Fermi Paradox thread; aliens welcome

[JoeP]

We at are not convinced by Signals from space aliens? and question the elderly nutter who says Space Aliens are Real!!

So what's our preferred resolution of the Fermi Paradox?

[Dragar]

Intelligent life must be really, really rare.

That's all I can conclude. You can come up with wacky explanations ("Aliens are shy... aliens destroy themselves...aliens prefer not to interfere with undeveloped peoples...") but you have to make that explanation for every possible alien race. I think, sadly, it's much more likely that we're the only intelligent species in the galaxy.

[JoeP]

But the "superpredator" hypothesis covers nearly every possible alien race with one explanation. The exceptions being ones not yet intelligent enough to hide all their traces - they pop up often enough to feed the superpredator (who may feed every million years or so) but not often enough that's there's ever more than one or two at a time.

[Dragar]

Well, I'd argue that intelligent alien races are pretty rare if something is eating them.

[JoeP]

Yes, numbers existing would be rare, but intelligent civilisations could still be a common thing to develop, not special or unique. Which is what most of this argument is about for many people, I think.

And eating isn't the only possibility. It could be a swarm of self-replicating nanobots preprogrammed by the first intelligence to arise, twelve billion years ago, to protect themselves (it all went horribly wrong). Or a galactic AI whose only imperative is preventing competition from arising. (It's busy wondering if there is intelligent life in other galaxies.)

[Dragar]

A hungry entity out there (because that is the best of the manifestations the explanation can take) also dovetails nicely in the Doomsday Argument. We can't be that far from being eaten ourselves.

[ceptimus]

Swarms of self-replicating robots (nano or otherwise) if they existed, would already be here and on any other planet capable of supporting life. Even at pedestrian speeds (in space terms) it would only take a few hundred million years for such devices to spread over the entire galaxy.

I suppose you could argue that they are here, hiding, till we develop some threshold level of technology that triggers them, but I find that hard to believe.

I also don't believe that any aliens that are clever enough to navigate across interstellar space would bother being a super predator on other intelligent species.

We may be capable of launching self replicating robots ourselves in the next hundred years or so - then after, say, a billion years, robots originating from Earth designs will be everywhere. A billion years isn't much compared to the age of the galaxy, so it seems that either something will stop us doing this seemingly achievable thing, or we'll be the first (or one of the very first) species to do it.

[JoeP]

Originally Posted by ceptimus

but I find that hard to believe.

I also don't believe that

Are you arguing from personal incredulity™?

I find it hard to believe that we are alone. Touché.

However, I find it very easy to believe that independently-evolved life will be very different from Earth's, and independently-arisen intelligence could be unrecognisable, even in its constructions and communications.

[ceptimus]

Originally Posted by JoeP

Are you arguing from personal incredulity™?

Yeah, when some explanation seems to me to be incredibly unlikely and/or stupid, I'm prepared to take the risk of calling it.

Here's an example: the Telegraph's Science Editor, calmly reporting on something that is just bat shit crazy and ridiculous. She should be sacked.

Inflatable ‘space elevator’ invented by scientists - Telegraph

[lpetrich]

Second Nexus on Twitter: "We've arranged the top 15 explanations for why haven't we made alien contact yet. http://t.co/wFBab8lmCR http://t.co/letCQ81Jjv"
linking to
The Fermi Paradox , Expanded | Second Nexus

Here's a written-out version of that flowchart:


p(life) no: No Life
p(life) yes: p(complex life)

p(complex life) no: "alien algae"
p(complex life) yes: p(intelligent life)

p(intelligent life) no: "alien dinosaurs"
p(intelligent life) yes: p(technology)

p(technology) no: late start for life and intelligence (we could be the first)
p(technology) yes: p(kill)

p(kill) no: late filter: self-destruction (wars, ecological trouble, resource trouble)
p(kill) yes: p(Ba'ku)

p(Ba'ku) no: no desire to create a high-tech civilization (the Ba’ku in Star Trek: Insurrection)
p(Ba'Ku) yes: p(hiding)

p(hiding) no: Scaredy-Cat (hiding themselves to avoid being detected)
p(hiding) yes: p(us): are they aware of us?

