A closer look
If intelligent alien life ever judges our species, it will be based on a 1,679-bit text message that looks like an incredibly sad game of Space Invaders. In 1974, scientists blasted the Arecibo message toward a star cluster 25,000 light-years away. It contains basic math, the human DNA structure, and a highly pixelated stick figure of a human. This ensures that if extraterrestrials do decipher our interstellar greeting, they'll know exactly how biologically fragile we are before they decide to invade.
