This design, which was etched on a plaque attached to each of the two Pioneer spacecraft, was considered pornographic by some (Illustration: NASA)

Click here to see images sent into space on NASA’s twin Voyager probes

For nearly 50 years, the Search for Extraterrestrial Intelligence (SETI) has scanned the heavens with radio telescopes for signs of alien technology. At the same time, scientists have painstakingly crafted messages to send in reply. When NASA launched its Voyager missions in 1977, for example, both spacecraft carried audio recordings depicting the diversity of life and culture on Earth (see gallery).

But never have those messages truly represented all of humanity. On 15 May that will change as the SETI Institute launches a project to collect messages from people around the world. Though there are currently no plans to transmit these messages into space, the project aims to foster a global discussion about whether we should send more than symbolic messages to the stars, and if so, what we should say.

The standard wisdom in interstellar diplomacy is to avoid controversy – a sometimes elusive goal. In the early 1970s, NASA attached plaques to two Pioneer spacecraft etched with basic mathematics, science and line drawings of a man and woman (see image at right). Some complained the space agency was sending “smut into space”, with the naked figures revealing more than they deemed proper for a first encounter.


Other messages have escaped such criticism. One from the Arecibo Observatory in Puerto Rico depicts the human form in so few pixels that its sex is not clear. The Voyager recordings excluded war, poverty and disease.

However, a comprehensive message to the stars should not shrink from the details. Might not an advanced extraterrestrial species, savvy in the ways of intelligent being, notice that something was missing from our description of ourselves? An acknowledgment of our flaws and frailties seems a more honest approach than sending a sanitised, one-sided story. Honesty is a good starting point for a conversation that could last for generations.

If we continue to dodge controversy, we risk sending messages that are both brief and boring. We sometimes clash in our beliefs and customs; we disagree over matters of taste and morality. In no small part this diversity of perspectives is what characterises us as a species. And it may just make us intriguing enough to the inhabitants of other worlds to elicit a reply.

Click here to see images sent into space on NASA’s twin Voyager probes

Douglas Vakoch is director of interstellar message composition at the SETI Institute in Mountain View, California