What Happened

In 2001, a crop circle appeared near the Chilbolton Radio Telescope in the United Kingdom that was a near-perfect copy of the original Arecibo signal. However, instead of describing humanity and our Earth, this design describes an alien race and their home planets.

This "answer" has been debunked as a hoax - and it's not hard to see why. The Search for Extraterrestrial Intelligence published a paper on the answer, listing six major problems with the message (some of which will be covered below). As for the article itself, it can be found on the Wayback Machine.

Overview of the Answer

A colored chart of the answer's binary code

To the left is a copy of the Arecibo Answer, complete with color coding that matches the original signal.

If you've read the page breaking down the meaning of the signal, you already know what the different sections represent, but I'm going to cover them - and the changes that have been made - here.

The numbers 1 to 10
The atomic numbers of the elements that make up the alien's genes: Hydrogen, Carbon, Nitrogen, Oxygen, Phosphorus - and Silicon?
The nucleotides in their genes - oddly, Silicon doesn't appear in any of them. This is part of why people think this was a hoax: why include Silicon if it's not used anywhere?
The number of nucleotides in the alien genome (white)
The triple helix structure of alien DNA (blue)
The average height of an alien (blue and white)
A crude image of the big-headed alien (red, obviously)
The current population of... the Earth? (white)
A map of the alien's solar system, highlighting three middle planets (yellow)
An image of broadcasting device, which just happens to resemble a crop circle that was made in the same field a year prior to this design (purple)
The dimensions of the device (blue and white)