It's been just over a half-century since our first deliberate, designed transmission to the stars beamed its way into cosmic history. Dubbed the Arecibo message after the sprawling radio-astronomy facility that sent it skywards in November of 1974, the transmission was a "selfie" of sorts (albeit one for all of collective humanity), containing information about our planet, our solar system, and even the basic molecular structure of our DNA. Its primary designer and proponent was Frank Drake, an astronomer already famed at the time as a key figure behind SETI, the Search for Extraterrestrial Intelligence.
One motive for the message was to demonstrate that SETI's quest for radio signals from talkative aliens was reasonable. Directed at the globular cluster M13 some 25,000 light-years away, the three-minute transmission briefly shined ten million times brighter than our sun—a potent testimony to the feasibility of interstellar communications. If we could do such things using our relatively crude equipment, Drake mused, then surely other advanced technological cultures somewhere out there could do it too, and much more, bolstering the case for more robust SETI efforts. Then again, even if cosmic civilizations are a dime a dozen in the Milky Way, if they all stay quiet then SETI should be doomed to failure; beaming out a message of our own was an exercise in cosmic optimism.
Fifty years on, the silence from the skies is deafening. No SETI project has delivered any whisper of first contact, and the great radio dish that sent Drake's message toward M13 has collapsed into obsolescence. But the deeper meaning and importance of the effort endures—just as the transmission itself does, still streaming at light-speed through the void to its distant target. To commemorate the anniversary, Drake's daughter, the science journalist Nadia Drake, reflects on his message's legacy and presents new glimpses of its origins in an exclusive piece for Scientific American. --Lee Billings
