By the recent research and observation, there is a star numbered KIC-8462852 spread a strange flux and decreasing of its brightness without clear periodicity. By the suspects, people have already given and the Drake equation, there is no significant evidence to prove that that is an impossibility; therefore, the inference is there is a possibility to be a Dyson Sphere, which means there is also have a possibility to have another civilization.
Dyson Sphere, astronomy, star, KIC-8462853, alien
According to the latest experimental observation conducted by the Planet Hunter Program by Zooniverse , the brightness of star KIC-8462852 has decreased about 22% surprisingly without apparent periodicity by Boyajian’s confirming “These show that the flux is relatively constant for most of that time, but is punctuated by a number of substantial dips in flux, including a 15% drop near day 800, and a whole sequence of dips (with one reaching a depth of 22%)”(Boyajian 3). Such kind of exciting and strange behavior of star KIC-8462852 causes an extensive and hot discussion, and some media reports even show it is a sign of discovery of alien, which caused a considerable influence in public. There are many different kinds of theories about this unnormal behavior such as Eva claim that KIC-8462852’s behavior is caused by the transit of a large comet family. (Bodman 1), a cloud of gas, error of the instrument etc.. However, the study and research are just at the beginning, because the specific and one-directing reports are not shown yet. Here comes the question—Is KIC-
8462852 A Dyson Sphere?
What is A Dyson Sphere?
The first thing will be going to talk about is: What is Dyson Sphere? Recalling Stapledon’s description, Dyson proposed similar structures in a scientific paper in 1960. Dyson realized that alien civilizations could be recognized by their waste heat, which would be detectable as infrared radiation. Dyson proposed that really advanced civilization would re-engineer thrive solar systems, perhaps dismantling planets to form a shell of satellites around their star to capture its energy.( Tate, “Dyson Spheres: How Advanced Alien Civilizations Would Conquer the Galaxy (Infographic)”) We could divide civilizations to three levels by Kardashev scale :I civilization, which means this civilization could completely use the whole energy of its living plane and its satellite; II civilization, which means this civilization could collect the whole energy of Galaxy; III civilization, which means this civilization could completely use the whole energy of the galactic system. (Tate, “Dyson Spheres: How Advanced Alien Civilizations Would Conquer the Galaxy (Infographic)”). Our civilization level is 0.8 which means we even not a civilization.
In the observation program “Planet Hunter” by Zooniverse which a public welfare program is, for people to find interesting stars by human eyes which hard for the instrument to do. Volunteers found an interesting planet which shows a strange behavior. (Boyajian 2) The Star KIC-8462852 is not distributing light evenly but looks like be covered by something, scientists are already excluded from the problem of data error and aircraft covered, people give a lot of reason for that.
The first guessing comes to people’s mind is the problem of instruments. By the words from Boyajian: “We confirm that the dipping signals in the data are not caused by
any instrumental or data processing artifact, and thus are astrophysical in origin.”(Boyajian 2) Before publishing the paper, people have already checked the data analysis software and detector of Kepler telescope, photons become dark on several different pixels on CCD, and four CCDs on the telescope show this situation in different time（Coughlin et al. 2014）, which mean it cannot be problem of CCD, some other teams also built and check the original data with the same result, so it is nearly impossible to be this kind of situation.
Covering by Asters in Solar System
Calculations show that if the shelter is located inside the solar system, it must have a diameter of at least 1 astronomical unit, a distance of 10,000 astronomical units from the Sun (ie the scale of the Kuiper Belt to the Oort Cloud), and a distance away from the ecliptic plane (Boyajian’s yellow tube of 62 degrees). . Considering that humans have little knowledge of the outer solar system, it is unclear how large this possibility is.
Surrounded by a star-stabilized object (such as a black hole) and its accretion disk
However, the probability that it happens to be seen by us is very small, only one in a million. Considering that only 200,000 stars were observed by Kepler, the probability is very small.
Comet or other
Boyajian’s original paper already discussed the situation of comets (Boyajian “What the flux” 17). Bodman and Quillen of the University of Rochester believe that the second large drop in luminosity (that is, a decrease around 1500 days) can be explained by the same group of comets(“Where’s the flux” 2), most of which are in the same orbit, possibly by the same event. Generated, such as the disintegration of planets or the gravitational disturbance of companion stars. To block 20% of the main star’s light, it requires 30 comets with a radius of 100 km or 300 with a radius of 10 km. It is still difficult to explain the decline of the first time (that is, around the 800th day) because the first decline is smoother and slower, and the number of comets required increases to 70 (radius 100 km) or 700 respectively. (10 km radius). The comet’s elliptical orbit has a high eccentricity, and only when it passes through the near star point can it produce a significant super infrared, and the total mass does not exceed the upper limit given by Thompson.
Low-temperature cyclic substance
The edge of this ring happens to be facing us. However, Thompson’s millimeter/submillimeter-wave observations do not tend to have a large number of such substances(Thompson KIC 8462852 faded at an average rate of 0.164±0.013 magnitudes per century from 1890 to 1989” 1), and this hypothesis cannot explain the continuous darkening that occurs during the entire observation period of the Keplerian telescope.
