Do you think any aliens exist in the universe?

[Jokodo]

Economic growth is constrained only by the continued availability of larger numbers, and doesn’t necessarily imply increasing use of space or resources; You can achieve economic growth with fixed population and resources, by turning your resources into things that are more valuable than they were previously.

Are you saying that you can have endless economic growth without using more space and resources? BTW that's another reason to use other planets and stars....

No, that's no reason at all to use other planets and stars. If you can have endless economic growth without using more space and resources and/or a thriving, healthy civilisation that's not built on an imperative of economic growth, then there is hope for us. If a stagnant supply of space and resources implies a stagnant civilisation, in every bad way you can interpret this, then that's exactly what we're doomed to.

What do you think of the Kardashev scale I mentioned in post #54? Is the increased energy use it involves a good thing? (like how our large scale of technological civilization allowed a man on the Moon, etc)

Using other stars and planets doesn't change the equation in either case. At best it delays the inevitable no more than a few centuries.

The galaxy is about 100,000 light years across.... wouldn't timescales of more than a few centuries be involved?

Sure, there could be a rim of recently settled worlds where growth still happens, and that send out colonising ships to the virgin worlds beyond. The reality for 99% of humanity (a figure that would be growing over time) would however be one of a finite and constant supply of resources and space, just as if we'd all stayed on earth all along. And that's the state of affairs that would install itself within centuries, a couple millennia at best.

 

[Jokodo]

And trillions of years before hitting that wall, we'd hit another wall: the one where our demands grow faster than our supply of space and stars, and we start to experience scarcity on the scale as if we'd stayed on earth in the very finite bubble of space accessible by then. There's this pesky little thing called c, and the funny fact that exponential growth is, well, exponential, while cubic growth isn't.

If we move into space at a constant speed in all directions at once, we'll be adding 700% to our available space in year 2. In year 11, we'll only be adding 33%, and in year 302, it'll be less than 1%. Whatever growth rate of space and resource use you deem necessary, we'll soon drop below it.

If you are travelling at the speed of light it would take at least 50,000 years to reach the limits of our galaxy

An what would the growth rate of the space occupied by the human race be? Remember, expanding in all directions, the space grows in proportion to t^3. By the year 49,999, we can hypothetically reach a volume of 4/3 * pi * 49,999ly^3 - that's 5,235673603×10¹⁴ cubic lightyears. With the same formula, by the year 50,000 we've reached 5,235987756×10¹⁴ cubic lightyears. This ratio can be simplified as (50,000/49,000)³. With either method, that's a growth rate of 0.006% For all practical purposes, humanity will have reached stagnation, even if there's still some movement at the rims.

 

[excreationist]

If you are travelling at the speed of light it would take at least 50,000 years to reach the limits of our galaxy

An what would the growth rate of the space occupied by the human race be? Remember, expanding in all directions, the space grows in proportion to t^3. By the year 49,999, we can hypothetically reach a volume of 4/3 * pi * 49,999ly^3 - that's 5,235673603×10¹⁴ cubic lightyears. With the same formula, by the year 50,000 we've reached 5,235987756×10¹⁴ cubic lightyears. That's a growth rate of 0.006% For all practical purposes, humanity will have reached stagnation, even if there's still some movement at the rims.

But then there are huge numbers of other galaxies. I guess it is like life filling up the carrying capacity of a continent. At least it wasn't stagnant for a while - like it would be if they never left the solar system.
As far as what they'd be up to - they could be making huge computers - even filling up a whole galaxy -

Matrioshka brain

A Matrioshka brain is a megastructure in space based on the Dyson sphere, of immense computational capacity. It ranges in size from an asteroid to an entire universe, where it can hold the energy of trillions of stars to drive insane computational power that can run simulations of an entire...

kardashev.fandom.com

Purposes for these could be to create simulated realities

 

[excreationist]

I have no use for a self-replicating interstellar space probe. I have nowhere to store it, and no plan to ever use one, nor any idea who would be daft enough to buy one from me, if I was ever daft enough to buy one from you. But if it’s free…

Those probes could tell you which, if any, of the solar systems in our galaxy have life..... they could use networks of probes to send the messages back. I at least would be interested in exactly how many of the solar systems have life.

