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).
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.
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.
>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.
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.