Find life is perhaps the main and most desired goal of astronomy, preferably intelligent, to somewhere beyond Earth. Given the ease with which life spreads and multiplies on our home planet, and the presence of ingredients for life everywhere in the Universe, it is difficult to conclude that we are alone in the Universe. In the milky Way galaxy of 400 billion stars, each with its own unique history and chances of the emergence of life. Despite how technologically advanced people become, the search for extraterrestrial civilizations are to no avail, maybe because technologically developed civilization do not communicate the way we are accustomed. But a sufficiently advanced civilization could build a sphere around its sun — a Dyson sphere — to absorb 100% of its energy. Incredibly, we have the technology to detect them. Of course, if they exist.
Roy Dyson, viewed as a step on the way to the Dyson sphere when the light is blocked by a series of spacecraft, flying in front of the star.
On Earth the amount of energy available to us is determined by the amount of sunlight falling on the surface of our planet. The distance of the Earth from the Sun is roughly equivalent to 1300 watts per square meter, but drops to 1000, if the light is forced to pass through the atmosphere. If we covered the space above the Earth’s atmosphere by the solar panels, we would collect 166 million gigawatts of energy, constantly, throughout the Land. This is a huge amount of energy: even a second, such a flow could provide earthlings with energy for the whole year. But only part of this energy produced by the Sun. There are other ways.
The concept of space solar power has a long history but no one dared to even think about the array of billions of kilometers. Sphere or Dyson swarm would go even further, by surrounding or wrapping the panels the Sun itself.
For example, we could build a swarm in space to collect even more solar energy. Imagine a fleet of spaceships that move in a ring or series of rings with a large collection area. This energy could be used for any purpose: it could be sent to Earth in a beam, could be used in place to create a network throughout the Solar system, or for interplanetary or interstellar communications. That’s where the idea of megastruktur aliens which have been proposed as one explanation for the phenomenon of darkening of the star Tabby.
However, the most ambitious of the so-called megastructure is a Dyson sphere: a shell around the star, which absorbs all her energy. We could do it [a small planet like mercury, convert it into iron and oxygen and to create the reflective surface of the hematite. If an alien civilization did the same, the shell will completely cover the star, making it virtually undetectable.
The Dyson sphere will completely cover the star, absorbing its ultraviolet and visible radiation. Will pass only infrared radiation and long waves.
In any case, undetectable to telescopes operating in the visible light spectrum, because this area completely blocked the light of stars. But even a highly reflective surface should absorb some of the energy. But if energy is absorbed over time, it needs somewhere to redirect to maintain a stable temperature. Therefore, the energy must go out into the Universe, even if no visible light will not. As the Earth at night emits energy in the infrared, and the Dyson sphere will be.
At night, the Earth radiates electromagnetic signals, but the majority of them is in the infrared range, because the space is sent to the sunlight and heat absorbed during the day.
The European space Agency recently released a huge data set with the most powerful satellite ever charted and explored the stars of the milky Way: Gaia. He was able to gather information about 1,7 billion stars in our galaxy, allowing us to create the most complicated 3D map of stars in the milky Way. It’s not all stars, but an order of magnitude more than there were before.
One of the great things that were able to measure Gaia, was the color and the size of many stars, dim red dwarfs (and brown dwarfs) to stars remains like white dwarfs, main sequence stars, giants and supergiants, which Shine all the brighter. But Gaia is observed not only in the visible but in the near-infrared spectra, and thus saw the objects that are hidden from the eyes of people. Among them cryogens stars as giants and dwarfs. And Dyson spheres, if they exist and have certain profiles of temperature/luminosity.
A big, fat line that crosses the diagram from the lower left to the upper right corner, is the sequence in which the stars are synthesizing hydrogen into helium. Top right are stars in the giant or supergiant phase: they burn heavier elements and expand to much larger sizes. Even though they glow brighter, their temperature is lower because the energy is dissipated over a large area, emitting energy.
The Dyson sphere does the same thing, but with normal or low-mass star. You are creating a large surface area with which to escape the star’s energy, and it radiates at a lower temperature, thus giving the same total energy. An infrared signature is supposed to give us a similar field, but the satellite Gaia suggested another option: Eric Zachrisson: the mismatch distance based on luminosity, with the distance of the parallax.
The method of parallax used 1800 years, involves observing changes in the position of the stars, which is adjacent to a more distant background star. If the distances on the parallax and the luminosity of the star does not match, this may explain the megastructure aliens… or that the star is in a binary system.
When you conclude about the distance based on the observed light, and then perform measurements in a completely different manner (by using geometry), two numbers must match. The fact that Gaia saw a few differences, can talk about different things, including the structures of the aliens. Human nature is such that we are looking for immediately the most fantastic explanation. But the more down to earth and reasonable reason will be the existence of double stars companions: this is a fairly common phenomenon in the Universe. The lack of excess infrared radiation, is needed for structures like a Dyson sphere, leads us away from the hypothesis of aliens and their structures.
A number of observatories, including spacecraft, Gaia, possess the technology, which in principle is able to detect the Dyson sphere, located a few thousand light-years from Earth, assuming they are the same distance from a star like the Sun as Earth from our sun. Red dwarf star should be visible in the eyes of Gaia with a small Dyson sphere at a distance of hundreds of light-years, but a giant or supergiant star will be visible from almost anywhere in the galaxy. Among 1.7 billion of objects collected by Gaia, it would be possible to find the Dyson sphere in the process of construction. And comparing the data via infrared observatories, it would be possible to find ready-made Dyson sphere that radiate enough energy. At the time of publication of this article, however, in the milky Way had no sphere of Dyson.
But this does not mean that they are not; this means that, if they are, we have not yet seen. Dyson spheres can be further than the Gaia, being located near the stars smaller. Infrared Observatory like WISE define the boundaries of the search and the observatories of the next generation have the potential to detect the signature of the dissipation of heat from such a facility.
Given the complete set of observatories, which surveyed the sky is relatively safe to say that we haven’t found any Dyson spheres at the present time. Perhaps somewhere there are intelligent aliens, using all the energy of your whole and creates a huge transplanetary Empire, but the evidence is zero. To only one reasonable conclusion: our galaxy, as far as we can tell, does not have these giant structures of the aliens.