Comets can't explain weird 'alien megastructure' star after all | Hacker News Reader

Comets can't explain weird 'alien megastructure' star after all

newscientist.com

172 pointsaburan28117 comments

>>> “The alien-megastructure idea runs wrong with my new observations,” he says, as he thinks even advanced aliens wouldn’t be able to build something capable of covering a fifth of a star in just a century. What’s more, such an object should radiate light absorbed from the star as heat, but the infrared signal from Tabby’s star appears normal, he says.

That seems a rather unambitious approach to possible alien tech. We today clearly could not build, or think of how to build, such structures. That isn't to say that the technology isn't possible, just that we do not understand it. If aliens were able to create and fly structures of such size I think it safe to say they would also be in possession of tech we cannot contemplate.

In general I agree, but the lack of radiation is a real problem - we would need to have some fundamental error in our understanding of thermodynamics for their tech to be capable of that. That, or the structure itself isn't collecting the energy but only [somehow] redirecting visible wavelength light.

Like a mirror? Or a mirror that selectively reflects certain wavelengths but not others?

Guys these are just solar panels. Their race is better at alternative forms of energy than us.

Solar panels heat up. It's the law!

Perhaps they use the heat very efficiently?

No dice. Conservation of energy and other thermodynamic laws say that [a] there are limits to efficiency, and [b] if you absorb energy you must re-radiate it. Among other things. There's no point in speculating about the blatantly unphysical. @Sharlin is right, it's just "Goddidit" dressed up.

Do any of them say it must be re-radiated omni-directionally as infra-red light?

Pretty much.

You can make it cooler than infra-red light (like microwaves), and you can irradiate for half a sphere, or even a bit less. But that's all.

Don't forget entropy. Matter can absorb energy without necessarily radiating it immediately. Two objects can be the same temperature but of totally different energy. The easiest to understand is probably phase changes. Ice can melt into water, absorbing energy, without changing its temperature. Even stranger, ice can sometimes melt, still absorbing and retaining energy from its surroundings, while the temperature of the system actually drops (ie if you pour salt on ice).

what if they were getting the energy from this star system and "beaming" it somehow somewhere else? you would not get any IR from that because it would not be used in this system at all

The report seems to be saying that the IR is unchanged - i.e. there is IR, it's just what is expected from the star. As the other commenter suggested, it would need to be some reflector which was IR-transparent, which would be a pretty strange setup.

Could this be explained by a black hole, slowly slowly siphoning matter from the star? Maybe it's behind the star and we're less likely to observe the radiation from it..

You shouldn't be getting downvoted for this, but also no.

A black hole would have an accretion disk in this case and be a very bright object. It would also be in orbit so we would've spotted the traversal of it given the timespan or the matter siphon if it was in a large orbit.

If there's no plausible model that involves aliens and explains the observations, it's not science. "Advanced aliens did it in a way we don't understand" is basically a "Goddidit" argument.

Aliens of the gaps?

https://en.wikipedia.org/wiki/God_of_the_gaps

There is a difference between claiming that aliens have done something, and being critical of those too dismissive of the possibility.

This isn't goddidit. That argument is used to end a debate, to say that the how is unknowable. A claim that aliens are doing something is the opposite, a call for more careful and complete scientific scrutiny.

The time to investigate outlandish hypotheses is after the space of more plausible ones is exhausted.

So let's hear some more plausible ones.

If you assert that no intelligent extraterrestrial entities are capable of harnessing, redirecting, or otherwise manipulating the light from a star, then you have a burden of proof of your own to meet.

I think the burden of proof is heavy and squarely on those who propose so lightly that "advanced aliens" do such things.

There's plenty of "burden of proof" to go around, I think. That's what makes this such an interesting (if futile) question.

It comes down to the amount of surprise we should experience at finding evidence of any ET civilization. Arguably, given the sheer number of other worlds that we now know to exist, it's surprising that we haven't found any such evidence.