p(us) no: p(general): are they sending out general sorts of signals like we are?

p(general) no: p(detect at distance): are we able to detect their technology from a distance?

p(detect at distance) no: invisible habitats like inside a Dyson sphere
p(detect at distance) yes: p(right places): are we looking in the right places?

p(right places) no: unusual locations like inside black holes
p(right places) yes: *** Contact! ***

p(general) yes: p(detect): can we detect and recognize their signals?

p(detect) no: Universe of Babel (we don't know how to detect or recognize the signals)
P(detect) yes: *** Contact! ***

p(us) yes: p(able to visit): are they able to visit us?

p(able to visit) no: p(signal): have they tried signaling us?

p(signal) no: p(watch) are they watching us?

p(watch) no: they don't find us interesting for whatever reason (made of meat, etc.)
p(watch) yes: p(good): do we have a capability for good?

p(good) yes: Earth Zoo (until we are ready)
p(good) no: Whack-a-mole (to keep us contained)

p(signal) yes: p(detect)

p(able to visit) yes: p(here now): are they here now?

p(here now) no: Garden World (seeded and left) -- or Government Coverup
p(here now) yes: p(you one of them): are you one of them?

p(you one of them) no: Here and Hiding -- or Government Coverup
p(you one of them) yes: *** Call Me ***

[JoeP]

That's a good article, and not just because it quotes the same xkcd comic.

[JoeP]

We have not given enough consideration in this thread to the possibility that Gamma-ray bursts (GRBs) explain the Fermi paradox. Even though the following is from Dec 2014, before this thread:

Phys. Rev. Lett. 113, 231102 (2014) - Possible Role of Gamma Ray Bursts on Life Extinction in the Universe
Did Deadly Gamma-Ray Burst Cause a Mass Extinction on Earth?
Gamma-ray bursts are a real threat to life - CERN Courier

Basically, there's a 50% chance that a major GRB affected Earth within the last 500,000,000 years. Some suggest a GRB was responsible for the Ordovician extinction 450,000,000 years ago.

A GRB doesn't wipe out life instantly - it depletes the ozone layer via chain chemical reactions, and regular cosmic rays do the rest.

So, the frequency of GRBs could be high enough to "clean up" or reset life frequently enough to mean that there are few or no intelligent forms out there. In smaller galaxies than ours, esp galaxies formed in the first 5 billion years of the universe, there could be no possibility of complex life.

This theory has a name: Neocatastrophism - Wikipedia, the free encyclopedia

But look ahead, as well as to the past. A GRB could wipe us out. Shouldn't we do something about this? Dyson Sphere - Freethought Forum

[davidm]

Yes, there have been aliens

vs.

Fancy math can’t make aliens real

[davidm]

Originally Posted by JoeP

Are you arguing from personal incredulity™?

I find it hard to believe that we are alone. Touché.

However, I find it very easy to believe that independently-evolved life will be very different from Earth's, and independently-arisen intelligence could be unrecognisable, even in its constructions and communications.

Highly relevant to the above

[JoeP]

Originally Posted by davidm

Yes, there have been aliens

...

By ignoring the question of how long technological civilisations last, the "near certainty" this article calculates that we aren't the first does nothing to tell us whether we are alone. And makes the survival question even more significant: if trillions of technological civilisations have come about, but we can't detect signs of even one, does that mean they are get extinguished quickly and so will we?

[davidm]

Originally Posted by JoeP

By ignoring the question of how long technological civilisations last, the "near certainty" this article calculates that we aren't the first does nothing to tell us whether we are alone. And makes the survival question even more significant: if trillions of technological civilisations have come about, but we can't detect signs of even one, does that mean they are get extinguished quickly and so will we?

Well, see the rebuttal article from Atlantic, and most especially see the book chapter by Norman Swartz linked above, which is an extended analysis of why that ant cartoon you posted is probably exactly right.

[JoeP]

Originally Posted by davidm

and most especially see the book chapter by Norman Swartz linked above, which is an extended analysis of why that ant cartoon you posted is probably exactly right.

