
Comets can't explain weird 'alien megastructure' star after all - aburan28
https://www.newscientist.com/article/dn28786-comets-cant-explain-weird-alien-megastructure-star-after-all
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sandworm101
>>> “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.

~~~
Sharlin
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.

~~~
Almaviva
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.

~~~
dragonwriter
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.

~~~
Almaviva
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.

~~~
marvin
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.

~~~
Sharlin
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.

~~~
Houshalter
>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.

~~~
Sharlin
"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.

~~~
Houshalter
>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.

~~~
Sharlin
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.

------
kordless
> “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."

~~~
WiseWeasel
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.

~~~
idlewords
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.

~~~
sandworm101
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!)

~~~
jschwartzi
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.

~~~
sandworm101
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.

------
tzs
> “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.

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.

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

~~~
tzs
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.

~~~
andrewflnr
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.

------
onestone
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.

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

------
natch
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.

~~~
nonbel
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.

~~~
Sanddancer
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.

------
JackFr
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.

~~~
cnp
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.

------
spyrosk
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?

~~~
madaxe_again
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.

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

~~~
madaxe_again
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.

------
sakopov
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](https://en.wikipedia.org/wiki/Kardashev_scale)

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

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

~~~
Sanddancer
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](https://en.wikipedia.org/wiki/Slowly_pulsating_B-type_star)

------
mrfusion
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.

~~~
xgbi
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.

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

~~~
hidroto
like a carrier wave in am radio?

------
BuckRogers
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.

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

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

------
mangeletti
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.

------
pilif
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.

------
matthewbauer
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?

------
rbanffy
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.

~~~
n0us
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.

~~~
CamperBob2
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.

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

