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Comment by natch | Hacker News Reader

I think the really significant term in the Drake equation is the question of time overlap between our civilization and any civilizations in other star systems.

In other words, the likelihood that they either lived before or (will live) after us is overwhelming, since the time scale of the universe is so vast compared to the time scale (with our one known example) of a civilization.

Our timeline is like the blink of an eye, compared to the age of the universe. Very unlikely that nearby blinks would happen at exactly the same time, even with a 11,000+ multiplier.

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As far as I remember, the likelihood of a technological civilization forming before us is rather small.

Basically we live in the goldilocks zone of our galaxy.

Stars further towards the center are being constantly bombarded by types of radiation that make the formation of structured self-replicators almost impossible.Entropy rules.

Stars further towards the rim have not yet gone through enough generations to produce the abundant heavier elements needed.

We live in the zone that is both old enough and stable enough for technologically adept life to thrive, and we turned up on the scene about as early as we could.

So we are probably just one of the first.

We are a late by random 100000000 years since the point of as early as we could, which is a pretty big error.

> So we are probably just one of the first.

We don't really have any way to know that. Considering that there may be as many stars in the sky as grains of sand on Earth, there are many many unknowns.

For another example we don't know for sure if our universe is the only one and it's entirely possible that everything that could ever happen plays out in real time across and infinite number of universes. We don't have any way to physically measure that possibility yet. We only have mathematical theories.

Similar to how Copernicus proposed the heliocentric model, maybe our universe is not even the center of existence?

It is humbling to imagine.

All those stars you see in the night sky? That’s an astronomical waste of energy. No technological energy limited civilization would let that waste continue, entirely unhindered.

The fact that we don’t see the light of stars, or whole galaxies replaced by dim infrared waste heat emissions means either (1) new physics will point to free energy solutions that circumvent thermodynamic laws [unlikely], or (2) we are the first.

or 3) the assumption that advanced civilizations consume more energy is wrong.

Or 4) - interstellar mega-engineering is impossible, or essentially impossible, or it's ROI is negative.

Which seems to be the most likely explanation to me.

The really advanced civilizations developed their technology just enough so they could build a really safe and reliable Matrix to live out their lives in.

They would still consume their local stars to extract and store the energy so their matrix can survive for trillions of years, rather than a few million or billion.

We may not have the capability to build a Dyson cloud around our own star (yet), but we do already have the technology. You could do so with 21st century tech, and the ROI would be positive.

Even then, there are two issues:

1. disassembling the stars to make them live a thousand times longer

2. it only takes one expansionist civilisation seeking interstellar exponential growth — even if 99.9% of civilisations are quiet, that's just 3 digits of the 22-digit number of stars in the observable universe.

> disassembling the stars to make them live a thousand times longer

Why would they do that when there are insane amounts of start with billions of years of life ahead of them. What purpose would that serve at this point in time?

Even though the numbers are too big for humans to feel them out, the bigger one is bigger than the smaller one.

Because trillions is bigger than billions.

That was (1) new physics. Because otherwise, entropy is a bitch.

Already today, having passed peak-child a few years ago, we can see that there are futures possible where humanity doesn't grow. I.e. humanity might be fine advancing with a fixed amount of power.

In that case, the stars are not 'waste'.

Historically, this idea of growth as method for advance is only a few centuries old. It's not hard to see its end as efficiency keeps increasing.

That'll change once we solve disease and aging.

Or just maybe civilizations advanced enough for Kardyshev level 2 engineering feel no need for exponential expansion. Fermi paradox is essentially Malthusianism extended to outer space.

If nothing else, eventually civilizations are confronted by questions (in math, say) that can only be solved by extremely large amounts of computation. We know there must ultimately be succinctly stateable problems that cannot be solved easily; this follows from the undecidability of math.

It could well be that harnessing the energy of one star is sufficient for most of that. This is very hard to detect for an observer.

Going K3 to 100 billion stars of the galaxy "only" gives you a 10^11 constant factor speedup at enormous expense and with Amdahl's penalty at galactic scales.

Astrophysicists tell us that star formation will continue for 100 trillion years.

We are indeed among the first simply because of the sheer amount of time left ahead of us vs. behind us. It's basic math. We are at 0.014% of the expected duration of this universe.

There are almost endless modes where life could develop in much more different and harsher conditions. More radiation? Well stronger magnetic fields for those. Too much space debris randomly popping into star systems? Have a big vacuum cleaner like Jupiter or two (or five). Not that common but if you have 500 billion stars many unprobable things can and will happen.

