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Comment by StreakyCobra | Hacker News Reader

«But that would be an extraordinary coincidence, if that happened so recently, only a few millennia before humans developed the tech to loft a telescope into space. That’s a narrow band of time, cosmically speaking.

After all, this light pattern doesn’t show up anywhere else, across 150,000 stars. We know that something strange is going on out there.»

It would also be an extraordinary coincidence if we find another planet with life on it, so quickly after humans started to look for it. 150'000 stars is a narrow band of universe, cosmically speaking.

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If this is life, in a life-as-we-know-it sense, then it tells us that there are two species within a couple of thousand light years in about the same stage of evolution; which suggests that life's going to be everywhere.

Assuming one civilisation within a sphere 1000ly in diameter, that makes 16000 in our galaxy alone!

This also assumes life follows some statistical laws at a cosmic scale :)

We know that stars follow statistical laws on a cosmic scale, because we can see them, and have mapped them. So it's a reasonable assumption that life which forms round stars, like us, will be distributed the same way as the stars themselves.

It's worth noting that KIC 8462852 is an F3 star very similar to our own, which is a G2.

Reasonable assumptions lead us to lots of incorrect conclusions, but I take your point :)

Well, it's also possible that there's something special about the Milky Way in particular that makes it just a teensy bit more life-friendly, right?

It might be a bit early to worry about life densities in other galaxies.

This conclusion leads as straight to the Fermi Paradox https://en.wikipedia.org/wiki/Fermi_paradox

If this is life, in a life-as-we-know-it sense

It's much weirder than that; after all, there's been life on Earth for at least 3Bn years, but space-going life for only the past 57 of them! Stack it all up: if this is some sort of life-created megastructure then it's not just evidence of life, but of presumptively-multicellular tool-building life that can get off its planet and survive in an intensely hostile environment that it didn't coevolve with.

With an estimated 100Bn stars in our own galaxy alone, this would suggest we can expect to see on the order of a million interplanetary-capable life forms in the process of carrying out mega-engineering projects, and yet none of them have come calling on us? Fermi Paradox calls bullshit.

The Fermi Paradox is predicated on the principle that aliens would actually want to come here. I'm not sure this is a valid assumption.

For a hot and fast civilisation like us to exist for serious amounts of time in space, it's going to have to adapt to living in space --- because, as you say, it's intensely hostile. One of the key adaptations is to stop being hot and fast. If you can live on small energy budgets you're way more likely to survive. If you live slowly then travel becomes much easier, as well as costing less.

But if you become a cold and slow civilisation, inner solar systems aren't going to be very hospitable --- hot, radioactive, space is so bent that travel is enormously difficult, everything's at the bottom of cripplingly expensive gravity wells... why bother? The gas giants are rich, but are even more expensive (to get from low orbit around one of the moons of Jupiter to low orbit around another takes about 10 km/s. You can launch from the surface of Earth for that). But further out... the Kuiper and Oort clouds are peaceful, cheap, hospitable, and chock full of light elements with interesting (if slow) chemistry.

Estimates of the Oort cloud density predict that there'll be a 20km body every 30 light seconds or so, and that there's about five Earth masses in Sol's Oort cloud alone. And Oort clouds of neighbouring stars overlap...

So I'm expecting any successful civilisation to start colonising the spaces between the stars, rather than the star systems themselves.

In this model, our own solar system could already be colonised, and we'd never know. They'd probably have noticed our radio transmissions by now, but it may not have occurred to them to answer yet. They may not bother; if we survive long enough to adapt to space, we'll be out there soon. Or they may not be able, depending on their energy budget. Or maybe they are, and we just haven't noticed. (New Horizons has a 12W transmitter and we would have to be looking in exactly the right direction to spot it. And it's way closer than the Oort Cloud.)

Of course, this doesn't explain why our hypothetical civilisation has built a hypothetical megastructure around this star. I wouldn't know why they'd want to do that (except for noting in passing that interstellar travel for hot-and-fast creatures like us basically requires a Dyson sphere for the energy requirements).

I'm planning a book. Can you tell?

The Fermi paradox only requires that some alien species would have both the desire and capacity for stellar engineering.

