Director of Berkeley’s SETI Research Center, Andrew Siemion once said: “as we improve our understanding of ancient Earth and the history of our solar system, perhaps we may someday uncover evidence that suggests the activity of another technological civilization right here in our neighborhood.” Massive efforts have been put into the search for alien life in our universe.
For example, in the year of 2015 a research study lead by The Pennsylvania State University astronomer Jason Wright, examined 100,000 neighboring large galaxies and concluded that none of them possessed any obvious symptoms of any highly technologically advanced civilizations. Now, the focus is steered closer to home-- in this past spring of 2017, Wright has proposed that an indigenous technological civilization could have arisen and lived within the solar system before Earth-bound life did.
He also went on to suggest that its “technosignatures” may have potentially survived if they were made of a material that could withstand the weathering techniques of time and erosion and simply remain hidden, awaiting discovery, under the surface of Venus and Mars. Wright also suggests that a potential explosion of life may have occurred around the Cambrian period, when according to fossil records, complex animals first began to emerge. Just like an asteroid wiped out the population of dinosaurs here on Earth, a cosmic catastrophe may have hit this civilization as well, abolishing all the signs of its existence, and forcing its biosphere to “start over” with a small remainder of single-celled-species that had prevailed.
Jason Wright also argues that it is very possible that we have already encountered the technosignatures in geological record, but dismissed them as naturally occurring phenomena. Or, it is possible that the evidence may not even be existent anymore-- erased by the planetary shifting tectonic plates. In his paper, he also concludes that: “the Earth is quite efficient, on cosmic timescales, at destroying evidence of technology on its surface.” Within his cosmic study in 2015, Wright searched for thermodynamic consequences of a galactic-scale colonization, based upon an idea provided by physicist Freeman Dyson in the year of 1960, who argued that a culture with a growing technology would ultimately be limited by access to energy which would drive them to harvest existing energy from their neighboring stars. The study searched for type 3 civilizations-- galactic civilizations that possess the ability to control energy on the scale of its host galaxy-- in an all-sky catalogue from NASA’s Wide-field Infrared Survey Explorer (WISE).
The indicators they searched for were objects that were optically dim but burned bright on the infrared scale which signifies a galaxy filled with heat-emitting, starlight-absorbing Dyson spheres which ultimately signifies the presence of some sort of civilization. After using software to automatically sort through approximately 100 million objects within the catalogue, Roger Griffith, a student of Wright, examined the remaining candidates by hand without success.
James Annis, astrophysicist of the Fermi National Accelerator Laboratory commented on Wright’s research: “Looking for the absence of light as well as the waste heat like Wright and his colleagues have done is really cool. In some sense it doesn’t matter how a galactic civilization gets or uses its power because the second law of thermodynamics makes energy use hard to hide. They could construct Dyson spheres, they could get power from rotating black holes, they could build giant computer networks in the cold outskirts of galaxies and all of that would produce waste heat. Wright’s team went right to the peak of the curve for where you’d expect to see any sort of waste heat, and they’re just not seeing anything obvious. Life, once it becomes spacefaring, looks like it could cross a galaxy in as little as 50 million years. And 50 million years is a very short time compared to the billion-year timescales of planets and galaxies. You would expect life to criss-cross a galaxy many times in the nearly 14 billion years the universe has been around. Maybe spacefaring civilizations are rare and isolated, but it only takes just one to want and be able to modify its galaxy for you to be able to see it. If you look at enough galaxies, you should eventually see something obviously artificial. That’s why it’s so uncomfortable that the more we look, the more natural everything appears.”
Annis suspects that the reason as to why our searches have not found anything yet is because it is possible that fast-gamma-ray bursts were more frequent in the cosmic past and until recently suppressed the rise of advanced civilizations and that as a result, we inhabit “the beginning of history.”
Freeman Dyson also contributed to the conversation saying: “if there are any real aliens, they are likely to behave in ways that we never imagined. The WISE result shows that the aliens did not follow one particular path. That is good to know. But it still leaves a huge variety of other paths open. The failure of one guess does not mean that we should stop looking for aliens.”