Speculations that this is a sign of imminent supernova are - highly speculative.

Quite.  It is a variable star, and we don't know if (or even expect, really) obvious changes in its brightness would correspond to changes in its core fusion processes.  I liken it to all the buzz that happens in the media whenever Yellowstone hiccups.  It has probably had hiccups since before modern humans came around, and we don't know what it does right before it goes off, or even if it does anything noticeable at all.

But it is neat that such a prominent star in the sky is now much dimmer than we've been used to.  The stars aren't constant.

Added:  Good news though is that, unlike Yellowstone, when Betelgeuse finally does blow up it will be spectacular and not dangerous.  At least to us.

Let's all place bets- what will explode first- Betelgeuse or Eta Carinae?  I predict that we will all either be 6 ft under by then or we will all reside in immortal artificial bodies by then!

I predict that we will all either be 6 ft under by then or we will all reside in immortal artificial bodies by then!

Chances are good that if we'd survive up until then, those stars would have been diffused by us by some means along the lines of star-lifting.

I think Eta Carinae already exploded and we're just waiting the GRB to reach us 

hose stars would have been diffused by us by some means along the lines of star-lifting.

I have already considered whether the decrease in the brightness of Betelgeuse could not have been caused by a kind of star-lifting.
Not the 'normal' method, in which several new stars would be created next to Betelgeuse, we would be able to see that. Instead, the star matter would be absorbed by one or more wormholes and the new stars would be formed elsewhere.
(Possibly we could notice a change in diameter. Maybe we should take a closer look?)

I have already considered whether the decrease in the brightness of Betelgeuse could not have been caused by a kind of star-lifting.

That sounds pretty ridiculous.  Even if you manage to focus the stellar mass quite a bit, it will still be a pretty thin soup to harvest.  Betelgeuse is practically made up of vacuum.  The density of Betelgeuse is 0.000000012 g/cm³.  On average, so less at shallow depths.   The average density is less than 1/100,000th the density of air at sea level on Earth, or roughly the pressure above Earth where "space" begins.  You need fairly decent equipment to achieve that kind of vacuum in a lab on Earth.

I have already considered whether the decrease in the brightness of Betelgeuse could not have been caused by a kind of star-lifting.

That sounds pretty ridiculous.  Even if you manage to focus the stellar mass quite a bit, it will still be a pretty thin soup to harvest.  Betelgeuse is practically made up of vacuum.  The density of Betelgeuse is 0.000000012 g/cm³.  On average, so less at shallow depths.   The average density is less than 1/100,000th the density of air at sea level on Earth, or roughly the pressure above Earth where "space" begins.  You need fairly decent equipment to achieve that kind of vacuum in a lab on Earth.

Yeah, as a resource, Betelgeuse and other stars similar to it are pretty useless. The only reason I can think of as to why a large, advanced interstellar-civilization would bother using star-sheparding technology on it is if they wanted to nullify the effects of it's age, which is a pretty huge task considering the complexities involved. I say large interstellar civilization because they would be the only ones who'd have a real need to physically diffuse (or more conveniently, remove altogether - which of course we're NOT seeing) the star from their premises, and of course have the resources to do so. A smaller interstellar species (or nearby interplanetary civilization) would just construct a sun-shield around their solar-system facilities and ride out Betelgeuse's explosion, should it come to that. The latter method is just more efficient and easier to make.

Even if the outer sheaths of Betelgeuse are very thin, the core inside must inevitably be very solid. That is why the wormholes are positioned very close to the star core! (The high temperature probably won't harm the wormholes.)
Why do the aliens do this? They are doing this to save us!
We may have miscalculated, and Betegeuze explosion can do us harm.
(Of course they don't want to reveal themselves yet because we're not ready for them yet.)
(Just a thought. )

(Possibly we could notice a change in diameter. Maybe we should take a closer look?)

Its size fluctuates naturally, like most giant stars.

I have already considered whether the decrease in the brightness of Betelgeuse could not have been caused by a kind of star-lifting.

That sounds pretty ridiculous.  Even if you manage to focus the stellar mass quite a bit, it will still be a pretty thin soup to harvest.  Betelgeuse is practically made up of vacuum.  The density of Betelgeuse is 0.000000012 g/cm³.  On average, so less at shallow depths.   The average density is less than 1/100,000th the density of air at sea level on Earth, or roughly the pressure above Earth where "space" begins.  You need fairly decent equipment to achieve that kind of vacuum in a lab on Earth.

Yeah, as a resource, Betelgeuse and other stars similar to it are pretty useless. The only reason I can think of as to why a large, advanced interstellar-civilization would bother using star-sheparding technology on it is if they wanted to nullify the effects of it's age, which is a pretty huge task considering the complexities involved. I say large interstellar civilization because they would be the only ones who'd have a real need to physically diffuse (or more conveniently, remove altogether - which of course we're NOT seeing) the star from their premises, and of course have the resources to do so. A smaller interstellar species (or nearby interplanetary civilization) would just construct a sun-shield around their solar-system facilities and ride out Betelgeuse's explosion, should it come to that. The latter method is just more efficient and easier to make.

Isn't there some weird star out there which seems to show variations that haven't been explained by natural means?  I forget its name....

Isn't there some weird star out there which seems to show variations that haven't been explained by natural means?  I forget its name....

Do you mean 'KIC 8462852' (Tabby's Star)?
Sometimes it gets darker, sometimes brighter, in more or less regular intervals.
(A Dyson's sphere will probably be built there. But it is not yet finished, so these light fluctuations. )

(Of course they don't want to reveal themselves yet because we're not ready for them yet.)
(Just a thought. )

Aye, it's a fun thought. Other danger stars could be experiencing the same treatment near us!

Isn't there some weird star out there which seems to show variations that haven't been explained by natural means?  I forget its name....

It's been pretty much disproved as a candidate for a partial Dyson swarm around a star. Although their odds aren't much better, there are other candidates that are more interesting:

[youtube]DcuSNnuv4RI[/youtube]
As I said though, their odds of being extraterrestrial activity are still pretty slim, and it's far more likely that these were just super-flares of M-class stars observed during the telescope's scan.

The fluctuations in brightness around 'KIC 8462852' could possibly also be caused by dust clouds caused by intensive asteroid mining. Environmental pollution.

Isn't there some weird star out there which seems to show variations that haven't been explained by natural means?  I forget its name....

There are so many stars out there that there will also be some stars behaving in unusual ways.

The universe is big and extremely rare events happen all the time.  Consider this: In some star system out there, in some galaxy, two planets are colliding - right now as I type this.  And two other planets are also colliding when you read this.

Exactly. It is in fact thought that the Tabby's Star fluctuations are caused by a disintegrating planet. There was a fairly statistically-insignificant chance of us actually viewing that as it happened, but it just goes to show how busy the universe is.

It is in fact thought that the Tabby's Star fluctuations are caused by a disintegrating planet.

They are definitely related to dust and not some alien megastructure (due to wavelength dependence of the dimming which indicates scattering by particles with sizes comparable to visible wavelengths).  But not from a disintegrating planet or moon, or a violent collision in an asteroid belt.  Dust produced in those ways would be warm and produce a clear infrared excess, but no significant infrared excess is observed.  So the more likely explanation is a colder source of dust farther from the star.

The universe is big and extremely rare events happen all the time.

That reminds me.  In an older version of Space Engine I came across this planet with two suns, in the middle of a double solar eclipse.  And I just thought "Wow. Statistically, this must actually be happening out there somewhere in the real universe."
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