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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

#121

Post by namirez »

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…

Then you need to explain how life on Earth started a short period after it cooled down. Yes, it took a long time for complex life forms to emerge but life itself started right off the bat.

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

#122

Post by btilly »

cortic wrote: post #68
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.

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 lots with rocky planets, and lots with gas giants. Ours is the only system with BOTH rocky planets AND gas giants.

Filter 3. Supernovas are dangerous. For example we are currently in the Local Bubble. Which is the result of a supernova about 4 million years ago which would have wiped us out if we were this close when it happened. Luckily for us we have a weird orbit where we only pass through the galactic plane every 30 million years or so, and spend most of our time well away from potential supernovas.

Filter 4. Planets need to be in the habitable zone, around a star where that zone remains habitable for a very long period. Most solar systems have no suitable planet.

Putting these together on a back of the envelope, it is likely that we're the only solar system in our galaxy which is likely to remain habitable and stable for long enough that complex intelligent life could evolve.

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

#123

Post by dvh »

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…

If you look at the wikipedia's list of 100 nearest stars, only 4 are single main sequence stars: Tau ceti, Sigma Draconis, 82 G. Eridani, Delta Pavonis. All other are either binary stars with unpredictable orbits or flare stars. Stars where civilizations can quietly mature are rare.

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

#125

Post by throw827474737 »

d_silin wrote: post #39
lapcat wrote: post #35

Earlier quoted context omitted.

We're in the process of wrecking our own ecosystem. We have the military capability to wipe ourselves out at any moment. The use of nuclear weapons has been discussed a lot lately, even nuclear first strike. And when some natural threat arises — take the pandemic for example — we turn on each other and bicker. "Don't Look Up" seems quite plausible.

Above statements are proving my point. Despite its many flaws human civilization is stronger than ever and is on the verge of expanding beyond the home planet.

Proving what? With a sample size of 1 that is all just survivor bias so far... and after all we know it is ending soon

We need a real godly or technological wonder (a real wonder, not something like fusion what is on the horizon), or maybe just humanity coming to reason and agreeing and uniting and doing the right thing (ok yes, now I am getting really ridiculous, the least likely to happen) to avoid that filter.

With a bit of luck humanity may endure though.. in the hundred thousands on medieval level with some more luck..

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

#126

Post by buryat »

lugu wrote: post #124

My pet theory to address the Fermi Paradox is that we live in a unpleasant place in the universe/multiverse. Out there, exists a place much more attractive (think of another dimension with much better physical properties). And this is where everybody is.

the grass is always greener

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

#127

Post by martinclayton »

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…

For a long time we weren't at all sure whether the expansion of the universe would stop, leading to a "big crunch", or continue forever, slowing down for eternity. Then we found the other option appeared to be supported by observational evidence: the expansion is accelarating.

We're in a similar position with finding life elsewhere. The vague error bars in many terms in the Drake (so-called) equation shouldn't be read as indicators of (im-)probability, more as signs of major gaps in our understanding. We slowly inch towards better data. Surprise is likely on the journey. I would say though that, so far, we're pretty sure there is some life in the universe, but nothing else.

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

#128

Post by jasonwatkinspdx »

AlanSE wrote: post #50
causality0 wrote: post #36

The universe we find ourselves in isn't very compatible with a species like our surviving for an extended period. If humans exist for millions of years we're going to either spread out to fill the galaxy or our machines will. The fact earth was free to develop us means that no other species like us existed long enough to beat us to it. We ought to hope that's because species find some other priority besides expansion…

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…

There's no exogenous law that exponential trends continue indefinitely. In fact I'd argue it's much more common to see sigmoid behavior where eventually negative feedback loops cause a plateau.

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

#129

Post by troyvit »

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…

How would your perception change if life was discovered on the moons around Saturn and Jupiter? Does that increase the likelihood of life outside our system?

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

#130

Post by denton-scratch »

topaz0 wrote: post #109
denton-scratch wrote: post #101

Earlier quoted context omitted.

Luckily, the aliens are wearing Swiss wristwatches, they know how long a minute is, and so are able to notice that the intervals are a prime number of minutes :-)

If the intervals are relatively prime, it wouldn't take much to work out what the intended time unit was.

OK, that makes a bit of sense. But I don't know what it means for two real quantities to be relatively prime. Primality is about factoring, right? And you can only factor integers. So to observe primality, you'd have to partition interval measurements into an integral number time-units.

Can two reals be relatively prime no matter how you partition them into integers?

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