Life as we see here on Earth is extremely adaptable. Give it harsh environment, and unless its too much immediately it will adapt and actually take advantage out of it (ie too much radiation? well we can mutate to our ideal desired form even quicker).

Also, 1 billion years doesn't mean much in this cosmic scale. But imagine if civilization like ours had that much headstart. Well, you can't imagine, and neither can I in same way homo erectus couldn't imagine CERN particle accelerator or black holes.

It's an even bigger gap than that.

Homo Erectus takes us back around 100 million years. A billion years gets us to very simple multicellular life which can't do imagination at all. Or logic. Or thinking. Or creativity. Or much of anything else.

So... a billion year old civ is going to have very fundamental abilities which are completely beyond our comprehension.

It's like Dunning Kruger on a cosmic scale. Except that with Dunning Kruger there's usually some potential to learn a way out of ignorance.

Here there isn't. Not only can we not do it, or understand why we need to do it, we can't see - never mind reach - the first rung of it.

> So... a billion year old civ is going to have very fundamental abilities which are completely beyond our comprehension.

Maybe not. There's no evidence that species can continually adapt and evolve to higher levels of intelligence. Humans are already hitting limits for how much we can think, figure out, etc.

But by that same token, maybe so. Humans aren't exactly the cream of the crop when it comes to higher critical thinking and emotional intelligence.

Is there any biological research that takes a look at a single or sequence of species maintaining civilizations lasting x amount of years?

Natural evolution may have its limits, but we don't yet know how much we can improve by artificial means.

We will have the technology to alter the DNA to increase our intelligence significantly. There are limits, but I don't think it is likely that human beings are at the peak of what is biological possible.

- When we reach the biological limit, we may extend ourselves by merging with technology. Our brains might be connected to a computing device that amplifies our capabilities. It may be so seamless that when answering a question, you won't notice if the knowledge was stored in your physical brain or retrieved from a central archive.

>- When we reach the biological limit, we may extend ourselves by merging with technology.

In the near term, I just wish they'd figure out how to make better mechanical parts for humans. Our natural joints suck, particularly knees and ankles. It really shouldn't be that hard to make mechanical replacements for various parts of the human body.

> Humans are already hitting limits for how much we can think, figure out, etc.

There is zero evidence of this.

What would that mean?

Once our intelligence encompassed communication then it began growing culturally. I.e. we are able to treat math and engineering as no biggies, despite humans needing millennia to realize "nothing" could be a number called "zero".

It's fair to say the 21st century shows no signs of intelligence slowing down. We keep finding ways to think more simply but more effectively.

>Homo Erectus takes us back around 100 million years.

Huh? Where did you get that crazy number? 100M years ago was the age of the dinosaurs. Homo erectus was around somewhere between 250K and 1.6M years ago.

He probably meant 100 thousand years.

> and we turned up on the scene about as early as we could.

> So we are probably just one of the first.

Those two sentences don't really mix. We have evidence that points to life forming basically immediately once the conditions are right. That means that for us to be the first, nowhere else in the galaxy and universe could have had the conditions. That just seems incredibly unlikely. Even in our own Solar System, other bodies like Mars had the conditions for life before Earth did.

On top of that, Earth itself had the potential for intelligent life long before humans came around. But instead of evolving some overgrown monkeys, it evolved some overgrown birds who were too selfish and shortsighted to work together and develop a space program and watch out for large asteroids. They were mostly wiped out because of this, and it took 65 million years for another selfish and shortsighted group of animals to evolve and become dominant. Unlike the last ones, they developed a space program, but it's not really enough to handle threatening asteroids yet, but they're busy destroying themselves and their environment in other ways, so it may be moot. It might take Earth 3 tries to finally evolve a sentient species that becomes a spacefaring civilization.

With you until the last sentence. Why would the "third try" not just be dinosaurs again? Same for the 4th, 5th an subsequent "attempts". The fact that the second try got further than the first does not mean that the 3rd will get further than the second.

In fact, given that most of the easily accessible coal and oil deposits will have been used up it might even be much more difficult for a subsequent species to get as far as humanity has. (Although that might be balanced a bit by lots of the metal ore being pre-mined and near the surface)

> ... most of the easily accessible coal and oil deposits will have been used up .