 

[Jokodo]

If you are travelling at the speed of light it would take at least 50,000 years to reach the limits of our galaxy

An what would the growth rate of the space occupied by the human race be? Remember, expanding in all directions, the space grows in proportion to t^3. By the year 49,999, we can hypothetically reach a volume of 4/3 * pi * 49,999ly^3 - that's 5,235673603×10¹⁴ cubic lightyears. With the same formula, by the year 50,000 we've reached 5,235987756×10¹⁴ cubic lightyears. That's a growth rate of 0.006% For all practical purposes, humanity will have reached stagnation, even if there's still some movement at the rims.

But then there are huge numbers of other galaxies. I guess it is like life filling up the carrying capacity of a continent. At least it wasn't stagnant for a while

Yes. For a few centuries. What good is that?

 

[excreationist]

But then there are huge numbers of other galaxies. I guess it is like life filling up the carrying capacity of a continent. At least it wasn't stagnant for a while

Yes. For a few centuries. What good is that?

It would take billions of years to reach the farthest galaxies.... a civilization that big is impressive..... though I'm not sure what it could achieve other than being able to make a huge number of simulated realities....

 

[Jokodo]

But then there are huge numbers of other galaxies. I guess it is like life filling up the carrying capacity of a continent. At least it wasn't stagnant for a while

Yes. For a few centuries. What good is that?

It would take billions of years to reach the farthest galaxies....

trillions, more likely, assuming it is even possible.

It would, however, only be centuries before stagnation would become the norm for the human race. What good is it for the people of earth, or of a near-earth spacer world, to know that out there, thousands, millions, or billions of light years away, there might still be some frontier worlds?

I don't think "excreationist would find it imressive" is a good enough reason to engage in an endeavor that would consume a significant portion of humanity's resources.

 

[bilby]

I have no use for a self-replicating interstellar space probe. I have nowhere to store it, and no plan to ever use one, nor any idea who would be daft enough to buy one from me, if I was ever daft enough to buy one from you. But if it’s free…

Those probes could tell you which, if any, of the solar systems in our galaxy have life..... they could use networks of probes to send the messages back. I at least would be interested in exactly how many of the solar systems have life.

No, they couldn’t.

Perhaps they could tell our great great great great grandchildren these things; I am not confident that they will care as much as you or I though.

You know what kids are like; They’ll be too busy with their heads stuck in their iPhone 32,487,692,631s, or complaining that they’re stuck with this clapped out old 32,487,692,629, and that if their parents don’t care that they’re embarrassed by their crappy old phones, why should they worry about some ancient ancestors and their stupid ancient space probes.

 

[Jokodo]

The nearest large galaxy is the Andromeda galaxy at 2.5 million light years away. There are some small galaxies en route, but their combined size is just a fraction of our own galaxies. Taking two and a half million years to double our population by reaching the next similar sized galaxy comes out as a growth factor of 10^(log(2)÷2 500 000). Expressed as a percentage growth rate over the entire period, that's less than 0.00003% per year.

Colonising other galaxies to maintain growth just shows a lack of understanding of exponential processes.

 

[Elixir]

Do I think aliens exist anywhere …

If they do, doesn’t that make us their aliens?

 

[Jarhyn]

I don't believe growth is essential. I believe growth will happen if it's practical.

I agree. But there’s nothing practical about interstellar travel. Shit, we are only just beginning to be able to spot Earth sized exoplanets. We don’t yet even know where we might be able to attempt to survive if we could get there, much less have the ability to go there and make the attempt.

Well, my thought on interstellar travel is "paint some asteroids with some vacuum and radiation tolerant spores, maybe coat it with a few coats of thermally resistant primers, maybe tuck some inside the rock, and toss the lot at a neighboring system or galaxy as hard as possible."

