Every civilization in the Universe eventually runs out of energy on its home planet and once this happens they will build a massive collector of starlight, a shell of solar panels to surround their home star. Astronomers call the possible structure as Dyson Spheres. This famous theory was formulated by mathematician-physicist Freeman Dyson in 1960. Astronomers believe that Dyson theory is a thought experiment but not completely rejected it. If the hypothesis is true, then, one way to find advanced alien civilizations is to look for signs of Dyson Spheres.
Last September 2012 three astronomers, led by Jason Wright, started a search for Dyson Spheres that would span for two years. The project will cross the Milky Way, along with other galaxies estimated to be millions. Their project already got support from the Templeton Foundation, an organization that would like to fund research on humanity’s big questions such as human purpose and ultimate truth.
Theories about advanced aliens are somewhat not scientific but the search for intelligent alien beings has been dependent on such theories. The Search for Extraterrestrial Intelligence (SETI) has been scanning alien radio communications using telescope arrays. As of today, humans do not have the excess technology that SETI has been looking in the heavens. Robert Gray said that in order to pick up a radio signal from light years away an enormous amount of energy is needed which can only be produced by thousands of big power plants. SETI is expecting that advanced civilizations have interest in communicating other civilizations, or at least have enough energy expenditures. SETI also assumes that extraterrestrial civilizations will communicate through radio signals. Therefore, to find intelligent aliens, it is not enough that they only exist; they should have technology that is predictable by humans in many ways.
The search of Dyson Spheres is a little less on the goals of futuristic alien civilizations when compared with SETI. Most assumptions of Dyson Spheres search are directly related to simple biology. Wright explained that life has energy that reradiate as waste heat. Therefore, more energy is present in larger civilization. This larger civilization reradiates more heat.
Life also reproduces, which could lead to the increase in demand of energy. If the increase continues, life will absorb all the available energy in a certain planet. The possible situation could force the growing civilization to get energy from other planets and their stars.
To fully understand the Dyson Sphere, it is wise to let the Earth as a test case. Oliver Morton pointed out that the sun is supplying 120,000 terawatts daily into Earth. The amount of energy that the sun supplies to Earth is equivalent to 10,000 times of the amount of energy in humanity’s industrial civilization. However, it is important to note that mankind’s industrial civilization is young and tremendously increasing. For the past 30 years, global energy is doubled. Using this trend, mankind will be having the same amount of energy that the sun supplies in 400 years. When that time comes, making plan for a Dyson Sphere is likely one of the options.
It is logical to assume that intelligent or advanced alien civilizations have more energy than humans because they may have started billions of years ago. Dyson Spheres may have also started millennia ago in the universe.
Dyson Spheres also consistent with Kardashev Scale, another theory of civilizational advancement. Soviet astronomer Nikolai Kardeshev made a technological advancement theory in 1964. It is based on mastery of civilization of larger and larger energy sources over time. Kardashev Scale has three types of civilizations. Type 1 civilization utilizes all available energy on its home planet, type 2 utilizes all available energy from its local star, and type 3 civilization uses all energy in its galaxy. Dyson Spheres search is logically a search for Type 2 civilizations. It may have an advantage over SETI’s effort in finding intelligent alien because of its premise on energy usage of extraterrestrial civilizations. It allows researchers to find aliens that are not necessarily interested in communicating with other civilizations.
The existence of Dyson Spheres would give off a heat signature that can be seen through mankind’s infrared telescopes. Dyson Sphere would be heated by the solar energy it collected, similar to a computer that would heat up when it utilizes electricity. That heat would then radiate off the sphere as infrared light. Wright explained that Dyson Sphere would appear brightly in the mid-infrared. Similar to human body that is not visible in the dark, but brightly shines in mid-infrared goggles.
A civilization capable to develop a Dyson Sphere would have to do everything that it would not be detectable. Wright said that to hide a Dyson Sphere, it would require big amount of engineering across the whole civilization. That particular civilization would build massive radiators that give off heat that would be undetectable against the cosmic microwave background.
The project by Wright to search for Dyson Spheres is not the first one. Fermilab researchers did the same research in the 1980’s and they initially found candidate sources. However, on closer look, they discovered that those candidate sources were giant stars or dusty objects that absorb starlight and then reradiate it.
Wright and his team will get access to data not yet accessible to Fermilab’s researchers. They will be scanning 3 different infrared sky surveys which include Wide-field Infrared Survey Explorer (WISE) of NASA which is way more sensitive than IRAS, about hundreds of times. They will be searching galaxies that may have a large number of stars surrounded in technological complex structures.
If Wright and his team find something not normal, a long process for confirmation will immediately start. A process that likely needs telescopes and astronomers around the world. Wright said that they will not conclude right away without further examinations from experts. He mentioned that many times there were strange objects discovered in the past only to discover that they are natural phenomenon after thorough investigations. Nikolai Kardashev thought at first that he discovered great candidates for Type 3 civilizations but later knew that they were quasars.