There'll be plenty of time for nature to compact and bury much of the biomass from the previous sentience attempts.

Depends. Most of the current coal deposits were from before fungi and bacteria evolved the ability to digest lignins and similar compounds. Now that they can do that, no more (or at least much less) coal deposits are being created.

Some ongoing research into this timeline: https://www.science.org/content/article/some-dinos-may-have-...

Orcas very likely have human adjacent intelligence and evolved earlier than humans. They arrived several to tens of million years before humans, as far as I can tell. Orcas are simply constrained by their environment as far as technological development goes.

Or it means that the conditions are not persistent -- life originates in a stellar system either immediately, or not at all.

> We have evidence that points to life forming basically immediately once the conditions are right.

What's the evidence for this? Not asking rhetorically, I'm curious and want to read more.

I have picked it up from a variety of resources. One is the Origins of Life course on Complexity Explorer: https://www.complexityexplorer.org/courses/155-origins-of-li...

Basically, as my understanding goes, life is effectively as old as the Earth is. As soon as it cooled down after forming and had liquid oceans, life started, which happened just a few hundred million years after Earth formed.

There is the book Every Life is on Fire as well, describing how life began to dissipate heat in the environment of molecules in water being heated. That seems to imply life will quickly start in such conditions. (Note: I don't strongly recommend the book, as it has a lot of religious stuff in it and honestly isn't that well written, and I have mainly learned about the author's theory elsewhere.)

The other part of that overlap is whether they are using radio signals. I think a lot about the fact that there may very well be other ways of wireless signal transmission that don’t require radio (gravitational waves are one example though I’m not sure if I would expect those to be used for data transmission).

200 years ago no one knew radio communications were possible. We still don’t understand quantum entanglement. Our understanding of physics, while more advanced than the past, is still clearly limited. We may find that there are better ways than radio to transmit data, and this could explain why our radio surveys have so far not detected extraterrestrial data packets (as far as we can tell).

Even for radio we went from blasting megawatts into space to keeping a lot of it in the atmosphere. We ourselves are proof that radio's a poor way to detect aliens and our reduction in radio emissions was a natural progression of our technology, not an attempt to hide.

What's more telling for those in the neighborhood is the strange amounts of O2 in our atmosphere's spectral lines. That came to be long before us, it will persist long beyond us and it's a clear indicator of a non-geological process that might intrigue aliens.

Spectral lines may be telling about conditions suitable for certain type of life. But as per some theories life itself may be quite abundant in universe, but mostly primitive equivalents of stromatolites so it may not be that interesting for aliens to keep checking every single planet for such life in whole galaxy, especially if speed of light is absolute speed barrier.

One other thing I came up with on a long evening walk recently was to check for gravity fields. If you have all bigger pieces of matter mapped well within galaxy, and you grok all physical laws there are, you should be able to predict movements and gravity fields for billions of years with high precision. Kind of make a complex checksum of given galaxy. If this changes for no predicted reason, bingo you just have a very strong candidate of life evolving enough to escape its planet and start moving big chunks of matter around (think big asteroids or changing orbit of planet slightly to ie counter some natural catastrophe like greenhouse effect / ice age, or living near slowly dying star).

Obviously this is way ahead of us and maybe even not possible, just a fun thought. But if you start space mining company by any chance in the future, please don't move matter around too much.

Hmm it's a nice idea but gravity is such a weak force that it seems like it would be hard to move significant enough bits of matter around for it to be detectable. If they were going around annihilating whole stars and clusters then maybe.

Or if they built a stellar engine. https://en.wikipedia.org/wiki/Stellar_engine

Or even if there isn’t new physics for wireless transmission, it seems likely that a civilization living on a single planet would keep increasing the efficiency of their communications until very little radio leaks out.

Even further, advances in coding schemes make data look increasingly like noise to the outside observer. Think of the readability of a text file versus the same file after zip compression

or encryption

Like we have. Moved a lot from radio over to the internet. Highly focused communication.

Still that uses a lot of radio signals (Wi-Fi)

Good luck detecting a Wi-Fi access point from orbit, let alone the next starsystem over.

> In other words, the likelihood that they either lived before or (will live) after us is overwhelming, since the time scale of the universe is so vast

Not sure this logic makes a whole lot of sense.

Imagine a universe similar to ours, but with a lifetime cut short by a doomsday device. Would you expect any difference in the likelihood that mirror humanity coincides with another alien civilisation?

