On November 16, 1974, scientists beamed a message into outer space from a giant telescope at the Arecibo Observatory in Puerto Rico. For three minutes, the telescope aimed bursts of radio waves toward a cluster of stars more than 25,000 light-years away. A light-year is the distance that light travels in one year: 9.5 trillion kilometers (5.9 trillion miles). This transmission, known as the Arecibo message, was humanity’s first attempt to contact aliens in another solar system.
The Arecibo radio telescope was originally designed to detect signals from space. In 1974, it was upgraded to broadcast information as well—making it the perfect device to send a message to the stars. “Radio waves cut through the cosmic static of interstellar space and travel at the speed of light, making communication as efficient and rapid as possible,” explains Douglas Vakoch. He’s the president of Messaging Extraterrestrial Intelligence (METI) International, an organization that transmits messages to try to communicate with civilizations on other worlds.
The Arecibo transmission carried a simple message written in binary code—a string of 1’s and 0’s that can represent letters, numbers, or other characters. When put together, the code created a series of pictures. They included a human being, a diagram of our solar system, and a strand of the molecule DNA—which holds the blueprint for human life as we know it (see The Arecibo Message: Decoded).
Now, nearly 50 years later, a team of researchers from around the world wants to update the iconic message—and increase its chances of being detected by extraterrestrials.