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Comment by rhcom2 | Hacker News Reader

> Despite widespread speculation, the possibility of the signals coming from an advanced alien civilization has been largely ruled out.

Anyone know how?

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Among other things, contemplate the energy requirements for producing a signal that we're picking up 3 billion light years away. Even if it's somewhat directional it's a huge energy output, as in "death of a small star" huge.

Physics has many unanswered questions, and we can't rule out the possibility to generate energy equivalent to the death of a small star. My point is not just a formal nitpick. Everything, all the stars, all the matter, all the energy is there. Many orders of magnitude more than what we are talking about of stuff was created at least once, and we don't know how. Why would one rule out that it can be repeated? Maybe it can be repeated in smaller scale.

You shouldn't completely rule it out, but you should apply occam's razor to try and guess the most likely cause for such an event. Looks like the scientists did that and largely ruled out this hypothesis. Of course as long as we don't figure out exactly what created this signal we can't be absolutely sure.

Rather than taking a position, being agnostic seems more appropriate to me.

We don't know. We don't know what physics may enable, we don't know if there's other life out there or what capabilities it might have.

I don't see any need for coming down on a particular side, nor any solid evidence for doing so.

You basically give up on science then. Maybe gravity doesn't work the way it does and it's just highly advanced aliens messing up with us. Maybe there's a teapot orbiting the sun between Earth and Mars. Maybe I'm actually an alien trying to confuse you so that you don't find the truth.

Extraordinary claims require extraordinary evidence and all that.

Nonsense. You make judgements based on the amount of evidence available. To simplify a bit, the more favourable evidence the more likely you think something is, and you make decisions accordingly.

My point was basically arguing that you should always factor in the known limitations of your current knowledge, whereby if you know there's limitations to the knowledge you can't just assume that the knowledge is representative of how things are.

> Extraordinary claims require extraordinary evidence and all that.

What part of being agnostic about something do you think involves believing extraordinary claims??

I see what you mean but unless you can argue otherwise it seems that the people who work on that stuff have "largely ruled out" this theory. I don't have enough knowledge or experience in astronomy to contradict them.

You're free to disagree of course but so far your argument sounds more like a nihilistic "you can never really know anything" which leads to a logical dead end.

So apparently one of the reasons it has been "largely ruled out" is the amount of power that would be required to generate the signal. Because we know that our knowledge of physics is not definitive, it is entirely possible that there are ways of exploiting physics that we aren't aware of that could produce such amounts of power. We also know that our knowledge of whether there's alien life, and, if there is, what their capabilities might be like, is very limited. We know that we know very little about what they might be able to do and why they might do it. Thus, it would be making a massive assumption to think that, just because we don't know how or why such a signal could be artificially generated, that therefore we can largely rule it out.

Thus, I believe the appropriate position is being agnostic. We don't know. If we learnt more then that could change, in either direction.

This argument is based on positive knowledge about the limits of what we currently know, not the nihilistic argument you reference.

A relatively-recent example that comes to mind. These days we know of many many planets outside of our solar system, but it wasn't long ago that we had not found any. I remember hearing a lot of people say that the fact that there was no evidence of such planets meant that there odds were very low. They were making the same mistake: of not factoring in the known limitations of the knowledge we had (i.e. we knew that the tools we had weren't good enough for spotting planets below a certain size/distance away from us), and assuming that the knowledge we had was representative of how things actually were.

That's fair I suppose. It's true that when you consider the universe at large the scale of everything is so mind numbing that it's hard to draw the line between the likely and the extravagant.

We don't really know anything!

We do understand a lot of things, and we have degrees of confidence in said understanding, and we have a scope where confidence is high.

That's all science can give us.

Ruled out = extremely low confidence, according to our current understanding.

It seems like if your civilisation spent millennia trying to contact anyone without response you might progress to harnessing a star as a communications beacon?

I'm sorry that nobody else in this thread seems to understand the meaning of the words "largely ruled out".

I also would like to know why that is. Not saying it's aliens just saying I'd like to know the reasoning.

Why would an alien civilization do this?