At the same time, given the vast distances involved, it would be surprising if any evidence that we might find didn't consist of something truly unusual and spectacular on a stellar scale... something like a Dyson structure that only one in a million civilizations might be capable of creating. With our current observational tech, we'd never notice anything less.

In the OP, Sharlin used the term "outlandish." That's a value judgement, not a term of art. It's a judgment we're not qualified to make.

In Occam's Razor terms, "super-sophisticated aliens did it" is just about the most complicated answer with the most "entities" conceivable. It is a great deal simpler to hypothesize that we've missed some aspect of stellar dynamics that fits the observations. This is further boosted by the fact that we have a history of such things (pulsars, etc).

It may be true, but it is definitely a hypothesis sitting on the bottom of the list of sensible possibilities. Any rational analysis pretty much has to put "our understanding of stellar dynamics is missing something" multiple orders of magnitude more likely, given our current state of information.

In Occam's Razor terms, "super-sophisticated aliens did it" is just about the most complicated answer with the most "entities" conceivable.

Occam's Razor isn't a nuclear weapon. You still have to decide which entities are necessary and which are superfluous, presumably through some insight into the underlying premises.

In this case we simply don't have the perspective we need to decide what's "outlandish" (to use Sharlin's term) and what isn't. What's inherently outlandish about aliens? We're aliens, too, from the perspective of every other civilization that might exist.

See my other post -- some very credible authorities would say it's surprising that we haven't found evidence of any ET civilizations, given the number of possible habitats for them. What's almost certain is that the only such civilizations we could observe are the few who can deliberately alter the appearance of a star. Not only is it scientifically inappropriate to reject "Aliens did it!" as a hypothesis or to assign it an arbitrary (un)likelihood, but IMO we shouldn't even be surprised if that turns out to be the case. Alien civilizations are, or should be, no big deal.

The aliens are superfluous entities because "aliens did it by unknown mechanisms" has no additional explanatory power than "it occured by unknown mechanisms."

Depends on the question you ask. "What's interfering with this star's light?" is one question. "Can we find evidence suggestive of any other civilizations, specifically the kind who could build Dyson spheres?" is another.

Occam's Razor is a heuristic, not a law. I think you're misunderstanding what it is. It doesn't mean aliens are impossible. It means the rational conclusion based on the evidence puts the probability of aliens very low. This is because, on the evidence we have right now, we know we are far more likely to be missing some quirk of science than to be finding aliens, because we have on multiple occasions found we've been missing out on science. We don't need aliens to explain this yet.

Show me a coherent information signal coming from this star and I'll change my tune in a heartbeat, but "the brightness of this star is behaving a bit oddly" just isn't that spectacular of a signal.

So let's entirely dismiss this possibility even though we have no idea what it is? That seems equally unreasonable.

Eh, outlandish hypotheses can be worth exploring once they exist as scientific hypotheses, i.e., when there is something that forms a basis for a falsifiable prediction, even if more mundane explanations haven't been rejected.

OTOH, "aliens did it by unknown means" is experimentally undistinguishable from "it happened by unknown mechanisms" more generally, and untestable.

If that's true why do scientists take seti seriously and ask to increase its funding?

The attitude has always baffled me in fact. We constantly say that alien life is likely due to the size of the universe yet we can't use them as an explanation for observed phenomenon.

A hypothesis that makes testable predictions is perfectly valid science even if it involves aliens. "Aliens did it" in itself is not a scientific explanation. Aluen life is probable a priori just given the size of the universe; unfortunately we also have all sorts of other evidence that technological alien civilizations are nowhere near us.

With SETI, we explicitly make the assumption that any prospective aliens are using communications technology that can be intercepted by us.

> With SETI, we explicitly make the assumption that any prospective aliens are using communications technology that can be intercepted by us.

And they probably are not. :-)

That's what I suspect. From what I understand, we wouldn't be able to detect our own radio broadcasts from more than half a light year away. The only realistic way in which we might detect alien radio signals is if they were either really close, or they're using a focused beam aimed directly at us. Which would imply they know we're here and listening. It all seems a bit unlikely.

