Astronomers may have found giant alien 'megastructures' orbiting star near the Milky

[stevebowers]

So if this advanced xenosophonts really exist around this star and if they decided to investigate the galaxy and send self-replicating von Neumann probes to the nearest stars in the year 535 CE. How long would it take for one of the copies of these original probes to arrive here?

Good question.
By a very strange coincidence, KIC 8462852 is at about the same distance from Earth as the To'ul'h home planet is in OA. Terragen probes reached To'ul'h Prime in 3831 AT, so if they had technology equivalent to the OA terrans we could expect them in about 2000 years or so; a bit faster if they had Current Era tech.

Using replicating probes this would take a bit longer, since the infrastructure to create each new wave of probes has to be constructed from scratch in the new systems. But as Carl Sagan realised many decades ago, the speed at which a wave of replicators spreads depends on how far each probe travels before replicating. If the probes only travel ten light-years or so before replicating, then they will take a lot longer to get here than if they travel 100 light years, or a thousand. Note that a replicating swarm that travels long distances before replicating will be spread very thinly, unless each swarm member replicates a very large number of times (which is not impossible, of course).

[stevebowers]

After discussing this star on the Cosmoquest board, I realise that I don't really think that these observations are an indication of alien megastructures, or of a partial Dyson sphere.

As we observe more and more systems in detail, we are going to see more and more unexpected natural phenomena; these are exciting times in many ways. But just because we can't immediately explain any particular set of observations doesn't mean that we should be using 'alien megastructures' as a default explanation for any unidentified data. There are going to be a lot of really weird systems up there, even if life and/or intelligent life is not implicated.

As far as alien megastructures and life-signs are concerned, we mustn't forget that they would be alien, so need not conform to any of our preconceptions. An unconstrained factor like alien life and alien civilisation will lead to many possible false positive detections, as well as many possibilities for false negatives as well.

[Rynn]

Agreed, the reality is we don't know what this is but that doesn't suggest it's artificial in any way. Absence of evidence is not evidence of absence. The predictions about what an intelligent species is likely to do, how a matrioshka would look etc are interesting but often seem quant. Expecting aliens or future societies to conform to that sort of setup is like any other prediction of the past; often steeped in current biases.

[Matterplay1]

After discussing this star on the Cosmoquest board, I realise that I don't really think that these observations are an indication of alien megastructures, or of a partial Dyson sphere.

As we observe more and more systems in detail, we are going to see more and more unexpected natural phenomena; these are exciting times in many ways. But just because we can't immediately explain any particular set of observations doesn't mean that we should be using 'alien megastructures' as a default explanation for any unidentified data. There are going to be a lot of really weird systems up there, even if life and/or intelligent life is not implicated.

As far as alien megastructures and life-signs are concerned, we mustn't forget that they would be alien, so need not conform to any of our preconceptions. An unconstrained factor like alien life and alien civilisation will lead to many possible false positive detections, as well as many possibilities for false negatives as well.

Turning back to the OA setting for a minute, this might make things tricky for astronomers in a civilization comparable to ours that is with the light-cone of the Terragens, unless they catch something unambiguous such as communications beam that they can decipher. Some of the theories they might invent to explain what they observe, without invoking aliens, could be quite interestingly wrong...

[stevebowers]

One possibility that has crossed my mind is a naturally evolved Dyson swarm. We have naturally evolved photosynthetic swarms on Earth - the phytoplankton in the sea form a swarm of sorts, as do the land plants and forests. If a system has enough material in orbit to support a photosynthetic swarm, then it could evolve into a self-regulating macroscopic structure that would be detectable with relatively primitive instruments. The most fertile location for a swarm of this kind could be a protoplanetary disk or relatively young system full of dust and comets.

[Stardust]

I agree it'd be a great idea for an alien ecosystem, but if a proto-panetary disk with lots of dust would be the ideal breeding grounds for such a thing this system could be problematic. Last I heard, Tabby's Star is older and wouldn't have much in the way of planetary disks, asteroids, or dust/gas clouds.

[stevebowers]

The recent media buzz has started to generate comedy. Here's a comic strip about a Dyson swarm, called Derelict Orbital Reflector Devices
http://dord.horse/

Why were we given sentience?
So we could annoy each other, apparently.

[PortalHunter]

Dude there are still 2x10^13 of us in orbit

[giulio]

As far as alien megastructures and life-signs are concerned, we mustn't forget that they would be alien, so need not conform to any of our preconceptions. An unconstrained factor like alien life and alien civilisation will lead to many possible false positive detections, as well as many possibilities for false negatives as well.

In fact, the idea of megastructures sounds 20th century to me. Perhaps very advanced alien civilization don't _need_ megastructures because they have long ago transitioned to upload civilizations that can thrive in small computational nodes with a limited footprint. Also, perhaps they would use smarter communication means than radio waves.

Having said that, I hope to be proven wrong by the detection of a signal from megastructure builders around KIC 8462852.

[stevebowers]

Yes, an alien civilisation could miniaturise until it reaches some sort of physical limit- quite how small that might be would be constrained by their technology (they may not develop magmatter, for instance, which in the real universe may not be feasible).

However once this lower limit of size is reached, the civilisation could still expand into some sort of Dyson swarm, one which includes both tiny, dense processors and large power-collection systems and databases. In fact, this is more-or-less the condition of most Panvirtuality swarms in OA - each star colonised by the Panvirts holds an microcosm of staggering complexity.

I suspect, but can't prove, that any swarm that held so much data would be fairly disinterested in the rest of the real universe - unless, of course the real universe posed some kind of threat.