And I don't just mean, come up with something that maybe some really powerful but really stupid alien civilization might conceivably do in a silly science fiction book. Explain how this is the best use of their still-limited power.

Even the old standby "well maybe they're just incomprehensible and we can't understand them" doesn't really work here because when we're talking about "incomprehensible" aliens we don't usually mean that they're incomprehensible on account of being cosmically stupid and wasteful.

(I am speaking about what we actually have evidence for. If there's multiple exabytes of incredible data packed into this signal somehow we have no evidence for it. I like to distinguish very clearly between "things based on the evidence that we have" and "airy flights of fancy based on what might be hiding in the gaps", on the grounds that the latter is unbounded, so while they are fun in stories, in a way the very unlimited nature of the possible sets of speculations makes them uninteresting as an analysis of the real universe, all equally lost in the noise of all the other fantastic possibilities.)

I just thought "ruled out" makes it sound like they have some criteria for a "alien" signal vs natural.

Well, randomness (entropy of the singal etc) is a good criterion which doesn't require deciphering.

These "signals" have less entropy than normal, which is what is interesting about them, so we have to come up with additional criteria here.

Well, simple periodic/repeating signals occur all the time in nature -- so it has to be more advanced than that to consider it an actual message or "intelligence made".

Even if it was the Macarena beat it would hardly qualify as such.

A variation on Clarke's 3rd law is:

Any sufficiently advanced technology is indistinguishable from nature.

So the origin could be such an advanced intelligence that it looks natural.

Maybe because we already understand most of the physics required for space flight and the boring conclusion is that huge arrays of lasers are the most feasible way to accelerate an object to a fraction of light speed.

Sure we can dream about FTL, but the physics support for that is minimal at best.

I'm reasonably sure that hydrogen bombs are the most feasible way to accelerate an object to ~0.03c. We know how to build bombs, and concepts for big-shock-absorber-with-bomb-shute spaceships looked feasible with the tech from 1960.

Sure, but how about 0.2c? Carrying your fuel with you has some pretty serious limitations for anything short of a fair chunk of your mass being anti-matter.

However with the lasers you leave the fuel at home.

It appears to be few bytes. And probably not information.

Still, I think being confident about what a civilization capable of sending an intergalactic signal is doing is a bit much. Maybe some kid was bored (and was throwing neutron stars into a black hole).

There's also the possibility that FRB-s are artificial in its origin, but it's the byproduct of some technology we don't really grasp yet.

> Explain how this is the best use of their still-limited power

Weapon. I suppose you could ask the same question looking at our nuclear tests - why someone would waste so much energy in a single event? Maybe it's just remnants from their firing range?

Or an actual use of weapons.

Perhaps they're celebrating the failed attempt by anarchist revolutionaries to cause the emperors home star to go nova.

There you go.

Nice!

And that's probably genocide on a multi star system level. Good cause to celebrate.

>Explain how this is the best use of their still-limited power. Even the old standby "well maybe they're just incomprehensible and we can't understand them" doesn't really work here because when we're talking about "incomprehensible" aliens we don't usually mean that they're incomprehensible on account of being cosmically stupid and wasteful.

Sorry, where did the idea of "still-limited power" came from? Or the idea that they're power constrained enough for this to be "wasteful"?

"Things we have evidence for" also includes our lack of a definitive understanding of physics and our lack of understanding of what life does or doesn't exist out there. That needs to be taken into account. You can't just assume the positive knowledge you currently have is representative of how things actually are.

Probably because of the transmitting power involved, scaling it in favor of natural galaxy noise

I would guess mostly Occam's razor https://en.wikipedia.org/wiki/Occam%27s_razor

Darn, I don't want to discover the aliens now! We're much closer to meeting AGI which is kind-of like an alien intelligence for us.

we are aliens

"intelligence" cough cough

Laugh now, while you still can. There will be a time when our age will be seen like we see the stone age.

I laugh about IA that have intelligence. The time you are born is not funny, why laugh about this?

Turns out it was just episodes of The Alien Bachelor?

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