Is the universe old or young?

Yeah, but most last much, much longer. Our sun is actually quite large, with a much shorter lifespan. Most stars being formed today will last into the trillions of years.

(adding to babale’s post)

Plus, if we’re just discussing this in the broader, Fermi paradox sense, the lack of colonies is just the start of the problem.
There are plenty of technologies that could spread around the Galaxy much faster than the glacial pace of an expanding civilization.

Heck, humans are already capable of littering the Galaxy with junk, we’ve just played nice so far and just dropped a couple voyagers.

Yeah, I’ve never gotten the whole “travel outside it’s own solar system is impossible from a practical standpoint” assertion.

We watch rocks pass through our solar system that came from others from time to time, probably more often as our telescopes get better. If a dumb rock can do it, why can’t an intelligent species?

And even if we decide to stay home, and there are reasons why we may not want to go, or to let others go, that doesn’t mean that we will be happy with the resources around here. It’s not really all that hard to put together some probes that will go out to other solar systems, gobble them up, and send their resources back to us. And send them out we should, especially as and if we get the technology to send them out to other galaxies, and up to relativistic speeds, so that we can try to catch some of that stuff before it disappears forever.

Slightly anthropomorphized to skip a few steps in logic that would take up pages or even papers to go through, the universe wants to increase in entropy, life wants to increase the entropy of the environment it is in, so the pressure is on life to go out into the universe and start increasing its entropy. (Of course, this means that the universe is young, but the cancer that is life just metastasized.)

I was watching Frasier Cain last night, and he mentioned that he saw a stat that said that for every second that we wait, we lose 10^14 lifetimes worth of resources over the cosmic event horizon. Double hearsay on the stat, so double dose of salt on it, but that’s in the right ballpark.

If we stay here on Earth, no matter how clean we are, we are all dead in around 500 million years when the sun gets too hot to sustain life. If we stay in the solar system, that only buys us another few billion. Only if we get out into the universe proper do timeframes of trillions of years or greater actually have any meaning.

Right, in the Fermi Paradox context it doesn’t matter if the aliens we run into are biological and evolved from microbes into a technological species, or if they are self replicating robots who rose up against and destroyed the aliens who originally created them.

Or they are self replicating robots sent here to dismantle our solar system and turn it all into Ikea furniture for some aliens in the Messier 87 galaxy.

Interesting. Checking this, the estimate is 6 stars for every Brown Dwarf, which is not really a star.

Although brown dwarfs never truly become stars, some of them are able to act the part, for a short while. To start fusion, the very lowest-mass stars need about 80 times the mass of Jupiter. However, if a brown dwarf has at least 13 times the mass of Jupiter, it can ignite a limited form of fusion. These brown dwarfs fuse a heavy isotope of hydrogen, called deuterium, into helium, releasing energy like a star. Nuclear fusion ends once the supply of deuterium is used up, and that supply is very limited. Once fusion ends, the brown dwarf goes back to contracting, cooling, and glowing.

It doesn’t appear from what I read that a brown dwarf is stable enough to support planetary life in the long term.

Brown dwarfs are an odd set of objects that are neither planets nor stars. Rather than forming like planetary seeds in the disks around protostars, brown dwarfs begin on their own like stellar seeds. However, they never pull in enough material to start nuclear fusion; instead, they slowly contract, cool, and glow in the infrared from the release of gravitational energy, like Jupiter. Eventually, they simply fade away. Some people think of brown dwarfs as failed stars.

Not to mention, all those twinkling stars are wasting precious energy. Trillions upon trillions of tons of hydrogen that could be stored until the end of the universe and then used to power fusion reactors for unimaginable numbers of years, keeping us alive far longer than we could survive otherwise. All wasted on a light show that most of us can’t even see properly, due to pollution (both light and atmospheric).

Where’s our collective dad, yelling at us to turn out the lights we aren’t using?

Everything is just going to fade away.

Here’s a great visualization of the emptiness of the universe, just keep scrolling right:

https://joshworth.com/dev/pixelspace/pixelspace_solarsystem.html

I agree that it’s unlikely to be the case, given enough time and technological advancement. There’s no reason a species couldn’t potentially develop technology to travel at a significant fraction of light speed. Time dilation would then also allow them to make the trip in a relatively short amount of proper time, even if it might take hundreds of thousands of years in the reference frame of the destination star system.

