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Why should the orbital plane change?
Why would there be a period of 750 days if we see different objects every time anyway?
Why would there be a period of 750 days if we see different objects every time anyway?
KIC 8462852 (dipping again in March 2018)
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craigi
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mfb said:
Precession of the orbital plane could be caused by a non-uniform gravitational field surrounding the star.
Perhaps a gravitational non-uniformifty caused the centrifugal forces within the star if it has an angular momentum which became misaligned with that of the surrounding system.
mfb said:
I'm envisaging a thick ring of debris orbiting the star so that when the orbital plane aligns from the perspective of Earth that there is a high probability that some of that debris occludes the star.
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Coming from what?craigi said:
Centrifugal forces where acting on what?craigi said:
We know many systems where the stellar rotation axis is not aligned with the orbits of the planets. That doesn't matter - the oblateness of stars is a negligible effect, and relativistic effects are negligible as well.
craigi
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mfb said:
I did a quick search and there's a paper here from 2002, with calculations to give a guide on plausibility.
http://iopscience.iop.org/article/10.1086/324279/pdf
Their conclusion is that a precession period of hundreds of years could be observed. The system we're considering here would have a precession period of 4 years, if my theory is correct.
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The planetary orbits discussed there are very close to the star. The planets would have orbital periods of days, and show many periodic transits during a large time of the (very long) precession period.
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According to Bruce Gary, it is dimming again!
Currently 1% below its normal brightness.
There is some speculation that the time between the dips is a multiple of 24.2 days. That doesn't fit perfectly this time (25 days since the peak of the last dip), but it is still intriguing. It would mean a potential third dip around July 7th.
We might have a long period of 750 days, and then this strange 24.2 day pattern.
The May event lead to a lot of attention, so this time everyone is looking.
Currently 1% below its normal brightness.
There is some speculation that the time between the dips is a multiple of 24.2 days. That doesn't fit perfectly this time (25 days since the peak of the last dip), but it is still intriguing. It would mean a potential third dip around July 7th.
We might have a long period of 750 days, and then this strange 24.2 day pattern.
The May event lead to a lot of attention, so this time everyone is looking.
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newjerseyrunner
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Does 25 days after a 750 day cycle sound like it could be in a Lagrange point for the main object?
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The stable Lagrange points are 1/6 of an orbit ahead/behind, that doesn't fit. Two unstable points have the same phase angle and the last one is half an orbit away.
If I converted date formats correctly, then nearly all previous dips (over 1300 days) fit to a single 24.2 day pattern, but the recent two don't fit into that pattern, they are off by about a week. Only the difference between the dips fits roughly. But I could have made a mistake somewhere in the conversion.
If I converted date formats correctly, then nearly all previous dips (over 1300 days) fit to a single 24.2 day pattern, but the recent two don't fit into that pattern, they are off by about a week. Only the difference between the dips fits roughly. But I could have made a mistake somewhere in the conversion.
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We had something like a triple dip, with up to 2% dimming. It looks like the intensity is still below the normal one today, but the measurements are not so clear.
Here is the most recent light curve.
Here is the most recent light curve.
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Bruce Gary stopped his observations due to the weather, but others are still taking data. If the estimates are accurate, the star is still 0.5% below its normal luminosity.
Here is the most recent update.
57880 was May 7, July 29 is day 83 on the scale used in the image.
What started with a few very deep dips seems to become a mess of many shallow and long dips. Something that broke up and disperses over time?
Here is the most recent update.
57880 was May 7, July 29 is day 83 on the scale used in the image.
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Looks like a third dimming event started, currently nearly 1% below the nominal brightness.
Edit: I'll update the light curve once in a while. Current light curve from here.
Note that some older data points changed, as the analysis methods improve over time the estimates get more accurate.
It has been argued that the current dip series shows some similarity to the series of dips in 2013. Here are both overlaid, with the most recent update not yet in, but it fits to the next dip.
Edit: I'll update the light curve once in a while. Current light curve from here.
