Philip Morrison

means? What are its problems? And how has our understanding of it evolved over the years gone by? There's a lot to say about the Drake equation, and we'll get there, but first we need some historical context.

Two years prior to the famous Green Bank meeting, astronomers Cocconi and Morrison published an article in Nature suggesting that radio telescopes were now sensitive enough to potentially detect transmissions from alien civilizations.

Seven months later, Drake made the first systematic search for such signals, called Project OSMA, using the 25 meter NRAO telescope at Green Bank, focusing on just two nearby stars.

Despite the small scale of Project OSMA, it was undoubtedly a historic and pioneering experiment.