, dna double helix, what man looks like, our solar sytstem, and a represenatation of the arecibo transmitter. its made of 1679 binary digits which is a semiprime number. i think they chose that because it would be presumably easiest to decipher that way if you used a rectangle.