Note that some older data points changed, as the analysis methods improve over time the estimates get more accurate.
It has been argued that the current dip series shows some similarity to the series of dips in 2013. Here are both overlaid, with the most recent update not yet in, but it fits to the next dip.
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The third dimming phase seems to be over (updated light curve in the previous post).
Two publications have appeared.
Where Is the Flux Going? The Long-Term Photometric Variability of Boyajian's Star
They focus on the observed dimming trend, and they also find phases of brightening. Variations this large over a few years are uncommon. The Sun has a cycle of comparable length, but only ~0.1% variations.
Extinction and the Dimming of KIC 8462852
Confirming the dimming in several wavelength ranges.
Two publications have appeared.
Where Is the Flux Going? The Long-Term Photometric Variability of Boyajian's Star
They focus on the observed dimming trend, and they also find phases of brightening. Variations this large over a few years are uncommon. The Sun has a cycle of comparable length, but only ~0.1% variations.
Extinction and the Dimming of KIC 8462852
Confirming the dimming in several wavelength ranges.
Pdgenoa
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Two things. One: discussions of the phenomenon as being artificial ARE serious. Dismissing it and laughing it off is an emotional reaction - not a rational one or a scientific one. And frankly the behaviour from supposed professionals whenever the extraterrestrial hypothesis is brought up is juvenile.
Either you believe there's extraterrestrial life in the universe or you don't. You don't get to pick and choose when it's convenient to discuss as one of many possible explanations. Furthermore it's not anymore an extraordinary claim than any of the other theories offered that have exactly zero examples of ever occurring. At least the extraterrestrial explanation has one example of having happened before - us.
This doesn't mean it should be the primary hypothesis but it also doesn't mean it should be the last.
Second thing: if we're going to assume it's artificial then you're making a leap that their technology is far more advanced than where we are so assuming it's a Dyson sphere is ludicrous. The idea a technologically advanced species with the ability to conduct construction of things larger than planets for the purpose of putting up solar panels is laughable. The bottom line is that even if we had proof right now that these were artificial structures, to then think we could even fathom their purpose is a joke.
So far every conventional theory offered has flaws that kill the theory. That's why we keep coming back to the idea of them being artificial. Until proven otherwise it must remain one of the explanations. Equal to any of the others offered that also have never been seen before. So maybe we can grow up a little and start talking about the alien hypothesis seriously instead of laughing it off as not worthy of serious consideration. It is.
Either you believe there's extraterrestrial life in the universe or you don't. You don't get to pick and choose when it's convenient to discuss as one of many possible explanations. Furthermore it's not anymore an extraordinary claim than any of the other theories offered that have exactly zero examples of ever occurring. At least the extraterrestrial explanation has one example of having happened before - us.
This doesn't mean it should be the primary hypothesis but it also doesn't mean it should be the last.
Second thing: if we're going to assume it's artificial then you're making a leap that their technology is far more advanced than where we are so assuming it's a Dyson sphere is ludicrous. The idea a technologically advanced species with the ability to conduct construction of things larger than planets for the purpose of putting up solar panels is laughable. The bottom line is that even if we had proof right now that these were artificial structures, to then think we could even fathom their purpose is a joke.
So far every conventional theory offered has flaws that kill the theory. That's why we keep coming back to the idea of them being artificial. Until proven otherwise it must remain one of the explanations. Equal to any of the others offered that also have never been seen before. So maybe we can grow up a little and start talking about the alien hypothesis seriously instead of laughing it off as not worthy of serious consideration. It is.
nikkkom
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Pdgenoa said:
There are about 50 types of variable stars, of all kinds of behaviors - from stable millisecond pulses to irregular variations on 10 year timescales. With intrinsic as well as extrinsic causes.
There are exactly zero stars with known Dyson spheres around them. As well as zero known signals of any kind with clearly artificial origin.
This does not make artificial hypothesis "laughable", or course.
This does, however, make artificial hypothesis quite a bit more extraordinary than "well, we discovered yet another type of variable star, this time it's caused by natural phenomenon XYZ".