Detecting alien megastructures, though, there might be something to that.

Extraordinary claims require extraordinary proof. That's why you'll see researchers working hard on all of the ordinary explanations of an observation, for a long time, before entertaining an extraordinary explanation.

And it is extraordinary claims that sometimes spur the imagination towards scientific action. Creativity works in many forms.

"A plausible model" is the key phrase. There's a huge difference between postulating that aliens might exist and produce radio broadcasts (something which we can already do, and understand very well) and that aliens might exist and be able to not only build something larger than a hundred planets, but build it in ten years. We don't even have a theory about the sort of engineering that might be required for that--it's pure speculation. And that's the problem.

>but build it in ten years.

A hundred years, actually. I made the same mistake reading the article and had to do a double take.

Ah, indeed. Fair point.

I think my argument still stands, though--even a hundred years for something of this scale is beyond any science we can reasonably hypothesize about. Doesn't mean we can't speculate, just that it's not terribly constructive speculation.

I think your view of what science is is a little too narrow. "Aliens did it in a way we don't understand, yet" is a hypothesis, which could be supported or refuted. The famous quote by Asimov is 'The most exciting phrase to hear in science, the one that heralds new discoveries, is not "Eureka" but "That's funny..."'

We've got something funny here, which may be (probably is?) nothing new, or may be exciting.

It is a conjecture or speculation; it is not a hypothesis, in the scientific sense, because without something more than "some way we don't understand", it makes no falsifiable predictions of future observations.

Now, speculation of this type can be the starting point to developing a testable hypothesis, so its not completely outside the scientific process, but it's far sorry of even a hypothesis.

Thanks for the point, I agree if we're speaking precisely and not colloquially. But...

> "its not completely outside the scientific process"

Here you unfairly (imo) diminish the role of wonder and speculation in science, which isn't something at the fringes of it, but part of the very soul and essence of it.

There is an unfortunate side effect of the rationalism movement that the (mostly correct) dismissal of religious explanations and pseudoscientific ideas: A lot of people who should know better also dismiss philosophy, conjecture and other ideas that don't have a firmly established theory as unscientific. These things are an important part of the scientific process. A lot of the key scientific tools and knowledge we have today started out as philosophical riddles.

Ironically, this same mistake has been made time and time again throughout history when science has made great strides. Someone points out that "that's funny", and are immediately shot down for coming up with ridiculous ideas that are not supported by the current theories.

This might not describe OP, but it's a pretty common phenomenon that often shows up in discussions where the boundaries of our current scientific knowledge are close. E.g. AI, the un-observable part of the universe, experiments that seem to break physics (e.g. the RF resonant cavity thruster), what is consciousness, etc.

And for every outlandish hypothesis that turned out to be true there have been a hundred for which a much more mundane explanation has sufficed. As Carl Sagan said, "They laughed at Columbus, they laughed at Fulton, they laughed at the Wright brothers. But they also laughed at Bozo the Clown."

Many of us yearn for novel, exciting discoveries with extraordinary explanations. The desire for novelty is a fundamental part of the human condition, and alien intelligence is one of the most thrilling, evocative, thought-provoking ideas that exist. However, the very fundamental point of the scientific method is to explicitly work against this bias - to ensure we're pursuing the truth and not our pet ideas.

As I brought up in another comment, it is wrong to single out "aliens" in the vast space of hypotheses just because that concept happens to be especially accessible and fascinating to laypeople. There are a plenty of possible explanations that are astrophysically novel and interesting and don't involve such a huge multiplication of entities as the aliens hypothesis does.

>And for every outlandish hypothesis that turned out to be true there have been a hundred for which a much more mundane explanation has sufficed.

A 1% probability of aliens seems pretty significant to me. Obviously it's more likely that it's not aliens, and no one disagrees with that. But the fact that it's even a possibility is very interesting and makes it worthy of investigation.