Independent of other factors, adding more time doesn't really reduce the number of civilisations existing at any one time, it gives more time for civilisations to emerge.

Your logic suggests there is a fixed number of civilisations to distribute evenly across the lifetime of the universe. Now, the number of civilisations may be limited by usable energy for life to consume rather than time - but in that case I'd expect civilisations to cluster at the beginning of time when entropy is low.

Edit: in fact Drake didn't actually include any term for age of the universe in his equation.

I think it reduces the lower bound for how many civilisations we'd expect to exist, from our N=1 example? 1 civilisation in (say) 1 million years would suggest they're more common than 1 civilisation in 13.7 billion years?

Tricky, but maybe.

But I think I was imprecise with my language. By "age" I meant the total lifetime of the universe as a place with planets capable of supporting life, rather than the amount of time between the big bang and now.

> I think the really significant term in the Drake equation is the question of time overlap between our civilization and any civilizations in other star systems.

    universe begins
      0.1 Gy
    first stars
      9 Gy
    our solar system begins
      0.5 Gy or less
    early life
      3.5 Gy
    complex, multicellular, macroscopic life
      0.5 Gy
    sentient, intelligent life

I think the important delays are the 9 Gy and the 3.5 Gy. (Gy = billion years)

9 Gy: After first stars, how many generations do you need of large stars, synthesizing heavy elements, going supernova and shooting the heavy elements around, contributing to the condensation of new stars (now with some heavy elements to begin with), until you cal form solar systems and planets like ours, with enough iron and heavier elements to make life chemically possible. Do you need to wait this full 9 billion years, before planets with the chemical composition of Earth appear, or did they already appear sooner?

3.5 Gy: How long does it "usually" take from early microbial life, for evolution to develop complex multicellular life? In our case it took 3.5 billion years, but are we among the fastest, or the slowest?

Reminds me of the failing of the k-nearest neighbor algorithm. It works extremely well in low dimensionality, but given high dimensionality, its astoundingly bad. As you scale up the space and number of dimensions, the distances between individual chunks of data gets so large its hard to draw meaningful conclusions.

I dunno I've done a lot of high-dim knn that were quite pragmatically useful

https://en.wikipedia.org/wiki/Curse_of_dimensionality

Maybe we're talking at cross purposes; what I mean is that PCA+KNN or other tricks mean that for high dim and large amounts of data you can get useful results; with the enlarged view of KNN as "anything where the last step is KNN" your statement that it's "astoundingly bad" is wrong. But for the narrow view of just KNN then sure cod applies.

How high is high?

I had a professor who would jokingly say "It's lonely in 128 dimensions"

Right, nobody's at those other dimensions at the same time as you are.

I think the most significant term in the Drake equation is the one chosen by users of it to hang themselves on this week. It's an equation that pumps out a number between zero and bazillions dependent on imaginations towards a situation that is nevertheless a paradox. The only thing that can be said right now is that it's perhaps likely that the number is >1.

It's >1 over what volume? The galaxy? The observable universe? All the unreachable volumes of space beyond that in our universe? All the many-worlds branches of this universe?

“Perhaps likely >1” - in whatever volume the Drake equation covers. Until it goes to a certainty of >1 in the volume we can explore then it’s basically =1.

I don’t believe the current absence of evidence is much of a useful data point. Until we have scoured other star systems and the rest of the galaxy turning over rocks we can’t really generate useful empirical data to fill in the numbers on the Drake equation. The paradox of “where is everybody” has myriad solutions.

A mistake definitely lies in philosophers and theorists believing their sci-fi ideas are better than anyone else’s. Certainly not useful data towards writing papers that form a proof of any number as a solution. It’s hard to prove an absence, particularly when there’s a universe of empirical data that can be potentially gathered but hasn’t been yet.

If I was a betting person, I’d put a stake on there being life somewhere like Enceladus. Even life from earth in the form of fungal spores has existed for long enough to escape and float around the galaxy - they’ve had a few hundred million years. Life here could have also landed from elsewhere as easily as terrestrial abiogenesis. There’s just so much we don’t know and haven’t tested. Not being able to pull radio signals out of the noise proves nothing given the mere seventy years of attempts.

I’m not sure about many worlds, and how that could be proved either to be a useful part of science. By the same token, in an infinite universe, then literally every single possibility and permutation is being tried, so in that case, yeah there’s life everywhere. Including a universe where I’m out being the first human to find it rather than writing this comment.

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