code for the height of humans. Because we cannot communicate in 'human' measurements (such as feet and inches) the height is represented in 'wavelength units'. As mentioned earlier, the actual message was transmitted on 2380MHz. To convert this into a wavelength we divide into 300, to obtain a wavelength in metres. 300/2380 = 0.12605042m = 12.6cm. This is our 'wavelength unit'. From the code for the height of a human, we can see that the value is 1110 in binary, or 14 in decimal. If we multiply 14 by our wavelength unit (12.6) we get 176.4cm, or roughly 5'9" - the average height of humans. The next section is a simplified representation of our Solar System - where we live. It shows the sun and nine planets, roughly representative of size. By moving the third planet up slightly it highlights that something is significant about the third planet from the sun - Earth. The last section depicts the origin of the message itself - the Arecibo radio telescope, which is the curved structure. Underneath this, as the last two lines of the message, is another binary number. This time it's 100101111110 (split onto two lines in the centre) and equates to 2430 in decimal. Again, using our universal 'wavelength units' we get 2430*12.6cm which is 30618cm - or approx 1000', the diameter of the Arecibo radio dish. Differences between the message sent in 1974 and the one received in 2001 (Left: what we sent in 1974 / Right: what we