“The idea behind our research is that, if an entire galaxy had been colonised by an advanced, spacefaring civilization, the energy produced by that civilisation’s technologies would be detectable in mid-infrared wavelengths – exactly the radiation that the Wise satellite was designed to detect for other astronomical purposes, says Jason Wright of Penn State University, the project leader.
Freeman Dyson, the imaginative space theorist, proposed the idea in the 1960s but the technology to put it to the test has only recently become available. “Whether an advanced spacefaring civilization uses the large amounts of energy from its galaxy’s stars to power computers, space flight, communication or something we can’t yet imagine, fundamental thermodynamics tells us that this energy must be radiated away as heat in the mid-infrared wavelengths,” Wright says.
Astronomy column in FT Weekend Magazine, May 2nd, 2015
A neat idea: any galaxy home to energy-guzzlers like us, but on a far bigger scale, will be lit up like a Christmas tree, glowing with surplus infrared. The survey hasn’t found any yet, among 100,000 galaxies examined, but 50 or so do have “unusually high levels of infrared radiation, suggesting possible conversion of some stellar radiation to power alien technology”.
Reminiscent of James Lovelock’s insight, also during the 1960s, that the obvious way for NASA to scan for life on Mars would be simple analysis, by infrared spectrometer, of the chemical composition of that planet’s atmosphere. The presence of methane, oxygen and nitrogen in dynamic abundance would betray the activity of living organisms regulating the atmosphere as a source of raw materials and a sink for gaseous waste. As it turned out, infrared analysis revealed the Martian atmosphere to be almost entirely composed of carbon dioxide, and close to chemical equilibrium, and Lovelock therefore concluded the planet was probably lifeless.