Pdgenoa
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Well I deviated from my main point a couple times but I was specifically trying to call out the cognitive dissonance (or outright double standard in some cases) of folks in the scientific community - and even people like Seth Shostak. They claim to believe the likelihood of extraterrestrial life to be an almost certainty - just "out there" somewhere. As it relates to humans and Earth they swing wildly in the direction of "never". Again, this is an emotional and actually conditioned response from "serious" scientists who should know better.nikkkom said:
When I talk about things never seen before I'm not talking about stars in general. Of course there are a thousand different variations of stars all with different characteristics and behaviors. Yet none of the examples we've found fit KIC 8462852. Every time humanity finds something we think is unique in the cosmos we find out it's not. Every time.
We used to think Earth was at the center of creation and unique, now we know there are countless planets. Then experts said Earth was special because we had water and now we know our own solar system has water everywhere - some of those worlds with more water than earth. Then it was gold or the position of our moon, plate tectonics and on and on. But over and over we find this is just how the universe works. So yes, we currently have no definitive proof of life outside Earth but everything in our science and observation of the universe should tell us that if you find one of something then there ARE going to be more. This is no longer a fringe way of thinking as most in the scientific community now believe this makes sense and fits our models of past discoveries.
Yet they still retain this disconnect. If you accept the idea that we cannot be unique and there must be extraterrestrial life then that must be one of the hypotheses until facts show otherwise. Not the most or least prominent, just one of them. That it's a biological hypothesis should make no difference. The star types you mentioned do not explain KIC 8462852 nor do many of the literally unprecedented other hypotheses that keep popping up.
I'm not making a case that it IS extraterrestrials because there's no proof of that. I am making the case that excluding it as one of the explanations is irrational if you accept there is likely to be other lifeforms in the cosmos.
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Pdgenoa said:
No need to assume a more advanced technology. The pyramids at Giza are visible from many kilometers away. A Winnebago is compact and harder to distinguish from background noise. You can hide a Winnebago in a forest. Earth 2017 has the technology to make/place a huge screen in orbit.
The Dyson sphere model does not apply to KIC 8462852. A Dyson sphere adsorbs the star's light and radiates the heat. If there is re-radiated heat it is below current detectable levels.
Physics forums is not professional. No one is paid to post here. (if you want to send money something could be arranged)Pdgenoa said:
The professional statements about KIC8462852 help to clarify what we know about "artificial phenomenon". A civilization building spaceships the size of Texas would remain unobserved. We might notice a nuclear war but only if we happen to be looking that way at that moment which is highly unlikely. If a civilization is advanced enough to develop efficient communications and a basic respect for its environment then it will remain undetectable by current human methods.
You can have a serious discussion about artificial phenomenon around Vega. Unlike KIC 8462852 you cannot rule out the Vega Dyson sphere. It could be dust that causes the infrared excess. Vega could have star spots similar to sunspots. Vega is only 25 light years away so detailed measurements are much easier than KIC 8462852.
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You cannot prove otherwise, that is the problem. If you assume advanced aliens, and assume we cannot understand their technology, then literally every observation is consistent with the "aliens" hypothesis.Pdgenoa said:
Something you cannot disprove is typically not considered a scientific hypothesis. While it will always be an option, we cannot test it. We can only see if there is a natural explanation that we can test - and if it fits, we should prefer this.
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mfb said:
That can lead to strange conclusions. Take for example the abundance of cherry trees and grass in the Washington D.C. area. Why would you prefer a natural explanation? This version seams more consistent with other branches of science:
Pdgenoa
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stefan r said:
We don't disagree over that. I've always thought the idea that if it's artificial then it's some form of Dyson sphere to be odd. If it's artificial then there's probably an endless list of things it could be built for. A local groups capital like Coruscant from Star Wars. An experiment too dangerous to do in an occupied system so it's been put around this one for safety (assuming there's no habitable planet in the system). Maybe a massive trading center for multiple species from local systems. Hell, it could be some humongous group of artificial hives for a bee or ant-like species. If you go the route of artificial phenomenon then to settle on solar collectors seems like a narrow way to think.
stefan r said:
I was referring to professionals generally, not here. Non-professionals or non scientists like most of us tend to mimic or at least be influenced by the way professional scientists and experts think and I believe it's damaging for them to mix their professional opinions with personal biases especially when they're in conflict as they are on this topic.
