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“Alien Megastructure Is Not The Cause Of The Dimming Of Tabby’s Star ” (Design Inference filter in action; Sci Fi Fans disappointed)


According to SciTech Daily in a January 3, 2018 article, Tabby’s star, aka KIC 8462852, has had a mysterious brightening and dimming cycle.  (Such a cycle, of course raises the interesting thought of the erection of a Dyson Sphere or a similar megastructure.)

As the article reports:

Artistic illustration of an irregular dust ring at Tabby’s Star (HT: SciTech Daily & NASA/JPL-Caltech)

>>A team of more than 200 researchers, including Penn State Department of Astronomy and Astrophysics Assistant Professor Jason Wright and led by Louisiana State University’s Tabetha Boyajian, is one step closer to solving the mystery behind the “most mysterious star in the universe.” KIC 8462852, or “Tabby’s Star,” nicknamed after Boyajian, is otherwise an ordinary star, about 50 percent bigger and 1,000 degrees hotter than the Sun, and about than 1,000 light years away. However, it has been inexplicably dimming and brightening sporadically like no other. Several theories abound to explain the star’s unusual light patterns, including that an alien megastructure is orbiting the star.

The Hertzsprung-Russell diagram of luminosity vs Spectral Class etc

The mystery of Tabby’s Star is so compelling that more than 1,700 people donated over $100,000 through a Kickstarter campaign in support of dedicated ground-based telescope time to observe and gather more data on the star through a network of telescopes around the world. As a result, a body of data collected by Boyajian and colleagues in partnership with the Las Cumbres Observatory is now available in a new paper in The Astrophysical Journal Letters. [–> Cf. at Arxiv, here]

“We were hoping that once we finally caught a dip happening in real time we could see if the dips were the same depth at all wavelengths. If they were nearly the same, this would suggest that the cause was something opaque, like an orbiting disk, planet, or star, or even large structures in space” said Wright, who is a co-author of the paper, titled “The First Post-Kepler Brightness Dips of KIC 8462852.” Instead, the team found that the star got much dimmer at some wavelengths than at others.>>

Thus, the (inevitably provisional) inference is that:

>>“Dust is most likely the reason why the star’s light appears to dim and brighten. The new data shows that different colors of light are being blocked at different intensities. Therefore, whatever is passing between us and the star is not opaque, as would be expected from a planet or alien megastructure . . . ”>>

Let’s try inserting a TED Talk by the lead author of the paper, Tabetha Boyajian — shows in the edit, problems looks like in the final post — will request intervention:

Megastructures and Dyson Spheres? Wikipedia is handy as a 101:

>>A Dyson sphere is a hypothetical megastructure that completely encompasses a star and captures most or all of its power output. The first contemporary description of the structure was by Olaf Stapledon in his science fiction novel Star Maker (1937), in which he described “every solar system… surrounded by a gauze of light traps, which focused the escaping solar energy for intelligent use.”[1] The concept was later popularized by Freeman Dyson in his 1960 paper “Search for Artificial Stellar Sources of Infrared Radiation“.[2] Dyson speculated that such structures would be the logical consequence of the escalating energy needs of a technological civilization and would be a necessity for its long-term survival. He proposed that searching for such structures could lead to the detection of advanced, intelligent extraterrestrial life. Different types of Dyson spheres and their energy-harvesting ability would correspond to levels of technological advancement on the Kardashev scale.

Since then, other variant designs involving building an artificial structure or series of structures to encompass a star have been proposed in exploratory engineering or described in science fiction under the name “Dyson sphere”. These later proposals have not been limited to solar-power stations, with many involving habitation or industrial elements. Most fictional depictions describe a solid shell of matter enclosing a star, which is considered the least plausible variant of the idea. In May 2013, at the Starship Century Symposium in San Diego, Dyson repeated his comments that he wished the concept had not been named after him.[3]>>

EarthSky dot org has a nice conceptual in-construction illustration of a full-bore Dyson Sphere (where, all sorts of variations from a ring of satellites on up have been envisaged):

EarthSky dot org conceptual illustration of a Dyson Sphere under construction using a Moon as a mine for materials

All of this is interesting and stimulating, but how does the Design inference come in?

ANS: We see a real-world example of the design inference explanatory filter at work, here drawing the conclusion that a dust cloud is a better explanation than a considered Megastructure. But also, notice, a design alternative was in fact considered as a possibility.