We would have to get really good at modifying DNA so that you could program a multi-part ecosystem to emerge from just that, and particularly good at modifying multistage life processes so that the spore itself, rather than producing a fungus, produces a whole ecosystem from which some engineered stage of human or human-like thing will emerge.

I would imagine it being something like the model imagined in the movie "Prometheus". Of course we would need to test the strategy out, but we could seed the universe with humans and human-compatible ecosystems, assuming we could get a strong enough understanding of multistage life processes to build such a biological bootstrap + terraforming system.

You could potentially code in everything you would want that process to discover somewhere, hidden in the mess.

It will take a million years just to get where it's going... As if we don't have time to wait a hundred thousand years for them to find the rock they crawled out from under (quite literally) and figure out how to read it...

Maybe we'll still be here, maybe we'll exist some other way. Either way, this is how I expect alien life to first appear: crawling out from under a rock that makes landfall.

In fact it's not far off from the plot of the movie Evolution.

 

[pood]

It’s really weird, this idea we are going to colonize the solar system and then the galaxy and perhaps the rest of the universe.

It’s unwarranted techno-hubris, and plenty fall for it, not only charlatans like Musk but truly bright people like Stephen Hawking.

Musk want to send five million people to live on Mars. How? How are you going to sustain five million people on a planet that is utterly inimical to human life? At what expense, even if it could be done (and we haven’t a clue how to do it)? What is going to be the return on this massive investment? What will these humans on Mars produce, to recover the cost of the initial investment and turn a profit? Nothing, is what. The whole thing is a pipe dream.

Going beyond that is insanity. Hawking spoke of finding other earth-like planets for humans to live on to assure human survival in case of a catastrophe on earth. Huh? If there are other earth-like planets out there, then they are inhabited. The reason that the earth is the way that it is, is because of its life.

Like Spanish conquistadors, are we going to enslave/exterminate other sentients for our own benefit? Who gave us the right to do this, even assuming, without evidence, that is possible to reach these other earth-like worlds? Who even knows if there are other worlds fit for human habitations out there?

This techno-hubris is like secular Goddism, that idea that we are going to be led to a new Promised Land, not by a supernatural God but by a technology we almost certainly can never hope to muster. Real life is no more a Star Trek movie than it is the Bible.

There is no Planet B. What we should be paying attention to is our own planet, the only planet we have and most likely will ever have. We are destroying it. We should forget about this fantasy about colonizing other worlds and focus on saving our own world for ourselves and the generations to come.

 

[Jarhyn]

It’s really weird, this idea we are going to colonize the solar system and then the galaxy and perhaps the rest of the universe.

It’s unwarranted techno-hubris, and plenty fall for it, not only charlatans like Musk but truly bright people like Stephen Hawking.

Musk want to send five million people to live on Mars. How? How are you going to sustain five million people on a planet that is utterly inimical to human life? At what expense, even if it could be done (and we haven’t a clue how to do it)? What is going to be the return on this massive investment? What will these humans on Mars produce, to recover the cost of the initial investment and turn a profit? Nothing, is what. The whole thing is a pipe dream.

Going beyond that is insanity. Hawking spoke of finding other earth-like planets for humans to live on to assure human survival in case of a catastrophe on earth. Huh? If there are other earth-like planets out there, then they are inhabited. The reason that the earth is the way that it is, is because of its life.

Like Spanish conquistadors, are we going to enslave/exterminate other sentients for our own benefit? Who gave us the right to do this, even assuming, without evidence, that is possible to reach these other earth-like worlds? Who even knows if there are other worlds fit for human habitations out there?

This techno-hubris is like secular Goddism, that idea that we are going to be led to a new Promised Land, not by a supernatural God but by a technology we almost certainly can never hope to muster. Real life is no more a Star Trek movie than it is the Bible.

