Astronomers may have found giant alien 'megastructures' orbiting star near the Milky

[stevebowers]

John B wrote a little article about such a star, more than a decade ago
http://www.orionsarm.com/eg-article/5325e42d2eb4f
written in his unique style...

[totaleclipse1985]

also here: https://www.newscientist.com/article/dn2...LOBAL-hoot

Isn't a gradual dimming of 20% over a century exactly what you would expect from a dyson swarm/matrioshka brain construction? Assuming linear construction this would result in a 500year construction time which sounds perfectly reasonable for me given self-replicating nanotech for example.
For the missing infrared - wouldn't a matrioshka node produce only radiation close to the temperature of the cosmic background radiation because every next layer would utilize the waste radiation of the previous one? Has anyone done the math on that?

[stevebowers]

To produce radiation at the temperature of the CMBR, the outer shell needs to be many AU wide- especially since this is an F-Class star, brighter than our Sun.

In addition, if it were only a partial dyson, some of the inner layers would surely radiate through the gaps - I can't imagine how to avoid this using any configuration I'm familiar with.

[Dark]

By the way, I thought of JWST sun shield. At 1 a.u. the sun-facing side is at 85C and opposite one is at -233 C.

So I would imagine a swarm of billions similarly shielded habitats around this star...

P.S. Also some of excess radiation is radiated out of the sides. So, such a shield would appear cold face-on and warm when faced edge-on. But the edge area is rather small compared to face, so we might not see the warmer edges unless chance alighnment happens

P.P.S Also the sun-faced sides can be actively cooled or used as thermal engines with low-temp working fluid.

[stevebowers]

But we'd see the habitats on the far side of the Sun, since they face us. They would only radiate at 85C, and they would be partially obscured by the ones on this side; if the swarm obscures 20% of the star, then the far side will be 20% obscured as well. We would be looking at a sphere of scattered habitats a couple of AU across, 80% empty space with 20% of that obscured by the habitats on this side of the star. Maybe 16% of the far side of the sphere being visible at any time.

A difficult target to see, but only as difficult as some of the dust clouds that have been observed around various stars. In all probability this is a dust cloud of some sort, but one which is unique to astronomy.

[stevebowers]

Here's Anders Sandberg on the question of building a Dyson swarm in 100 years or so
http://aleph.se/andart2/space/what-is-th...son-shell/

[stevebowers]

http://arxiv.org/abs/1601.07314
KIC 8462852 did likely not fade during the last 100 years
Michael Hippke, Daniel Angerhausen
(Submitted on 27 Jan 2016)
A recent analysis found a "completely unprecedented" dimming of 0.165±0.013 magnitudes per century in the F3 main sequence star KIC8462852. This star is interesting, as it shows episodes of day-long dips with up to 20% dimming of unknown origin. We re-analyze the same Harvard archival Johnson B photometry and find comparable dimmings, and structural breaks, for 18 of 28 checked F-dwards (64%) in the Kepler field of view. We conclude that the Harvard plates photometry suffers from imperfect long-term (1890--1989) calibration. The most likely explanation for the century-long dimming of KIC8462852 is thus a data artefact, and it is probably not of astrophysical origin.

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Science - always changing its mind...

[stevebowers]

And a response by Bradley Schaefer to Michael Lipke's paper (previous post)

http://www.centauri-dreams.org/?p=34933

If there were any systematic problems for the DASCH data with Tabby’s star, then we should see the exact same dimming trend in the check stars as is seen for Tabby’s Star. But we do not. These ‘check stars’ serve as the classic control study in science. They serve as proof that neither the check stars nor Tabby’s Star have any substantial systematic problem. They serve as proof that Hippke’s title is wrong.

[tmazanec1]

Well, I hate to wait, but the next dimming is "scheduled" for May 2017. If it happens, we will be looking in real time with spectroscopes, etc. If it doesn't, a lot of periodic models go in the wastebasket.
Whichever happens, KIC 8462852 deserves the nickname "WTF-001"!

[tmazanec1]

Is it a Ringworld?
http://www.datasciencecentral.com/profil...f-transits