The answer to the Fermi Paradox is not clear, but it may be that we are quite wrong in ascribing such human motivations to advanced alien civilizations. Maybe they have much better things to do than “colonizing” other star systems. Furthermore, for two such civilizations to meet, they have to meet at just the right four-dimensional coordinates in space and time, which may be a really tall order. Maybe civilizations in general are much more short-lived than we think, being limited in longevity by the discovery of such extinction-inducing things as nuclear energy.

To be clear, I did say that it was an oddball conclusion and I posted it to support the statement that we really don’t know how long the universe will exist, and haven’t even defined what that means.

However, the consensus of opinion, based on the longevity of smaller stars, the number of stars still being formed in “star nurseries”, the size of the universe, its expansion, and the progression of entropy, a life expectancy for the universe “as we know it” would seem to be on the order of trillions of years, probably many trillions. While the number of new stars being born in the Milky Way is indeed just a few per year on avearge, and much less in the Andromeda galaxy with which we will merge in about 4.5 billion years. Still, it’s been estimated that in the observable universe as a whole, probably somewhere around 150 billion new stars are born every year.

Yeah, that’s the thing. To me, the LIFE of the universe is the universe in a state viable for supporting life, not some dark, dead remnant awaiting proton decay.

Yeah, but red dwarfs is probably where it’s all at, not brown dwarfs.

I’ve often said that some people look into the sky and see wonder and splendor of countless twinkling lights, I look up and I see a sky full of burning oil wells.

Doesn’t need to be to all of them, just one. So the question becomes, will humans stop having such motivations in the future, and if so, why, or are humans somehow unique in having them?

Unless a civ takes up the entire reachable universe and lasts till the end of it. Which means that in order for them to meet, all it needs is another in the same patch of universe.

Are you saying that you think that we are on a path towards extinction due to nuclear energy?

That still gets us trillions of years easily. And, as @Chronos alluded to earlier, if we were aliens living the equivalent of trillions of lifetimes in the femtoseconds before the electroweak symmetry was broken, then we would be looking at the future of the universe as a bleak, dreary, and lifeless place, not knowing what is actually to come next.

Not sure I agree with you, there. We’ve made absolutely fascinating, mind-boggling discoveries about the nature of the universe without yet finding any life outside of earth. I think it’s a valid philosophical and cosmological question to ask how long this amazing thing, with its intricate physical laws and fascinating processes at both quantum and macro-cosmic scales, will continue to be around even if there is no one there to observe it.

I’m saying the hypothesis has been raised, not with respect to the peaceful uses of nuclear energy in general but with respect to its weaponization. Given past history – not just a very large number of things that could happen, but things that actually have happened in the age of nuclear weapons, the chances of nuclear obliteration in any given year are distinctly non-zero. The hypothetical question is, how many years until the statistical probability of nuclear holocaust swings to “more likely than not”?

I guess that’s actually two questions. One is the probability of a full nuclear exchange, and the other is the probability that that wipes out humanity.

There are reasons to hope that the former actually decreases with time, kind of a converging series, where the accumulated chance never actually reaches one. Up until this last year or so, I would have thought that we were on that track, though recent events have made me a bit concerned.

As to the latter, I don’t think that, if we launched off every nuke humanity owns, it would actually kill us all. Billions would die, and life would suck for the survivors, but I really think that there would be survivors. The question then becomes, when those survivors rebuild civilization, do they take the lessons learned and steer away from such destructive ends, or do they just repeat the same mistakes and end up in the same place, over and over again?

Anyway, point being, there’s little use in bringing up things that could happen to us or to aliens to prevent them from expanding into the universe, unless you can demonstrate that it is something that every, or extremely close to every civ would encounter. If only .01% of civs don’t run into that filter, then we should expect to see some of them.

And all that ends as soon as we have any sort of self sustaining colonies off of Earth. Realistically, the only useful thing about Mars is that it could be a place to hide from a homicidal Earth.

It doesn’t necessarily ascribe such motivations though.
The point is not merely why don’t we see any of the kinds of tech and exploration that advanced humans would probably do. It’s why don’t we see any of those kinds of technology or anything else detectable ?
As popular as psychological / sociological answers to Fermi are, they don’t stand up well to scrutiny, as we need to posit that every individual of every civilization of every species always chooses not to leave evidence that would be detectable across space.