Let us look at the per aspect form of the filter:

Here, we have a contingent entity, a star. This we can classify per luminosity and temperature as F-type, main sequence (Cf. HR diagram) in Cygnus, estimated to be 1280 LY away. It exhibits a feature of interest, “inexplicably dimming and brightening sporadically like no other.”

The spectral investigation makes this contingent complexity likely to be a result of an irregular dust cloud and there are obviously models being developed and tested.

In short, the Design Inference explanatory filter is here seen in real world action. Though, for all of us who are rooting for Little Green Men, design is not currently the strong horse to bet on. END

F/N: it is almost amusing but then truly sad, to see how a technical issue that goes to the heart of the scientific case for inferring design is raised i/l/o a concrete, real world, live case that illustrates how the same logic as is portrayed above is implicitly at work; though compounded by Sagan's "extraordinary claims" form of Cliffordian evidentialism -- which BTW also directly shows the significance of epistemological issues in scientific work. The professed concern on alleged lack of technical subject matter is clearly less than something to be taken at face value. KF kairosfocus
New, thanks the vid is there now. KF kairosfocus
F/N3: Of course, there is an argument out there that a dust of particles on that scale needs to be renewed on timescales of days given the "broom" of radiation pressure. So, asteroid mining is on the table too. KF kairosfocus
F/N2: In the TED Talk, the presenter began with Sagan's extraordinary claim assertion. This assertion is actually wrong. Claims -- extraordinary or not -- need sufficient evidence or adequate evidence, not "extraordinary" evidence. That is an invitation to selective hyperskepticism, a bane of serious thought in today's age. KF kairosfocus
F/N: I tried to add a TED talk, but WP stripped it out from the final posting, though it appeared while in the edit. I will request an intervention. KF kairosfocus
ABSTRACT of the looks like ~ 200 author paper: The First Post-Kepler Brightness Dips of KIC 8462852 Tabetha S. Boyajian, Roi Alonso, Alex Ammerman, David Armstrong, A. Asensio Ramos, K. Barkaoui, Thomas G. Beatty, Z. Benkhaldoun, Paul Benni, Rory Bentley, Andrei Berdyugin, Svetlana Berdyugina, Serge Bergeron, Allyson Bieryla, Michaela G. Blain, Alicia Capetillo Blanco, Eva H. L. Bodman, Anne Boucher, Mark Bradley, Stephen M. Brincat, Thomas G. Brink, John Briol, David J. A. Brown, J.Budaj, A. Burdanov, B. Cale, Miguel Aznar Carbo, R. Castillo Garcia, Wendy J Clark, Geoffrey C. Clayton, James L. Clem, Phillip H Coker, Evan M. Cook, Chris M. Copperwheat, J. Curtis, R. M. Cutri, B. Cseh, C. H. Cynamon, Alex J. Daniels, James R. A. Davenport, Hans J. Deeg, Roberto De Lorenzo, Thomas De Jaeger, Jean-Bruno Desrosiers, John Dolan, D. J. Dowhos, Franky Dubois, R. Durkee, Shawn Dvorak, Lynn Easley, et al. (156 additional authors not shown) (Submitted on 2 Jan 2018) We present a photometric detection of the first brightness dips of the unique variable star KIC 8462852 since the end of the Kepler space mission in 2013 May. Our regular photometric surveillance started in October 2015, and a sequence of dipping began in 2017 May continuing on through the end of 2017, when the star was no longer visible from Earth. We distinguish four main 1-2.5% dips, named "Elsie," "Celeste," "Skara Brae," and "Angkor", which persist on timescales from several days to weeks. Our main results so far are: (i) there are no apparent changes of the stellar spectrum or polarization during the dips; (ii) the multiband photometry of the dips shows differential reddening favoring non-grey extinction. Therefore, our data are inconsistent with dip models that invoke optically thick material, but rather they are in-line with predictions for an occulter consisting primarily of ordinary dust, where much of the material must be optically thin with a size scale <<1um, and may also be consistent with models invoking variations intrinsic to the stellar photosphere. Notably, our data do not place constraints on the color of the longer-term "secular" dimming, which may be caused by independent processes, or probe different regimes of a single process. Comments: 19 pages, 8 figures, accepted for publication in ApJL Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Earth and Planetary Astrophysics (astro-ph.EP) Cite as: arXiv:1801.00732 [astro-ph.SR] (or arXiv:1801.00732v1 [astro-ph.SR] for this version) kairosfocus
“Alien Megastructure Is Not The Cause Of The Dimming Of Tabby’s Star ” (Design Inference filter in action; Sci Fi Fans disappointed) kairosfocus

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