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The Fermi paradox revisited: Technosignatures and the contact era

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Re: The Fermi paradox revisited: Technosignatures and the contact era

#151

Post by superposeur »

spookthesunset wrote: post #111
superposeur wrote: post #102

In my opinion, the excitement occasioned by the discovery of so many exoplanets has clouded our collective judgement on the Fermi Paradox, leading the overwhelmingly most probable resolution to be underemphasized. Namely: there is no life out there. Not due to baroque mechanisms such as techno-self-destruction but just due to its sheer unlikeliness. As large as the number of stars in the observable universe is (let’s…

I think the probability of there being other life is much closer to 100%. There just has to be. Our universe offers way to much of the correct “stuff” that can create life that it just has to exist elsewhere. Why haven’t we seen it? Well that is one of life’s great mysteries. But the idea we are all alone in this giant thing called the universe… it just doesn’t feel right. The more we learn about things the more we r…

I fear that "much close to 100%. There just has to be" (as much as I too would like to share in this sentiment) may be an anthropomorphic projection and wishful thinking. Anthropomorphic because we are living creatures and assume that there must be other living creatures in the region of the universe we can see, even if just biochemically.

But, one thing we are able to estimate is the number of stars in the observable universe -- that collection of stars in causal contact with us. It is far from infinite. In fact, not that much larger than the number of atoms in a macroscopic chunk of matter. The number of possible games of chess is incomparably vaster.

If by "universe" we mean everything out beyond our causal horizon in an infinite universe, then I would guess that yes, there is other life. Actually, there are other copies of you too, because everything that can happen does happen in an infinite universe. The hinge of my point is that the observable universe is not infinite.

This is not to say, by the way, that we should not continue looking for traces of life or to be open to these.

Re: The Fermi paradox revisited: Technosignatures and the contact era

#152

Post by btilly »

JumpCrisscross wrote: post #144
btilly wrote: post #122

Earlier quoted context omitted.

BS. Filter 1. If we had no large moon, roughly every 30 million years or so our axial tilt would become too extreme for life. We do not have another example of a planet with a moon to rival ours in relative size. Filter 2. Without Jupiter acting as a cosmic vacuum cleaner, we'd predictably be hit by enough asteroids and comets that we'd never have evolved. In thousands of solar systems that we've found, we've found l…

My big one is multicellular life. Mitochondria are sooo weird.

Multicellular happened over and over again.

Mitochondria are weird, but we don't know that such organelles are necessary for life to become intelligent. And we don't know how weird that capture was. It is easy to make an argument for improbability. And it is easy to make it too extreme, like the absurd arguments that Creationists use against evolution.

Re: The Fermi paradox revisited: Technosignatures and the contact era

#153

Post by worldsayshi »

Izkata wrote: post #106
marcosdumay wrote: post #43

Earlier quoted context omitted.

> because otherwise the reason we're free to exist is because species like us always wipe themselves out before they spread That's a complete non-sequitur. There can be plenty of reasons for a species like us never appearing on the first place, and they are way more reasonable than postulating that life like us always destroy itself.

> There can be plenty of reasons for a species like us never appearing on the first place We already have an example of it, too: Look how long the dinosaurs were around compared to humans.

Yes I wonder if there was some particular condition that prevented higher intelligence to occur before recently. Or if it's just sort of "pure chance".

Re: The Fermi paradox revisited: Technosignatures and the contact era

#154

Post by twawaaay »

credit_guy wrote: post #149

The Fermi paradox is good for a nice chat at a party. But it's not a paradox at all. Imagine there's an alien civilization in our galactic neighbor Proxima Centauri. How would we know they are there? To make it more plausible. Let's say we figure out a way to send a space probe to Proxima Centauri. How do we communicate with that probe? Easy, you say, just like we communicate with the Voyagers: they point a reasonabl…

We've been able to fly or emit radio signals only for a bit more than 100 years.

If there exist any other civilisations and we assume they start independently, there should be ones that started billions of years ago. Which is enough to visit entire galaxy even at very slow speeds.

The paradox is that we are not seeing any signs of any other intelligent life.

Re: The Fermi paradox revisited: Technosignatures and the contact era

#155

Post by dragonwriter »

whatshisface wrote: post #150

If you assume that intelligent life has to pass a certain number of "steps" to develop, doesn't the central limit theorem dictate that the more of those steps there are, the closer in time each separate species will achieve intelligence?

If you assume that they vary independently, yes.

Re: The Fermi paradox revisited: Technosignatures and the contact era

#157

Post by worldsayshi »

btilly wrote: post #122
cortic wrote: post #68

Earlier quoted context omitted.