DaveC426913
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Sorry, let me see if I understand your stance.Pdgenoa said:
1] The scientific community is not taking an extraterrestrial origin hypothesis of the phenomenon seriously - and shame on them. This is a serious contender.
2] But if it were of extraterrestrial origin, then the reasons for making it that are being put forth are laughable - nay, a joke - certainly not to be taken seriously.
Do I have your stance correct?
Seems to me, your argument unintentionally reduces to: there's no plausible reason why ET would build such a thing, therefore, there's no plausible reason why ET should be a serious hypothesis. But I don't think that's where you meant to go with that.
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Pdgenoa
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mfb said:
We can test whether or not it fits natural phenomenon up to a point but then if it's something never observed before we can only test the hypothesis by comparing it with things we do know. This has happened multiple times with this star and so far in each case the hypothesis has to be downgraded or dismissed because of one or more inconsistencies that make it untenable.
The thing is we *can* do the same thing if the hypothesis is that it's artificial. We have thousands of years observing and creating artificial things. We know what the characteristics are that distinguish between artificial and natural. This *is* something that can be tested. A good example is the IR observations. If this were debris from cometary or planetary collisions there would be clear IR readings to back it up. There weren't and we've mostly moved past those explanations. As were able to refine our observations we should be able to determine if the shapes and behaviours conform closer to what we know to be natural or artificial.
Even if it starts to emerge as fitting an artificial profile rather than a natural one I think it's unlikely we'd ever know it's purpose.
Regardless of which it turns out to be, at this point it will be an exciting and apparently unprecedented discovery.
Pdgenoa
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I think I've been pretty clear that it should only be a contender - no more or less serious than any other unsubstantiated hypothesis - and then only if that person has publicly expressed a belief that extraterrestrial life is likely. If someone thinks we're unique and alone that's perfectly their right and I think it should he respected. Either way I think it's reasonable to expect consistency.DaveC426913 said:
On the second one, yes, if you're going to entertain the idea it's artificial then at least recognize there many artificial things it could be. It would be like someone hearing a noise in their backyard and not knowing if it was a twig falling from a branch or an animal scurrying around declared that if it's an animal then it must he a Thickwood Badger. It would be absurd to be that specific when so little is known. Same here.
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Same thing, as we cannot test unnatural explanations if we assume we cannot understand advanced aliens.stefan r said:
Can you give an example of possible observations that would rule out alien influence?Pdgenoa said:
We don't even have to go to other stars. Can you rule out that aliens assembled Pluto? It is a silly idea - but there is no way to rule it out experimentally. So either we always add "aliens did it" as hypothesis everywhere - or we start with the idea that aliens are always the last option after everything else has been ruled out. And we are far away from "everything else has been ruled out" for KIC. We are at "the obvious explanations don't work, we need more data".
Pdgenoa
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You're conflating being able to understand advanced aliens with being able to determine if something is artificial and I agreed that understanding their purpose or motivation isn't likely to be known but we can know if something is artificial if it's within our own experience. A species that could or would build Pluto and make it look natural is obviously beyond our comprehension and beyond our ability to determine but if a species is technologically advanced enough to build things that are clearly not natural - like Dyson spheres or interstellar ships or solar system sized particle accelerators or death stars then those are things we can check assuming we can observe them in enough detail to see they're not natural. Whether that be determining shapes that don't occur naturally to transmissions to energy signatures or light signatures that don't conform to the natural spectrum to signatures of artificial materials.mfb said:
You can take anything to an extreme and make it sound any way you want if your goal is to just argue so it should go without saying that when I say we can test if things are artificial I'm referring to testing within the range of both our experience and our ability. Testing if a natural looking planet is artificial is both beyond our experience and our ability to test. Testing if it's an artificial shape or gives off light in a way that indicates an artificial material is not.