Anyway there isn't anything inherently unlikely about aliens. You make it like it's incredibly unlikely that aliens exist, so any hypothesis that includes them must be incredibly unlikely. A lot of people have higher prior probabilities on the existence of aliens.

"Aliens exist" and "an advanced technological civilization built a physics-defying megastructure around this specific star" have rather drastically different prior probabilities.

Anyway, I'll give the megastructure conjecture much more weight the second someone in the research community suggests it, preferably with some sort of a testable hypothesis. As far as I know it has been purely layperson speculation and as such not much more plausible than the ramblings of UFO believers or free energy cranks.

> As far as I know it has been purely layperson speculation

Well... almost.

It was originally suggested (as a highly unlikely but testable hypothesis) by astronomer Jason Wright. Then the press completely distorted his original point beyond recognition.

Methods for using Kepler data to identify artificial megastructures is the subject of research by several astronomers, including Luc Arnold (French National Centre for Scientific Research), Jason Wright (Penn State), and Geoff Marcy (UC Berkeley).

Here's a representative paper: http://arxiv.org/abs/astro-ph/0503580

Luc Arnold wrote a paper arguing that swarms of artificial structures would have certain unusual signature variations in their light curves. Jason Wright later pointed out that KIC 12557548 had similar predicted variations.

"Now, I don’t know what this is. Maybe it really is an evaporating planet (the best guess, I’d say). ... I’d bet my house on it not being aliens. But given that he went way out on a limb and predicted almost exactly this sort of thing, don’t you think Luc Arnold at least deserved a citation?"

This line, "I'd bet my house on it not being aliens," somehow got picked up by the media as "Astronomers have found super-advanced aliens," because that's how the press works.

So is it all lay speculation? Well, if you just mean credible astronomers aren't seriously arguing for this as a likely possibility, then yes. But if you mean there's no testable way to analyze Kepler data to distinguish between artificial and natural satellites... well... work in progress.

http://sites.psu.edu/astrowright/2013/03/09/artifact-seti/

>I'll give the megastructure conjecture much more weight the second someone in the research community suggests it, preferably with some sort of a testable hypothesis

Neither of those things should increase the probability at all. Just because a researcher believes it doesn't make it more likely to be true. Neither does the fact that it's testable.

Conversely, you shouldn't lower the probability because those things aren't true.

The Bayesian interpretation of probability is that it is a measure of subjective uncertainty. As such, a plausible model proposed by a credible member of the scientific community very much gives me a reason to update my priors.

Given that none of the natural explanations seem to hold water, I don't think it's unreasonable to consider the possibility of aliens. After all, many respectable astronomers have pointed out that the sheer number of stars makes it highly unlikely that aliens don't exist (well, there's still a lot of room between "alien life" and "alien civilization", but even the latter is a real possibility), and if they do, their blocking the light of their sun might actually be the most likely way we might detect them. (SETI by radiotelescope seems very unlikely to detect meaningful signals.)

So given that aliens might exist, and this might be the most likely way for us to detect them, it's certainly possible that it really is aliens this time.

Of course we don't know for certain. Not by a long shot. It is absolutely speculation, but it's reasonable speculation. We probably need a lot more data before we can say anything more specific about this. Maybe we do find a natural explanation after all. But it's not reasonable to ignore this possibility because some people don't want to discuss it.

And the person who proposed this is a real astronomer. Of course he didn't say it's definitively aliens. He said it's a real possibility. That doesn't mean a lot (because it's technically true of any star or exoplanet), but it's the most likely case we've got. And that's worth some attention.

> It is a conjecture or speculation; it is not a hypothesis, in the scientific sense, because without something more than "some way we don't understand", it makes no falsifiable predictions of future observations.

But it is falsifiable, for example we could falsify it by visiting the star and observing that there is no life in its solar system and no artificial satellites orbiting the star.

Technically, a scientific hypothesis requires it to be testable. Given this is at least partially scientific, the person saying it is a hypothesis should probably present a way to test if it is true or not. Given we don't know how to test for it yet, we may be left with continuing to explain what it is we're seeing without saying what it is. Which, I suppose, is a big challenge with space based discoveries.