So I'm expecting any successful civilisation to start colonising the spaces between the stars, rather than the star systems themselves.

Before you start writing your book, you might want to familiarize yourself with the prior art in the field: start with the short story "Swarm" by Bruce Sterling, then the novel "Permanence" by Karl Schroeder, "Blindsight" by Peter Watts, and maybe "Diaspora" by Greg Egan. That's assuming that by "planning a book" you're thinking in terms of fiction rather than SETI-oriented non-fic, but even if you're writing non-fic it's worth noting that we SF authors have been all over the topic for decades. (As for non-fic, the prior art goes all the way back to J. D. Bernal's "The World, The Flesh, and The Devil", if not further: I don't read Russian but I gather Nikolai Federov wrote on the subject, as did Konstantin Tsiolkovsky.)

I've read all of those! (I actually discovered Karl Schroeder from your blog; for which I thank you. I gather _Lockstep_ addresses the same subject, but haven't read it yet.) Although they're very much focused on going substellar objects, e.g. brown dwarves or dark giants, while I'm thinking of the vastly more common asteroidal bodies. It's not a subject I've seen addressed very often.

Here's the paper that crystallised the idea for me:

http://arxiv.org/pdf/1201.2687v1.pdf

Also, yes, fiction --- I'm not enough of a scholar for non-fic.

>>Fermi Paradox calls bullshit.

Fermi Paradox assumes ET would like to communicate, or be allowed to be detected in some way.

That's a very big assumption, given how many unknown unknowns exist out there.

As you say we have only been lofting stuff into space for 57 years, and sending out radio waves etc. for a few decades longer than that/ There are still some uncontacted tribes on the earth despite our relatively rapid global population growth...I'm not sure why you think more advanced alien civilizations would be in a rush to get in contact the (cosmic) minute they noticed earth's lights coming on. After 500 or 1000 years, yeah.

It's also possible that more advanced civilizations are paying attention but are waiting for us to get over our kill-it-with-fire stage in response to large-scale visitation :)

It all depends on how common live and consequently intelligent life is, we currently have absolutely no clue.

http://i.imgur.com/tRKbi15.png

The actual light graph looks a hell of a lot more like a comet breakup to me than a swarm of solar collectors around the star.

Unless life is relatively common. In that case it's not so odd.

Life might be common but intelligent life might be rare. Of all the countless species on this planet, only a handful (if even) have developed the ability to control fire and construct tools; considering how expensive it is on the organism, it might not be a generally successful evolutionary mutation. We might be an extraordinarily rare aberration.

It's a good point. Dinosaurs were on Earth for a very very long time. We really have no idea how rare it is for life to evolve in such a way as to become highly intelligent.

Makes you wonder if Dinosaurs would have evolved to the point of becoming some sort of highly intelligent reptilian species similar to us. That is, if they hadn't been destroyed. :D

There's also species' such as Parrots and Dolphins that are both considered to be quite intelligent. So maybe intelligence is a fore-gone conclusion and that final step that "snowballs" their intelligence is just another roll of the dice occurrence.

Makes you wonder if Dinosaurs would have evolved to the point of becoming some sort of highly intelligent reptilian species similar to us.

You're half right. Dinosaurs have evolved[1][2] to become highly intelligent[3], but not reptilian and only similar to us in the sense that they are the only other species that makes hooks to catch food[4].

[1] "The scientific consensus is that birds are a group of theropod dinosaurs that evolved during the Mesozoic Era." https://en.wikipedia.org/wiki/Origin_of_birds

[2] https://xkcd.com/1211/

[3] http://www.scientificamerican.com/article/crows-understand-a...

[4] http://io9.com/the-mysterious-tool-making-culture-shared-by-...

And it's not just intelligent life, either, when you think about it; it requires intelligible life. It doesn't matter how clever the individual is; without a relatively efficient means of bundling up abstractions and hypotheticals and so on and transferring them from one individual to another, progress is slow, limited and contextually bound. There is something special about language - a serialization scheme for thought - that sets it apart from mere communication, and there is no reason to assume that it's an inevitable natural consequence of individual intelligence. Call it another term in the Drake equation.

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