Where are all the aliens? A new book explores possible answers

image via New Scientist

August 28, 2026, 7:00 PM

• •The article is an interview with astrobiologist Seven Rasmussen about the book Cloudy with a Chance of Starships.
• •Rasmussen explains the Drake equation as a framework that moves from measurable factors such as star formation to highly uncertain ones such as the lifespan of technological civilizations.
• •The discussion distinguishes biosignatures, such as atmospheric methane alongside oxygen, from technosignatures such as artificial chemicals like chlorofluorocarbons.
• •Rasmussen links SETI methods to human technology history through Jill Tarter's idea of a 'cosmic mirror,' noting how radio and laser searches reflect tools developed on Earth.
• •The interview revisits the Fermi paradox as Enrico Fermi's question of why humanity has not seen evidence of extraterrestrial civilizations despite the possibility that they exist.
• •Rasmussen says the Drake equation term they most want to know is the fraction of habitable planets that develop intelligent life, tying that uncertainty to debates over how intelligence is defined on Earth.

Scientific American interviews astrobiologist Seven Rasmussen about the ideas behind the book Cloudy with a Chance of Starships and the modern scientific search for alien life. Rasmussen describes the Drake equation as a way to organize what scientists know and do not know about the prevalence of extraterrestrial civilizations. The conversation explains how researchers look for biosignatures such as atmospheric chemical imbalances and technosignatures such as artificial pollutants or communication signals. It also connects the Fermi paradox and SETI to human assumptions about intelligence, technology and civilization.

Read original article