The "nothing new" vs "aliens" is a false dichotomy. It might be a zillion things that are novel and exciting astrophysically but do not involve aliens or completely new physics. Heck, there are novel and exciting things on Pluto that we don't completely understand but no sensible researcher is shouting "aliens"!

Tell me how that is any different from "The Lord works in mysterious ways that we just don't comprehend yet"?

If it's not different, it suggests that you believe the chance of the existence of god is equal to that of there being advanced alien civilizations with technology beyond our comprehension.

Neither does anything in the way of real explanation, but if you believe that advanced alien civilizations are likely to exist (which is a fairly defensible argument based on things we DO know) or have existed (depending on how far away what we're observing is), the likelihood is quite different.

Not that I'm saying it's aliens.

But there are plausible ways they could have done it. They could, for example, be redirecting the IR radiation in some other direction.

Here's where the casual Bayesian reasoning that Daniel Kahnemann champions in Thinking Fast and Slow can come in handy.

What's the base rate probability for believing that unimaginable alien supertech exists? Is it even 1% at the moment? Now tweak that base rate based on this new ambiguous evidence -- evidence which experts seem to think has a natural explanation.

It doesn't rule out magic alien tech. But it doesn't make it all that much more probable either.

If you want to be more rigorous about it, what's your confidence that we will discover compelling, if not irrefutable, evidence that alien supertech exists in the next 5 years? Wager on your favorite online prediction market accordingly.

There is no percentage upon which to calculate. The reality that is this star is unknown to us. So there is a broad range of possibilities. Aliens is somewhere in that broad range, but as points within a range of knowns, the likelihood is incalculable. It's a few fixes points against an infinity. Bayesian is inappropriate in such circumstances.

You cannot argue in probabilities when you have zero prior events to go on.

The belief that large scale structures are dynamic is the basis of contemporary geology. Another is uniformatarianism [1]. That suggests that on the basis of observing short term changes in a star's brightness, our postulate ought to be that star's tend to vary in brightness. Our observations of other stellar phenomena such as nova's and black holes are consistent with this...as are quasars with the generalized case that the radiation from stars can fluctuate in short cycles even relative to human time.

This isn't to say that their may not be creatures [for some definition of "creature"] somewhere capable of constructing dyson spheres, but Occam's razor suggests that we focus on what is more likely. And the argument for the existence of alien technology that we cannot imagine is less well supported {because we have never encountered such a thing} than the argument for a natural process that we cannot imagine {because that is the history of scientific discovery}.

Postulating advanced technology developed by aliens based upon variation in a star's brightness is certainly no less scientific than postulating divine purpose upon finding seashell on a mountain top. It is certainly no more so either.

My money is geology over biology.

[1]: https://en.wikipedia.org/wiki/Uniformitarianism

That is a very well articulated reply.

The amount of data is so tiny and unreliable on top of that. We can't even be sure to be seeing a seashell. It's important not to ostracize who did this claim, but I too believe it will shortly turn into another example of jumping to conclusions violating Occam's Razor because the explanation excites us.

> My money is geology over biology.

Says the biology.

> “The alien-megastructure idea runs wrong with my new observations,” he says, as he thinks even advanced aliens wouldn’t be able to build something capable of covering a fifth of a star in just a century.

Oh, really? So we are speaking for alien's abilities now because we don't believe in them or their abilities to build things? That sounds like a cognitive bias. Here's another bias in the same vein:

> “No flying machine will ever fly from New York to Paris …[because] no known motor can run at the requisite speed for four days without stopping.” - Orville Wright

What Orville should have said was, "No flying machine will fly from New York to Paris until we develop a motor that can run at the required speed without stopping until it gets there."

And his second justification is even more baffling:

> "What’s more, such an object should radiate light absorbed from the star as heat, but the infrared signal from Tabby’s star appears normal, he says."

As if intelligent beings with an interest in capturing a fifth of a star's output would only be absorbing the human-visible spectrum of its radiance.

It's a thermodynamic argument, not an anthropocentric one. Irrespective of your technology, you can't just absorb all the energy of a star without re-radiating it, unless you want to cook yourself inside a gigantic space thermos.

Unless you can store, transmit and use it in a way that doesn't radiate energy omnidirectionally. My guess: universe's biggest indoor pot grow.

"Bro, point it away from that planet. That place is crawling with cops!"

Perhaps they are bouncing all that energy off-axis. That we cannot see the light doesn't mean it doesn't exist. Perhaps they are reflecting it back on the star for some reason. Or maybe we are seeing a mirror that is pushing some interstellar ship away from the host star. Luckily for us it would be traveling perpendicular to our vantage point, ie not coming here. Perhaps we should be looking for a mobile IR emitter somewhere nearby but accelerating away from this star. (I call dibs on the naming rights!)

You wouldn't be able to direct all of it off-axis. In order to do any meaningful work with it, some of it must be lost as heat or the entropy of the universe does not increase. That would violate the laws of thermodynamics. Essentially, you can reduce the entropy of an isolated collection of particles, but only at the expense of increasing the entropy of another collection of atoms, and only if you move the entropy around.

There's a slim possibility that a sufficiently advanced civilization has improved the efficiency of their process sufficiently to the point where the thermal radiation isn't measurable with our technology, but there still must be thermal radiation if any meaningful work is being done with the harvested energy.

Yes, but not necessarily thermal radiation aimed in the narrow direction necessary for us to detect it. Thermodynamics does not guarantee that all necessary information propagate in nice measurable spheres for all to see equally.

>unless you want to cook yourself inside a gigantic space thermos

Or cook someone else.

Couldn't you store the energy? Perhaps as antimatter?

Not without generating waste heat. It's a fundamental law of nature.

Right but you don't have to reradiate all the energy.

You kind of do. Energy available is a function of the difference between the input and output energy.

You can do useful work with the difference. It's not possible to harvest everything without also emitting some.

The R100 [1] that flew from the UK to Canada in 1930 in 72 hours used 6 of these monsters [2] in Wright's lifetime :

    Dry weight: 1,380 lb (628 kg)

    Power output: 670 bhp (500 kW) at 1,900 rpm

I wonder how he felt then

[1] https://en.wikipedia.org/wiki/R100

[2] https://en.wikipedia.org/wiki/Rolls-Royce_Condor

Not the same kind of flying machine - in an airship you can turn off the engines for a while if need be. But as early as 1919 you have https://en.wikipedia.org/wiki/Transatlantic_flight_of_Alcock...

Thet could have built it over hundreds or thousands of years. All we can infer is that if it is aliens, they deployed it in just a century.

When we're taking some solar-system-spanning megastructures, it's not clear that the dichotomy between building and deploying actually exists.

Maybe, but I think it is plausible there would be. Suppose we wanted to build a set of megastructures for collecting solar energy.

I'd guess we'd get the materials from the asteroid belt, or by taking apart Mars (or maybe Mercury or Venus, if we want to keep Mars for terraforming). I'd guess we'd set up the construction area for building the megastructures in the same general orbit where we get the raw materials, or we might move the materials to somewhere near Earth.

For deployment, though, we'd want to move these closer to the Sun, because you collect more energy per unit area the closer you are to the Sun. If we are putting them closer than Earth is to the Sun, though, we'd probably want them away from Earth's orbital plane so we wouldn't have the annoyance of them blocking out the Sun on Earth.

An observer at some other solar system is only going to see our megastructures if we've got them in an orbit whose plane intersects the observer's solar system. Those who can see them when they are under construction won't see them anymore when we shift them from construction orbits to deployment orbits, and those who can see them after we put them in deployment orbits won't see them before that when they are in construction orbits.