We are actually running out of places in our history to fit a great filter. Most of the events in our evolution seem probable, even inevitable. In fact the only place IMO that's really left is the emergence of the first self replicating RNA molecule. But even that seems too probable to be a great filter. And if its not behind us, it has to be in-front of us or we are under a great misapprehension about the nature of…

BS. Filter 1. If we had no large moon, roughly every 30 million years or so our axial tilt would become too extreme for life. We do not have another example of a planet with a moon to rival ours in relative size. Filter 2. Without Jupiter acting as a cosmic vacuum cleaner, we'd predictably be hit by enough asteroids and comets that we'd never have evolved. In thousands of solar systems that we've found, we've found l…

Mentioned elsewhere in the thread:

Filter N: Even if life is complex it might not be likely to become intelligent enough to send signals and venture into space. It took quite a long time before we showed up.

Re: The Fermi paradox revisited: Technosignatures and the contact era

#158

Post by thereddaikon »

btilly wrote: post #114
thereddaikon wrote: post #92

Earlier quoted context omitted.

I think the answer is pretty obvious, we are the precursor species. Or it could be any number of things other than nobody out there. For example, advanced life could be out there but it might be rare enough that you only end up with a handful of space capable civilizations at any one time. The milky way is a big place. If we assume that ultimately there isn't a clever way around the speed of light then two civilizati…

Von Neumann pointed out that an advanced civilization, with technology that we can predict should be developable, can colonize the entire galaxy in roughly 10 million years. Which is a blink of time by geological standards.

Von Neumann was much smarter than I but for such a calculation you have to make so many assumptions as to make it worthless. How can we possibly be able to predict what happens to a civilization in 10 million years?

And yes I am aware of Von Neumann probes. But as someone else pointed out there may be secondary effects we aren't even aware of.

Re: The Fermi paradox revisited: Technosignatures and the contact era

#159

Post by credit_guy »

twawaaay wrote: post #154
credit_guy wrote: post #149

The Fermi paradox is good for a nice chat at a party. But it's not a paradox at all. Imagine there's an alien civilization in our galactic neighbor Proxima Centauri. How would we know they are there? To make it more plausible. Let's say we figure out a way to send a space probe to Proxima Centauri. How do we communicate with that probe? Easy, you say, just like we communicate with the Voyagers: they point a reasonabl…

We've been able to fly or emit radio signals only for a bit more than 100 years. If there exist any other civilisations and we assume they start independently, there should be ones that started billions of years ago. Which is enough to visit entire galaxy even at very slow speeds. The paradox is that we are not seeing any signs of any other intelligent life.

Only if they are in our own Solar system. But you can easily imagine a supercivilization visiting lots of solar systems, but not establishing permanent colonies everywhere. As I said, what if 5% of the solar systems are teaming with life? That would still be tens of millions of solar systems in our galaxy. The diversity of life could be something to make Star Wars look unimaginative. And we'd have no idea they are out there.

Re: The Fermi paradox revisited: Technosignatures and the contact era

#160

Post by rolenthedeep »

thereddaikon wrote: post #92
AlanSE wrote: post #50

Earlier quoted context omitted.

That argument seems to violate the basic rules of exponentials. If an advanced species did settle on an stasis, then that will only last until some subset of the population decides to go beyond the stasis. Particularly for a space-faring civilization, the time scales and resources are so fast, that any multiplication factor beyond unity will eventually go bananas. Any individuals with the prerogative to multiply will…

I think the answer is pretty obvious, we are the precursor species. Or it could be any number of things other than nobody out there. For example, advanced life could be out there but it might be rare enough that you only end up with a handful of space capable civilizations at any one time. The milky way is a big place. If we assume that ultimately there isn't a clever way around the speed of light then two civilizati…

Us being (one of) the first species is the most likely answer IMO. It violates the anthropic principle, but that doesn't account for everything.

By all estimates of the age and expected lifespan of the universe, we are extremely close to the beginning of all existence. We know that life takes an extremely long time to evolve, and life on Earth is young compared to the age of the system.

That we don't see a sprawling galactic civilization means one thing: there hasn't been enough time for one to emerge.

All the great filter arguments fall apart when you consider the nearly infinite nature of the universe. Given enough life supporting planets, at least one species would emerge, pass the great filters, and become large enough for us to observe.

That we don't see anything just means no one is there, yet.

Being alone in this universe would be terrifying and frankly untenable. Being first, however, is exciting.

I doubt that we are the first and only life in this universe, but it seems obvious that we are very, very early in the life of the universe, and we therefore are one of the first species to ask this question.

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