I imagined it would ... it is currently tldr

[JoeP]

OK I read it. I think it proves that philosophers and human beings cannot communicate in the same language. Sorry, I mean that alien civilisations are likely to communicate in ways we would have a minuscule chance of understanding - even to behave and think in ways we wouldn't understand.

But ruling out understanding (which I question, see below) in no way means we would not be able to detect things - which could be buildings or machines or waste products, not just attempts at communication - which show evidence of technological civilisation. I'm thinking of entropy (and the idea comes from old science fiction but there's some more recent research which I need to read up on).

And once we decide that some physical phenomenon requires intelligence, there'll be no limit to the amount of effort we put into trying to understand it. However different these forms of intelligence are, something will be achieved, some sequence of major insights into minor details eventually leading to understanding.

[Ari]

One issue I have with the self replicating explorer robot hypothesis is it assumes it's somehow advantageous for intelligent life to build and send out a massive wave of robots to every single star, gathering little useful information while consuming both the life's resources and future resources potentially destroying budding life on planets as they go.

It's possible there are explorer robots out there and our solar system didn't meet the proper exploration criteria and got checked off the list from a flyby while going to a more interesting looking system.

Given breaking energies it would be more efficient to send out a bunch of flyby probes who then note any planet of interest to send the slower lander vehicles. Similar to our pluto flyby, the first most likely human probe to another star will be a string of small probes each grabbing a small amount of data as they zip by.

[ceptimus]

No. The whole point of the robots being self-replicating means that you only have to send out a few, or even just one. Providing each robot makes, on average, more than one new robot before it dies, then the number of robots grows exponentially till there are sufficient to explore every corner of the galaxy.

[Ari]

Yes but the robots would need to stop, mine material, fabricate base metals/polymers/fuel then relaunch a new probe, even on a tiny scale this takes a lot of resources not only slowing the exploration down but potentially spending resources useful by future generation ships and colonies. It would suck if intelligent life decided to expand beyond their solar system only to discover their options are limited due to an infestation of their own robots.

Even if that happened, the slowing down part is resource intensive and would probably only happen at the end of the probe's life, so it's possible a probe zipped through our solar system a million years ago and cataloged the planets on it's way to another star.

[JoeP]

Originally Posted by Ari

Yes but the robots would need to stop, mine material, ....

Not all would need to stop, if they travel in a swarm. At least two but why not thousands. Swing by a star system - send 100 robots into the system, gravitational braking (OK I made that up), half go on courses to monitor and transmit, half go into the system's oort cloud to mine and replicate. Some of the freshly minted robots head out to continue their 5 billion year mission to explore strange new worlds and convert them into paperclips.

[JoeP]

Originally Posted by Ari

One issue I have with the self replicating explorer robot hypothesis is it assumes it's somehow advantageous for intelligent life to build and send out a massive wave of robots to every single star ...

What such robots end up doing may be unrelated to any advantages intelligent life may have thought of - they could have got out of hand.

Originally Posted by JoeP

It could be a swarm of self-replicating nanobots preprogrammed by the first intelligence to arise, twelve billion years ago, to protect themselves (it all went horribly wrong).

[Vivisectus]

Originally Posted by davidm

Highly relevant to the above

There is no inevitableness in our having an arithmetic, in our having a geometry (many of them in fact), in our having calculus, in our having physics, chemistry, or biology. There is no inevitableness, either, in our formulating theories of personhood, in our codifying logics, in our exploring the bases of morality, or in our wondering about the validity of our senses. Science and philosophy both – like music – are the products of creative imagination. There was no more inevitability in humankind's enjoying Newtonian physics than there was in its being the beneficiary of Beethoven's creative genius.

This seems to ignore the fact that both science and music are not just made up out of personal achievements. They are part of disciplines that work cumulatively. Both Beethoven and Newton stood on the shoulders of giants. It may not be guaranteed that bursts of genius occur. But because we are an information-transmitting species now, these breakthroughs are now kept and built on.

And it is this information-transmitting between people can be said to have started much earlier than this article stated.

[JoeP]

Originally Posted by Vivisectus

It may not be guaranteed that bursts of genius occur.

Misread as thrusts of genius ... ... :newtonthrust:

After all, the SI unit of thrust is the newton.