Another possibility is that what we are seeing is a redeployment. Maybe they were originally deployed in one configuration which from our vantage point was not visible, and then due to other future projects that configuration was no longer optimal and so they moved them to a new configuration which is visible to us.

It just makes sense to me that you would want to do as much of the construction on-site as possible. It's probably easier to ship raw materials through the solar system than assembled solar panels or whatever, which are potentially fragile. However, I must admit that edeployment is an interesting possibility.

The sci-fi novel "The Dark Forest" by Chinese writer Liu Cixin describes a similar phenomenon. In that case it was achieved by detonating bombs to produce "interstellar dust clouds", in order to cause flickering of the light from the star, visible from other systems.

Maybe the aliens from KIC 8462852 read Chinese sci-fi novels.

That's interesting. Perhaps there is some "natural" process that's producing dust clouds.

One possibility not mentioned is that the expert who eyeballed the old photographic plates to determine that there was a slight dimming did not do so under double blind conditions, and his assessment is tainted.

I don't mean to suggest this supports one hypothesis or another. But I'm not convinced his opinion on the dimming is so valuable if it was done without proper controls. There may very well have been proper controls, but unfortunately that didn't come through in the article.

The author used both methods, eye measurements, as well as digitized light curves from scanned plates. The paper has a graph of the latter. It's actually easy to replicate, the data is online.

http://arxiv.org/abs/1601.03256

http://dasch.rc.fas.harvard.edu/lightcurve.php

(You can download this star under the name "J20061546+4427248"; the KIC identifier doesn't seem to work).

Yes, came to say the exact same thing. I am not at all familiar with the photographic plate procedure, but it seems likely there is room for all sorts of tinkering with parameters like gain, lighting conditions, white balance, whatever that would allow any bias to shine through.

The aperture, exposure time, etc would all be recorded with the plate, so any bias would be absolutely minimal. Additionally, photographic plates don't have a single star on them, but rather a field of stars, so any overall bias would be applied equally to the entire field and weighted out.

The by-eye measurement was done by the author himself, so you have a point.

Still, apparently that measurement was much simpler (using only 131 of the plates; the digital measurement used 1232) and only done to be sure that the dimming was not a byproduct of the digital analysis method.

In other words, the real data for the paper is based on digital analysis, not on the by-eye measurement. More importantly, according to the paper, there were 5 control stars also measured digitally. They didn't show the dimming. The paper's graph (http://arxiv.org/pdf/1601.03256v1.pdf) plots two of them.

That could be possible - though we'd like to believe other wise the human eye isn't well calibrated. After all maps of the canals of mars came about from eye balling - and they never existed.

If you take a a purely reductionist approach to existence and sentience, there is no qualitative difference between comet dust cloud and alien megastructure. They're both natural processes, just differing in the degree of complexity.

Hydrogen + time = message board wank

Most would disregard this as a simplistic, unscientific thought, but the problem is they haven't studied the other side of things with any effort. I feel more and more that reality exists as a fractal, and any direction you focus upon yields its own profound truths. Time exists as a constellation of attention -- and this particular go around it happens to lie within the measurable, observable spectrum.

Disclaimer: I have a layman's understanding (at best) of astrophysics.

Couldn't this be explained by an orbiting planet colliding with another body and breaking apart? Couldn't this satisfy the number of "comets" required for the hypothesis?

I have a degree in physics... and this seems like as reasonable an explanation as any other to date. We know planets migrate, we know large collisions occur, which tend to be followed by periods of bombardment (e.g. Thea/Earth -> Moon, Jupiter from inner to outer system), so the observations, particularly coupled with the gradual but significant dimming, could correspond with Kessler syndrome on a stellar scale.

Actually, I say that, but they also address this in the paper - a planetary collision would result in a huge amount of excess heat - infrared - and there isn't any. So scratch that. Whatever did this is cold from our point of view.

I don't get it. Couldn't it have cooled down already and we're only seeing the junk?

Unlikely. The only place for thermal energy to escape is into deep space, in the form of infrared radiation. Given that the dimming has been large and recent, it would have to have been a recent collision - which would take millions of years to cool.

