Where do the aliens live? If an extraterrestrial civilization advanced in its development far enough to use the energy of its galaxy, we could detect the thermal energy emitted as a result of their activity, which is rather difficult to implement in practice.
After researching some promising galaxies from the point of view of the existence of the mind of galaxies, the astronomers came to the conclusion that the probability that the galaxies nearest to us are inhabited by some kind of superdeveloped civilizations is so small.
This news will please those who suffer from xenophobia - fear of creatures that are physically different from us. However, anyone who is looking forward to contact with extraterrestrial civilizations, will be upset that the current level of knowledge of the physics of the Universe does not make it possible to find these civilizations.
Astronomer Michael Garrett from the Netherlands Institute of Radio Astronomy (ASTRON) and Leiden University came to this conclusion after studying radio emissions coming from several hundred galaxies that are promising from the point of view of mind and comparing the obtained data on their infrared radiation. These galaxies were previously selected from 100,000 objects and are distinguished by their “unusually deep” emission in the middle of the infrared region of the spectrum.
But how can the data on radiation in the middle of the infrared spectrum and on radio emission be correlated with the existence of super-developed alien civilizations? All this may indicate that an alien civilization produces heat as a result of its activities. In short, astronomers studied the radiation of galaxies, in which a potential civilization of type III on the Kardeshev scale can potentially exist. The Kardashev scale is a hypothetical measure of the level of heat consumption by a developed alien civilization. For example, a type I civilization is able to use all the available energy of its home planet; a civilization of type II is able to use all the available energy of its star. And finally, a type III civilization has an incredible ability to use the available energy of its galaxy.
For information, the human civilization, according to the level of technical progress, belongs to type 0, and will be able to receive type I status only in 100-200 years (if by that time civilization will continue on Earth in general).
A civilization of type II can use a structure similar to the Dyson sphere, which surrounds its star with a shell or a system of rings, accumulating most of the radiation emitted by this star, and turning it into an energy source for its super-perfect technology. A type III civilization can be described as a race that has mastered interstellar flights, quickly conquered other star systems and created an extensive network of power plants in its entire galaxy.
This may seem like science fiction, but the scale is based on logical conclusions about the growth prospects of a fairly developed civilization in a rather ancient Universe with infinite resources.
So, suppose that somewhere nearby there is a civilization of type III. How can our simplest technologies help discover such a developed civilization? Regardless of which way advanced civilizations reached their level, they still obey the laws of physics, and some galaxies must radiate heat in the middle of the infrared region of the spectrum. The basic physical laws state that energy cannot be created or destroyed, it can only be transformed into other forms of energy. Thus, if our hypothetical type III civilization has spread throughout its entire galaxy, creating an interstellar network around many stars like Dyson's sphere, such structures should glow from the heat they radiate and, therefore, they can be detected by observing radiation in the middle of the infrared .
Applying the experience of the G-HAT team of astronomers from the University of Pennsylvania, USA, studying data obtained using NASA's Wide-Field Infrared Survey Explore (WISE) infrared telescope, Garrett used data from radio observations of galaxies having very bright radiation in the middle part of infrared regions of the spectrum, in the hope of finding out which of these radiations can be explained by natural processes, and which ones are of artificial origin.
The result of Garrett's work is a universal rule called “Correlation between radiation in the middle part of the infrared spectrum and radio waves”, which obey the radiation of the most famous galaxies. In accordance with this rule, if galaxies generate strong radiation in the middle of the infrared region of the spectrum, the source of which is a large amount of star dust in the galactic centers of star formation, they will also be a source of radio emission. In a new article published in the journal Astronomy and Astrophysics, Garrett argued that this correlation is valid for most galaxies that are promising from the point of view of mind existence, therefore the radiation in the middle region of the infrared spectrum is due to the natural processes occurring in these galaxies, rather than the existence of them type III civilization on the Kardashev scale.
“Research by the University of Pennsylvania has already shown that such star systems are very rare, but the new analysis showed that such a statement seems to be very restrained, and in the region of the Universe developed civilization of type III on the Kardashev scale does not exist at all” , - said Garrett in the press release ASTRON. - “In my opinion, this means that at night we can sleep peacefully, because the invasion of aliens is unlikely.”
“Some of these star systems, of course, require further study, but those that have already been studied in detail, as it turned out, have a completely natural nature. There is a high probability that other systems also fall into this category, but just in case it’s worth checking out. ”
These studies are aimed at searching for radiation generated by the most advanced civilizations, and certainly do not exclude the existence of civilizations I and II, as they do not exclude the existence of extraterrestrial life, but, according to Garrett, finding aliens is still very difficult. “The fact that we do not find a civilization of type III is disturbing. Their existence stems from the physical laws that well explain the whole physics of the Universe. We are at too low a level of technical progress. It is possible that developed civilizations are so energy efficient that very little energy is emitted as a result of their vital activity, which we cannot yet achieve. It is important to continue the search for signs of the existence of extraterrestrial intelligence, until we reveal all the secrets of the universe. ” Indeed, astronomers can conduct research based only on the already known laws of the Universe, and use our civilization as an example in order to model a hypothetical alien civilization. But these first studies of galaxies, promising from the point of view of the existence of the mind, show that natural, rather than artificial processes can be a source of radiation in the middle part of the infrared region of the spectrum, so our small corner of intergalactic space still remains uninhabited, at least by superdeveloped extraterrestrial civilizations.