There is no Planet B. What we should be paying attention to is our own planet, the only planet we have and most likely will ever have. We are destroying it. We should forget about this fantasy about colonizing other worlds and focus on saving our own world for ourselves and the generations to come.

Indeed we should be paying attention to what we have and not breaking it horribly.

We're not going to do that as a species, but we should.

 

[Bomb#20]

@Bomb#20

Kardashev scale - Wikipedia

en.wikipedia.org

Type III
A civilization in possession of energy at the scale of its own galaxy,

That would involve expanding across much of the galaxy. As far as why they'd want to do this goes maybe they want to brag about it or having that much energy is useful as far as their goals go....

The most straightforward extension of the scale to even more hypothetical Type IV beings who can control or use the entire universe or Type V who control collections of universes

So civilizations could even be unsatisfied with just filling a galaxy....

Sure, all this is possible; my point is that it isn't rational. When you're living in a Type II civilization's Dyson sphere, life is good. How would you benefit from your society trying to become Type III? That isn't to say it's a sure thing that nobody will do it; but aliens smart enough to reach Type II are pretty darn smart, so it's entirely plausible that every such species is quite smart enough to know when to say enough is enough. Think of it as the Cosmic Peter Principle -- the secret to happiness is to avoid the disastrous final promotion to a position for which you're incompetent.

Anyway, to me this seems like a credible solution to the Fermi Paradox; and it's one that doesn't imply there's any Great Filter ahead of us about to stop us from ever making it out of our own solar system. There could perfectly well already be a hundred multi-star alien civilizations in our galaxy, each thousands of light years from its nearest neighbor, and it's only a matter of time and engineering progress until we're the hundred and first.

 

[Bomb#20]

Those probes could tell you which, if any, of the solar systems in our galaxy have life..... they could use networks of probes to send the messages back. I at least would be interested in exactly how many of the solar systems have life.

No, they couldn’t.

Perhaps they could tell our great great great great grandchildren these things; I am not confident that they will care as much as you or I though.

You know what kids are like; They’ll be too busy with their heads stuck in their iPhone 32,487,692,631s, or complaining that they’re stuck with this clapped out old 32,487,692,629, and that if their parents don’t care that they’re embarrassed by their crappy old phones, why should they worry about some ancient ancestors and their stupid ancient space probes.

Yes, yes; but come on, man! Wouldn't it be viscerally satisfying to you to be able to die knowing you've set things up so that in a couple of hundred years, your probes will come back and tell all those obnoxious kids to get off your lawn?

But the larger point here is that we're talking about self-reproducing probes in connection with the Fermi paradox. So the fact that getting the answer back takes longer than a human lifetime isn't really pertinent. Who can guess whether it takes longer than an alien lifetime? You don't care to work so that your great^N grandchildren will learn something important, but to an alien with a ten thousand year lifespan, having to wait for the return on investment may be no more important than it is to a NASA engineer who devotes his career to a Pluto mission.

 

[steve_bank]

Spectroscopy tells us the composition of a star and the likely elements present in e solar system. Point being any distant ET is likely to face the same issues we do, most importantly propulsion.

Look at what it takes to get a few humans into LEO, and sustain the ISS. A large scale lunar or Martian colony is a fantasy.


Economies of scale apply to commodities like computers with a high volume.

The economics of a leet of galaxy roaming star ships is astronomical. The engibeering, design, and teting alone woud be costly.

Unless there is cheap high energy density power sources any ET will be as limited as we are.

And that assues an T with our combination of brains, dexterity, speech, writing, and barin power.

 

[bilby]

How are you going to sustain five million people on a planet that is utterly inimical to human life?

Quite.

We can’t even establish useful or long-lived colonies in the harsher parts of the Earth. The central Sahara, Antarctica, Siberia, central Australia - all are in the too hard basket for anything other than tiny settlements that remain entirely dependent upon the kinder parts of the world for their survival.