Who knows if humans are going to make it, but in terms of Fermi filters, we can already say that this one doesn’t look convincing.
Humans are an eyeblink away from being able to spread across the galaxy. And we are among the most violent of primates. It’s possible that a certain degree of violent and competitive behaviour is necessary for sentience to evolve. But looking around at our primate cousins, including the extinct species, it doesn’t look as though human-level aggression is strictly necessary.
So, if we can make it to the stars, it implies nuclear annihilation is not that hard a bullet to dodge.

Once again, I have to go back to Fraser Cain and quote/paraphrase him. He points out that if there is a great filter ahead of us, one that took out everyone else before they got much further than we have, it must be something that is both unavoidable and unanticipatable. If we are able to anticipate it, then we are able to avoid it. Maybe we won’t, but somebody will. So, in a way, it’s useless to try to figure out what’s gonna take us out, as more or less by definition, we won’t know about it until it’s too late.

My optimism is that the great filter is behind us, but my pessimism is that the galaxy is full of dead civilizations that got to about as far as we have, and no further before dying off.

Yep, agreed. I was just disagreeing about nuclear annihilation. Which, while for sure an existential threat to Homo sapiens (as we have both the smarts to make nukes and the stupid to use them), doesn’t work well as the primary filter for Fermi.

But yeah, maybe the real great filter is on its way to us at light speed…

That’s what makes the Fermi paradox so fascinating (and why it’s so unfortunate that the majority of people misunderstand the concept, and think it is just saying that no-one can think of even a single plausible reason why we don’t see ETs).

It would suck for us, it would certainly suck for me. I’m not in any shape to try rebuilding civilization in a post apocalyptic world.

But it wouldn’t be the end of humanity.

Or is currently ticking away in some mad scientist’s basement.

On that note, cold worries me more than hot. When they were turning on CERN, people were worried that it would create black holes, or rip the fabric of space or something. It was pointed out that the energies at CERN are dwarfed by natural events in the universe all the time. Cosmic rays have far more power than the beam in the collider.

OTOH, I was watching something, and they said, “Inside that chamber is the coldest spot in the universe.” and that worried me a bit, as those are not conditions that are common in the universe, and that’s the sort of thing that I would think could initiate vacuum decay.

What would cause me the greatest existential fear for the future of our species would be that we detect intelligent, tool using life nearby in the galaxy. That means that getting to tool use is not the great filter, and it is instead in front of us.

True, I’ll grant that there could, in principle, be “life”, or whatever we’re calling it, based on gravitational waves or the like. I’ve often contemplated the idea myself. But the problem is, time would not be on such a being’s side: Such beings would operate far, far slower than we do. Which wouldn’t be a problem, given the unfathomable æons (by our standards) that will pass after the stars are gone… except that they’ll still be slaves to the same dark energy timescale as us. Assuming that the cosmological constant is, in fact, a constant, every ten billion-ish years, the Universe will double in size, and will continue to do so really truly forever. That’s not a problem for short-lived quick-thinkers like us, but it puts a hard limit on just how slow a “brain” can work, lest it be torn asunder before it has a chance to form a thought.

Now, it may be that the Cosmological “Constant” isn’t, on sufficiently long timescales. It may be that a lot of things we think we know are in error. But to the best of our knowledge, there just isn’t room for another tier of life below us.

Though I will concede that, however many ages there are, and however relevant that is, our own age, the stellar age, is very young, since there will be stars for hundreds or thousands of times as long as there have been so far.

No, that’s what prompted Fermi’s observation. It’d be easy to colonize the Galaxy; it’d only take a few million years. Which may seem like a long time to you, but compared to stellar lifespans of tens of billions of years, it’s nothing.

Personally, I kind of suspect that the Great Filter was the Great Oxygenation Event: Sure, it ruined the ecosystem for most of the life that existed at the time, but it also left those that survived with a vast supply of available chemical energy. It may be that on most life-bearing worlds, the creatures that evolve have enough sense to hold on to their own energetic chemicals for their own use, and so none gets to take advantage of the bounty of all. Which, I suppose, would be good for us, since we’re well past that filter, but it would also mean that we’ll never meet any other civilizations, which would be a real bummer.

Maybe, but it also means no competition for resources.

If Columbus had arrived in the Americas, and found no hominid life here, the continent being truly empty of human life, our exploration and exploitation of the continent would have been on somewhat more ethical terms.

If we go out, and we find intelligent life out there, then we have to question what rights we have to take what it may want to use. If there isn’t any other life out there, then it’s ours for the taking.

And maybe it’s already here, going around the planet at light speed.