You repeat the Seth Shostak talking point that aliens should always be the last explanation. Why? Should an extraterrestrial explanation be behind a cometary swarm on a magnitude never observed much less hypothesized and if put forth as a possibility before KIC 8462852 would have been ridiculed as preposterous? If the answer is yes why? Because at least we know there ARE cometary swarms? Well, we also know there are technologically capable species - us. Why is one more acceptable than the other?
The reaction to throw an extraterrestrial explanation behind even the most outlandish "natural" explanation - and there have been a few with this star - is an emotional and societal bias - not a scientific one.
Pdgenoa said:
Utter nonsense. Seeking natural explanations before artificial explanations is entirely consistent with science. In the entire history of astronomy, and science in general, there has never been a single thing explained by extraterrestrial life. Ever. On the other hand, there have been thousands upon thousands of verified natural explanations for phenomena ranging from mundane to ones that were (and some that still are) almost incomprehensible beyond belief. The push to accept an extraterrestrial explanation as a serious contender is so premature at this time that I struggle to even find the words to describe it. Perhaps "Absolute and utter nonsense" is sufficient.
Pdgenoa said:
On the contrary, it's exactly the opposite. The push to include an extraterrestrial explanation as a serious contender is the emotional one. We know comets, asteroids, dust, and other things which could occlude the star's light exists. We know that there are stellar effects that can reduce a star's output. We know that combinations of the above can do odd, unexpected things. And we also know that there have been undiscovered natural explanations in the past that, when discovered, perfectly explained an previously unexplained phenomenon. It is entirely reasonable to seek nearly any natural explanation over an extraterrestrial one at this time.
Pdgenoa
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To those reading this thread take note of the tone of my posts and the tone of this one: personal, emotional. This person has also done what a few other replies have done and characterize my assertion that the extraterrestrial hypothesis be a "serious" contender. I've only ever said it should be a contender and taken seriously. Where you put it on the list of possible explanations is entirely subjective. In addition not once have I suggested or even implied that the extraterrestrial hypothesis "is" the explanation or should in any way be preferred.Drakkith said:
This reply makes my point better than I've been able that there's a societal bias whenever the subject of extraterrestrials (in any context) comes up. It's not this person or anyone else's fault since it's been pushed in our culture for over fifty years. The impulse to shrug off, ridicule, dismiss, and in the case of the scientific community looked down on with derision. We have generations that have been marinated in the stereotypes of people taking aliens as serious as being crackpots, eccentric and unhinged. While it's pretty easy to understand where this bias came from it has no business in the scientific community.
We used to have similar ideas about psychiatrists and those who went to them.
As long as people keep insisting I'm saying something I'm not I'll take this as an offramp. I've made my point. People can agree or not but at this point I'm just repeating myself.
nikkkom
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Drakkith said:
I think you are a bit too harsh. Extraterrestrial explanation is a "serious" contenter (it _is_ possible, it's not insane or totally stupid). It's just quite far off from being among leading ones.
jerromyjon
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I would like to add my two cents that if some intelligent race were to get beyond a golden record with greetings in various languages launched out of the solar system what would be the next logical step? I think the next step would be to cause an astronomical event that had no other explanation... just my two cents.Pdgenoa said:
nikkkom
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jerromyjon said:
Well, if "astronomical event that had no other explanation" would be a radio/IR/visible signal which spells out prime numbers from 2 to 1013, in binary, _THAT_ would be *very likely* a signal generated by extraterrestrial aliens.
A star with semi-random fluctuations of brightness is not even close.
jerromyjon
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And how much energy would be required to get "that signal" out across any serious distance?nikkkom said:
Semi-random sounds like possibly not random... but not regular...nikkkom said: