This paper takes part in the series essay competition of “great science” of Recordunkown.
Since human beings came out of the earth and saw the vast universe, they no longer doubted the existence of alien civilization. But if we want to prove the existence of alien civilization, we need to find the trace of alien civilization. To this end, scientists have launched the plan to explore extraterrestrial civilization through various methods.
In 1977, scientists launched voyager-1 and voyager-2, both of which carried a golden disc, which recorded all kinds of information about life on earth and human civilization, as well as the earth’s coordinates. The goal of Voyager is to go out of the solar system and search for alien civilization. Scientists expect that Voyager will be captured by alien civilization after it goes out of the solar system, and then the alien civilization will get in touch with human beings according to the information on the disc.
Although Voyager has now crossed the Kuiper belt into interstellar space, according to scientists’ new division of the solar system, it may take more than 10000 years for them to fly out of the solar system. As a result, we have little hope for Voyager to explore alien civilization, because it is only possible to fly out of the solar system to find alien civilization.
In addition to sending exploration spacecraft to look for alien civilizations, scientists also look for possible alien civilizations by looking for earth like planets very similar to the earth. But this way, we can only determine that a planet is very similar to the earth, there may be life or civilization, but we can not directly observe the details of the planet. Therefore, there is little hope for this method to find alien civilization.
Later, scientists focused on searching for possible signals of alien civilization in the universe through radio telescopes. This method is still possible to discover alien civilization. If the alien civilization has developed from the parent star to the interstellar, and even has become a powerful interstellar civilization, then radio communication is a necessary technology. The more powerful a civilization is, the stronger its radio communication technology is.
As long as we can find such signals, it is possible to find the existence of alien civilization. However, there is another difficulty in this method, that is, to crack the mysterious signals. We need to know that alien civilization and human civilization may be two completely different civilizations, and the mode of wireless communication technology may also be completely different. We have no understanding of the language and words of alien civilization, and the possibility of naturally deciphering the signals of alien civilization is also very rare. Therefore, it seems theoretically possible to search for extraterrestrial civilization by searching for extraterrestrial civilization signals, but it is also very difficult to achieve.
In addition to the above three ways to search for alien civilizations, scientists have also come up with another way, that is to observe and search for huge man-made objects built by alien civilizations. Such man-made objects may be spaceships as big as we can’t imagine, such as spaceships as big as planets and stars. If it is a small man-made object, we may not be able to observe and find it, but if it is a particularly large and conspicuous man-made object, it may be observed by us.
Among the numerous man-made objects, the most likely thing that scientists think of is the Dyson sphere, which is a kind of advanced civilization man-made object that scientists guess. It is a device built around the star to absorb the energy of the star. The development of any civilization can not do without energy. When a civilization develops to the interstellar, the resources and energy of the parent star may have been exhausted, and the available energy can only be obtained from space.
One of the most powerful energy sources in space is stellar energy. So scientists guess that when a civilization develops into a second-class civilization, it will use stellar energy to build huge buildings similar to the Dyson sphere to absorb stellar energy. If there are such huge man-made buildings around a star, the brightness of the star must have a very obvious change in light and dark. And stars are very dazzling objects in the universe, which can be observed by astronomical telescopes.
So are there stars in the universe that have very obvious changes in light and dark? The answer is yes. One of the most famous stars is Tabby, a star about 1480 light-years away from earth, between Lyra and Cygnus. Kepler space telescope survey data found that the brightness of tabby star often changes greatly, the biggest one actually dropped by 22%! No known astronomical phenomenon can explain this event.
Therefore, scientists speculate that there may be a Dyson sphere around the star, which blocks the brightness of the star. When the Dyson sphere absorbs and collects the energy of the star, there may be a very obvious light dark change. So tabby is a star that scientists are paying close attention to. In addition to Tabby, there are two stars with irregular light variation, which are code named epic 204278916 and vvv-wit-07.
In addition to the irregular light variation of the above three stars, scientists also found a star named asassn-v j213939.3-702817.4 in May 2014, which is about 3000 light-years away from the earth. In the five years since its discovery, the brightness of this star has been very stable. However, some time ago, scientists observed that its brightness dropped by 70% in two days, and then returned to normal. What’s going on?
You know, the biggest change in light and dark of tabby star is only 20%, while the star 3000 light-years away from the earth has dropped by 70% in two days, which indicates that there may be a huge shelter around it. Only a very large shelter can cause a huge change in light and dark, but what is this huge shelter?
Astronomers also put forward different views on this. Some people think that it is possible that the advanced civilization built a more sealed and huge Dyson sphere around the star in two days, wrapping the star. But if so, why did the change last only two days and then return to normal? The star’s brightness has not changed significantly in the past five years, indicating that there were no particularly large objects around it in the past.
Some astronomers suggest that there may be dense dust rings or planets around the stars, but this conjecture has been denied by more scientists. Until now, scientists have no idea why the star’s brightness plummeted 70% in two days? More and more scientists still think that the sudden change of brightness is more likely to be caused by some astronomical phenomenon. It’s just that we don’t know much about the universe, and we can’t go near to observe it. Naturally, we can only explain it through various conjectures.
Of course, if this star in the future, like Tabby, often appears very obvious light and dark changes, then the possibility of the existence of Dyson sphere is very high. Although scientists speculate that there is a Dyson sphere by observing the light and dark changes of stars, we can’t directly observe the alien buildings, so these are just conjectures.
There are only two ways to really understand the existence of alien civilization. One is that human beings can become an interstellar civilization and go out of the solar system to explore galaxies suspected of having alien civilization. The other is that alien civilization came to the solar system to contact with human beings. At that time, I believe that everyone would not doubt the existence of alien civilization. We are looking forward to this day.
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