The exceptions being small bands of indigenous, usually nomadic, people, who have managed to eke out a living from the tiny local biological resources available - resources that are unique to Earth, and due to our shared evolutionary history, are perfectly suited to use by humans.

If we can’t establish a five million strong colony in Antarctica (and we really can’t), then we sure as shit ain’t doing it on Mars.

People lose sight of the fact that Science Fiction isn’t stories about our future. It’s stories about our present, and our past, set in the future.

You can get away with a lot of commentary on contemporary politics, or on the ugly side of our recent colonial past, by setting the story on Mars in 2095, so that when the people you are defaming or their descendants say “Hey, that’s mean and unfair”, you can say “I clearly wasn’t talking about you, but if the cap fits…”.

When people tell Wild West Frontier stories about colonising Mars, they’re generally telling stories about Wild West Frontier history. They aren’t actually recommending that we colonise Mars, even if they don’t consciously realise that themselves.

 

[Bomb#20]

There is no Planet B. What we should be paying attention to is our own planet, the only planet we have and most likely will ever have. We are destroying it. We should forget about this fantasy about colonizing other worlds and focus on saving our own world for ourselves and the generations to come.

For ourselves and how many generations to come?

The earth is doomed. The sun is getting hotter, same as any other main sequence star. Sunlight dissociates water vapor, the oxygen falls to the ground, the hydrogen reaches escape velocity. In a billion years or so the oceans will have boiled away and the earth will be uninhabitable whether we pay attention to it and save it from our own destructive tendencies or not. So if it's important to you whether the generations to come and the rest of our charismatic megafauna co-tenants have a life-sustaining environment, they're going to need that Planet B and the starships to take them there.

 

[Loren Pechtel]

And trillions of years before hitting that wall, we'd hit another wall: the one where our demands grow faster than our supply of space and stars, and we start to experience scarcity on the scale as if we'd stayed on earth in the very finite bubble of space accessible by then. There's this pesky little thing called c, and the funny fact that exponential growth is, well, exponential, while cubic growth isn't.

If we move into space at a constant speed in all directions at once, we'll be adding 700% to our available space in year 2. In year 11, we'll only be adding 33%, and in year 302, it'll be less than 1%. Whatever growth rate of space and resource use you deem necessary, we'll soon drop below it.

If you are travelling at the speed of light it would take at least 50,000 years to reach the limits of our galaxy - I'm not sure what you mean by year 302. Then there are a huge number of galaxies and I think some would take billions of years to reach. Are you saying that since it would eventually run out we shouldn't even bother?

He's talking about the volume of a sphere that is expanding at a fixed linear rate. (He omitted units because they don't matter.) He's saying that while growth is possible expanding to other systems that expansion does not permit growth to continue anything like forever. 302 is only relevant in showing how much the growth slows as time goes on--that's the point where the volume of the sphere only goes up by 1%. For any given rate of increase you can find a number of years where it will have slowed to that point. In the long run population growth will have to drop to effectively 0%. (And note the social problems that develop if you have a basically immortal race.)

 

[Loren Pechtel]

Sure, all this is possible; my point is that it isn't rational. When you're living in a Type II civilization's Dyson sphere, life is good. How would you benefit from your society trying to become Type III? That isn't to say it's a sure thing that nobody will do it; but aliens smart enough to reach Type II are pretty darn smart, so it's entirely plausible that every such species is quite smart enough to know when to say enough is enough. Think of it as the Cosmic Peter Principle -- the secret to happiness is to avoid the disastrous final promotion to a position for which you're incompetent.

Anyway, to me this seems like a credible solution to the Fermi Paradox; and it's one that doesn't imply there's any Great Filter ahead of us about to stop us from ever making it out of our own solar system. There could perfectly well already be a hundred multi-star alien civilizations in our galaxy, each thousands of light years from its nearest neighbor, and it's only a matter of time and engineering progress until we're the hundred and first.

But everyone believes this? Nobody wants to explore the frontiers? That's never happened in history, why should we expect it to happen now?