Humans have yet to encounter any extraterrestrial beings, and, although speculations abound in Hollywood and in science fiction, we really have no idea what contact with aliens would be like. In one scenario, a population of aggressive and malevolent extraterrestrials invade Earth in order to enslave us or eat us as part of their conquest of the galaxy. Still another hypothetical extraterrestrial civilization might welcome us with open arms into peaceful communication and help us solve many of our global problems. With such a wide range of possibilities for an as yet unknown encounter, can we say anything at all regarding the risk of contact with extraterrestrials?

We explore this question in a recently published article titled “Would contact with extraterrestrials benefit or harm humanity? A scenario analysis”. This article was written by Seth Baum, Shawn-Domagal Goldman, and myself and appears in the current issue of Acta Astronautica. Rather than focusing on one particular outcome of alien contact, we take a broad approach of categorizing a wide range of contact scenarios as either beneficial, neutral, or harmful to humanity. In doing so, we draw on scientific as well as ethical analysis to demonstrate that there are a wide range of responses to contact with extraterrestrials, which may depend at least in part on human actions in the near and distant future.

Our television and radio signals have been leaking away from our planet for decades now, detectable by any nearby extraterrestrials willing to listen. The light from our planet, too, shows not only signs of biological life but also signs of rapid warming and climate change. Although we cannot be certain that any of our behaviors will necessarily invoke the wrath–or solicit the aid–of advanced extraterrestrials, perhaps it would behoove us to give thought and care to our future trajectory, just in case someone is watching.