Writing in Acta Astronautica, Shostak says that the odds favour detecting such alien AI rather than “biological” life. Seti researchers have long argued that nature may have solved the problem of life using different designs or chemicals, suggesting extraterrestrials would not only not look like us, but that they will not be carbon based life forms, but be bound to follow “at least some rules of biochemistry, live for a finite period of time, procreate, and above all be subject to the processes of evolution.”

“If you look at the timescales for the development of technology, at some point you invent radio and then you go on the air and then we have a chance of finding you,” he told BBC News.“But within a few hundred years of inventing radio – at least if we’re any example – you invent thinking machines; we’re probably going to do that in this century. So you’ve invented your successors and only for a few hundred years are you… a ‘biological’ intelligence.”

From a probability point of view, if AI-powered machines evolved, we would be more likely to spot signals from them than from the “biological” life that invented them.

“But having now looked for signals for 50 years, Seti is going through a process of realizing the way our technology is advancing is probably a good indicator of how other civilisations – if they’re out there – would’ve progressed. Certainly what we’re looking at out there is an evolutionary moving target.”

Dr Shostak says that artificially intelligent alien life would be likely to migrate to places where both matter and energy – the only things he says would be of interest to the machines – would be in plentiful supply. That means the Seti hunt may need to focus its attentions near hot, young stars or even near the centers of galaxies.

“I think we could spend at least a few percent of our time… looking in the directions that are maybe not the most attractive in terms of biological intelligence but maybe where sentient machines are hanging out.” Shostak thinks SETI ought to consider expanding its search to the energy- and matter-rich neighborhoods of hot stars, black holes and neutron stars.

Data centers like this generate a lot of heat, and keeping them cool is a major challenge for modern computing. Intelligent computers would likely seek out a low-temperature habitat. Bok globules (image at top of page) are another search target for sentient machines. These dense regions of dust and gas are notorious for producing multiple-star systems. At around negative 441 degrees Fahrenheit, they are about 160 degrees F colder than most of interstellar space.

This climate could be a major draw because thermodynamics implies that machinery will be more efficient in cool regions that can function as a large “heat sink”. A Bok globule’s super-cooled environment might represent the Goldilocks Zone for the AI powered machines, says Shostak. But because black holes and Bok globules are not hospitable to life as we know it, they are not on SETI’s prime target list.

“Machines have different needs,” he says. “They have no obvious limits to the length of their existence, and consequently could easily dominate the intelligence of the cosmos. In particular, since they can evolve on timescales far, far shorter than biological evolution, it could very well be that the first machines on the scene thoroughly dominate the intelligence in the galaxy. It’s a “winner take all” scenario.”

“Alien Electromagnetic Signals Will Be Discovered by 2040” –SETI’s Chief Astronomer