The activities of the stars themselves
such as sunspots and magnetic fields. The Boyajian star’s rotation period is 0.88 days, and sunspots or rotate with the stars, but there is no 0.88-day cycle in the decline of the light curve, so it does not match. As the F-type main sequence star, the outer layer of Boyajian star has no convection zone and the rotation is fast, and there should be no obvious activity cycle. So this assumption is very unlikely.
The sunspots in the polar regions
This explains why the drop curve does not have a 0.88-day period, and long-term darkening can also be explained by increasing the area of sunspots. However, this does not meet the characteristics of early-type F main sequence stars and is therefore unlikely.
The pulsation of the star itself.
In this case, the light changes of the stars are often periodic, and the time scale is also inconsistent with the Boyajian star. No one known pulsation mechanism can explain this. Therefore, it is also unlikely.
Artificial celestial body
The unnatural-made building which uses for collecting energy from a star such as Dyson Sphere, which is the possibility people most care about. An easy way to test this possibility is to use the absorption characteristics of different materials and compare the stellar distances obtained by various methods. (Kepler “Data for KIC-8462852” 22) The panel is a geometric absorber that blocks the stars in different wavelengths indiscriminately, and the absorption of the interstellar material is weaker for red light with longer wavelengths, i.e., the reddening effect. The method of obtaining the stellar distance by comparing the radiation fluxes of different wavebands usually considers the correction brought about by reddening. The range captured by the parallax of the triangle is a pure geometric effect and has nothing to do with the brightness. Therefore, if ESA’s astrometric satellite, GAIA, gets a significantly more considerable distance through the triangulation parallax than the traffic-reddening method, it supports this possibility.
The Drake Equation
The Drake equation is used to counting the number of communicating civilizations in the universe, or more simply, to determine the probability of finding intelligent life in the world (Drake Drake Equation 1)
The first proposed equation by radio astronomer Frank Drake in 1961 computes the number of civilizations to communicate by multiplying several variables. It is usually written as follows according to the search for extraterrestrial information (SETI).
N = R * · FP · ne · fl · fi · fc · L
N = number of civilizations in which electromagnetic radiation in the galaxy can be detected.
R * = formation rate of stars suitable for the development of intelligent life.
fp = Percentage of stars with a planetary system.
ne = number of planets with the environment suitable for life for each solar system.
fl = Percentage of an appropriate planet in which life appears.
fi = Percentage of life with a planet on which intelligent life emerges.
fc = Percentage of civilizations developing technology to release detectable signs into space.
L = the length of time that such civilization releases a detectable signal into space.
Depends on the equation, most of the factor we cannot find the specific data, all the date in the comparison are unsure, such as fl: The fraction of suitable planets on which life actually appears, which is the most unsure part of the whole equation because the planet could be destroyed by complex reasons. On the other hand, how could we know if there is another civilization in The Milky Way because it is super hard for them to spread information to here? All in all, the Drake equation shows that there is a possibility to have aliens even this equation is only base on a human being.
KIC 8462852’s doubts have not yet been solved, and progress from May to the present is still very limited. What has been published or published at present is the analysis of historical data. There have been a large number of observations since the darkening in May. The results have not yet been published. In these analyses of historical evidence, two phenomena have been studied differently from each other. Support is therefore reliable, that is, the darkening from 2009 to 2013, and the stellar color becoming more “red” when it is dimmed. “Also, based on individual, rough observations cannot prematurely conclude. For example, a site posted sodium and calcium lines before and after blocking, it was not the result of careful processing, and it did not see the publication of research papers. The reliability was in doubt, so it was not considered for the time being. But the thing is, there is no evidence to directly negative the possibility to be a Dyson Sphere star, therefore the existence of that is still positive.
Boyajian, T. S., LaCourse, D. M., Rappaport, S. A., Fabrycky, D., Fischer, D. A., Gandolfi, D., … & Olah, K. (2016). Planet Hunters IX. KIC 8462852–where’s the flux?. Monthly Notices of the Royal Astronomical Society, 457(4), 3988-4004.
Schuetz, Marlin, et al. “Optical SETI observations of the anomalous star KIC 8462852.” The Astrophysical Journal Letters 825.1 (2016): L5.
Bodman, E. H., & Quillen, A. (2016). KIC 8462852: transit of a large comet family. The Astrophysical Journal Letters, 819(2), L34.
Montet, B. T., & Simon, J. D. (2016). KIC 8462852 faded throughout the Kepler mission. The Astrophysical Journal Letters, 830(2), L39.
Drake, F. (1961). The Drake equation. See http://www. activemind.com/Mysterious/Topics/SETI/drake_equation. html.
Schaefer, B. E. (2016). KIC 8462852 faded at an average rate of 0.164±0.013 magnitudes per century from 1890 to 1989. The Astrophysical Journal Letters, 822(2), L34.
Boyajian, T. S.; LaCourse, D. M.; Rappaport, S. A.; Fabrycky, D.; Fischer, D. A.; 等. Planet Hunters X. KIC 8462852 – Where’s the Flux?. 11 September 2015. arXiv:1509.03622 [astro-ph.SR]. Submitted to Monthly Notices of the Royal Astronomical Society.
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