If we do make contact with extraterrestrial intelligence, what happens next? Well, assuming the ball is in our court, the Search for Extra-Terrestrial Intelligence (SETI) project has a plan. In fact, SETI even has a Post-Detection Taskgroup made up of scientists, journalists, philosophers, and, of course, science fiction writers. Astrobiologist Paul Davies of Arizona State University leads the bunch. From Smithsonian:
Their job is to advise relevant parties–other scientists, governments, the United Nations–about what to do if a SETI signal or any "putative evidence of extraterrestrial intelligence" were detected. While waiting for a contact, the group deliberates about what the consequences might be. While a discovery of microscopic life on another body in our solar system would be "of profound significance, which would change our worldview," Davies says, "it's not one of these things that is going to be disruptive to society." But the discovery of a signal from intelligent extraterrestrials could lead to "mayhem." (former of head of NASA's SETI program John) Billingham agrees. "Some people will think that this is a natural event in the continuing work on scientific questions," he says, and others will ask, in panic, "What do we do now?"
People would likely fall into two camps. Catastrophists, as one of the camps is called, might well predict the end of humanity as we know it, or at least the end of our current culture. In 2010 Stephen Hawking said that making contact with aliens would be "a little too risky" and compared the event to Columbus arriving in the New World, "which didn't turn out very well for the Native Americans." But millenarian enthusiasts anticipate revelations of rapture: how to cure cancer, solve the energy crisis or win world peace. And if aliens did manage to come to Earth, says (Center for SETI Research director Jill) Tarter, an admitted enthusiast, "they would likely have outgrown the aggressiveness that has served us so well."