From June 18th to 22nd, the Penn State Extraterrestrial Intelligence Center (PSETI) held the second annual Penn State SETI Symposium. The event saw experts from many fields and backgrounds gathering to discuss the enduring questions about SETI, the technical challenges of looking for technosignatures, its ethical and moral dimensions, and what some of the latest experiments have revealed. Some very interesting presentations examined what will be possible in the near future and the likelihood that we will find evidence of extraterrestrial intelligence.
Among them, there were some very interesting presentations by Adam Frank, Professor of Astrophysics at the University of Rochester; Ph.D. student Matias Suazo, an astrophysicist and member of Project Haephestos at the University of Uppsala; and Nicholas Siegler, the Chief Technologist of NASA’s Exoplanet Exploration Program (ExEP). These presentations addressed ongoing issues in the search for extraterrestrial intelligence (ETI), technosignatures, the role of oxygen in the evolution of complex life, and what motivations extraterrestrial civilizations (ETC) might have for creating noticeable signatures.
How large would an extraterrestrial city have to be for current telescopes to see it? Would it need to be a planet-sized metropolis like Star Wars’ Coruscant? Or could we see an alien equivalent of Earth’s own largest urban areas, like New York City or Tokyo?
A recent preprint by Bhavesh Jaiswal of the Indian Institute of Science suggests that, in fact, we could see cities a mere fraction of that size, using a feature of light known as specular reflection.
How do you power a super advanced alien civilization? Soak up a star. We harness the power of the Sun using solar panels. What if you were to scale this idea to astronomical proportions? Surround an entire star with solar collecting structures or satellites to power your sprawling alien galactic empire. Such massive structures are known as a “megastructures” – in this case a “Dyson Sphere.” We are already trying to detect possible megastructures in space using the dimming of a star and the glow of megastructure components in infrared light. But recent research provides a new detection method – a Dyson Sphere may cause its host star to swell and cool.
This week astronomers announced an unusual transit signal from another star. Although it’s most likely a natural phenomenon, one remote possibility is that this is some kind of alien megastructure. Freeman Dyson and others have considered this idea for decades. Today we’ll talk about the kinds of structures that aliens might want to build.