I see, very interesting. Thank you for the reply!

There is a thing called the Kardashev Scale[1], which is a way of measuring technological advancements of a civilization. According to the scale there are 3 levels of civilizations and we are not even at the 1st. I've done some reading on this before and the general assumption of many futurists and theoretical physicists is that our brain wouldn't even be able to comprehend what we'd see if we ever witnessed a civilization of the 3rd level. I know it's way out there, but couldn't this be the case here?

[1]: https://en.wikipedia.org/wiki/Kardashev_scale

Could there be something weird going on with the star itself? For example, could it be producing super large sunspots or something like that?

I suspect that fusion/fission models don't allow for the way it's being observed.

Possibly a new variety of variable star, like the Beta Cephi and slowly pulsating stars [1]? The article doesn't have any information as to what sort of spectrographs, etc have been taken.

[1] https://en.wikipedia.org/wiki/Slowly_pulsating_B-type_star

+1 for "Funky Star" hypothesis.

This seems just as probable/improbable as any other speculation, including (meme joke) "Aliens."

I'd be curious if anyone evaluated the fluctuations to look for a signal. If aliens had the technology, dimming a star might be a smart way to communicate with less advanced civilizations.

Well, when the frequency of your dimming spans across a century (and only for 20%).. you'll be long dead when the bit has flipped.

There are lots of ways to encode a signal. Perhaps there are very minor dimming a and brightenings that happens more frequently.

like a carrier wave in am radio?

Mr. Wright claims that these megastructures don't make sense with our technology, but perhaps even for these very advanced aliens this is not easy? Perhaps these are their pyramids? They may well be tossing immeasurable robotic efforts or genetically modified biological suffering at building these megastructures.

It's worth considering that this is something extraordinary even for this civilization that is far more advanced than we are. Rather than a hum-ho project for an extremely advanced species (or sentient AI).

This is probably a pyramid-scale project.

let's face it, this article was put out for the chance the publication could use the words 'alien megastructure' to grab some views.

I always wondered if perhaps a rocky planet broke apart. Could still be aliens or some kind of massive collision.

The first thing that comes to mind is that this is probably due to something like a giant dust cloud somewhere close to the star or close to us, and we are or it is moving into position behind it, leading to this dimming.

Reminds me of the beginning of "Pandora's Star" by Peter F. Hamilton. If you don't know him already, but you like Sci-Fi, you should definitely consider having a look at his work.

Can we get this title changed? It seems excessively click-baity while not making sense. If comets could explain it, it wouldn't be an 'alien megastructure' star, right?

To be fair, the SETI people kind of ruled out radio-emitting aliens as the source.

"Aliens did it" is still the worst explanation. It just happens that we ruled out all a lot of better ones.

To me it is in the same league as those "theories" that support intelligent design that run along the lines of "Well we can't prove God didn't do it" and Ancient Aliens theories where that manic guy with the crazy hair says the same stuff.

Filling in knowledge gaps with the the word "aliens" is a laughably childish approach to science in my opinion.

This line of reasoning is so frustrating.

There is no reason to believe that God(s) exist. Someone who claims that they do has the burden of proof.

There is also no reason to believe that we Earthlings have the universe all to ourselves. It is an extraordinary claim to suggest that we do. Someone who makes such a claim also bears the burden of proof.

The idea that gods and Type II civilizations are equally implausible is, to put it bluntly, ridiculous.

> Filling in knowledge gaps with the the word "aliens" is a laughably childish approach to science in my opinion.

You are talking about probability of life in the universe based on a tv show, replace aliens with "earth is round" and you will see how ridiculous it sounds.

> To be fair, the SETI people kind of ruled out radio-emitting aliens as the source.

That just means they're not aiming a tight radio beam directly at us. But I don't see why they'd be doing that anyway. Aliens that are not trying to talk to us are still a possibility.

I appreciate that the article referenced Bowie's "Space Oddity" and "Starman"

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