Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

The Fermi paradox revisited: Technosignatures and the contact era

arxiv.org

Post reply on HN
Print view View original

171–180 of 353 posts

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

#171

Post by Ancalagon »

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…

Abiogenesis happened Way too early in earths development for there not to be life elsewhere imho

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

#172

Post by Ancalagon »

georgeg23 wrote: post #108
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 don't think people realize how quickly EM radiation falls off with distance, and how large the scale of "transmitters" would need be before we could detect. Today we can finally, barely detect massive planets occluding suns, and we can only do this in our neighborhood of this galaxy. Modulated communication from a source not at planetary scale is currently impossible for us to detect. We need something much much bi…

On the other hand all those tech developments you pointed out we’ve only discovered and utilized in the last 100 years. Now imagine a civilization with 10 times that experience/time

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

#173

Post by random314 »

whatshisface wrote: post #168
random314 wrote: post #167

Earlier quoted context omitted.

The central limit to theorem states no such thing even if the steps vary independently. Central limit theorem states that the "average" of "any" kind of distribution is normally distributed. It doesn't make the underlying distribution behave in any particular way.

SD divided by mean also tends to fall.

SD is defined by dividing by the square root of the number of samples. It is never divided by the mean - as this metric has no relevance.

The SD as it relates to the central limit theorem is the confidence in the estimation of the average E(X) of a distribution. It means that the SD reduces i.e. confidence increases as the number of samples increase. You don't need the central limit theorem for this. It follows from the definition of standard deviation where it has the square root of the number of samples in the denominator.

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

#174

Post by simonh »

m4rtink wrote: post #166
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 might be able to see their drive plumes if they use some of the theoretical high performance reactive drives we know of on big crafy. Eq. various fusion plasma drives, Orion, Nuclear Salt Water Rocket release so ludicrous ammounts of energy that they might be visible over interstellar distances, especially if pointed in our general direction when running. Massive solar sails as well would be very very big and very…

> release so ludicrous ammounts of energy that they might be visible over interstellar distances

Ludicrous at human scales, but utterly insignificant compared to the output of even the smallest stars. Bear in mind that small stars are hard to detect more than a few dozens of light years away. Well you can detect them, but they are hard to range. It’s difficult to pick out nearby stars in the dense stellar background as being nearby. Take a look at the deep field images to get an idea of the clutter. A drive plume would just be utterly lost in all that background noise.

People imagine the sky as being inky black with a few bright objects to look for, and that even a drive plume light years away would stand out against the blackness, but that’s not how it is at all. The sky is full of distant clutter that makes picking out particular objects extremely difficult. And if your plume is in a system anywhere near a star, forget it. You’d have to know exactly what you’re looking for and make extremely precise long term observations to have any chance whatsoever.

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

#175

Post by geertj »

troyvit wrote: post #129
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?

It would prove life is abundant, but it would still not prove that intelligent life is.

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

#176

Post by AlbertCory »

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…

Well said. The "Drake Equation" is complete and utter garbage. There is no such thing as a "probability" of any of those terms, in the way we normally understand probability, i.e. dice or card games.

That said, there probably are intelligent civilizations somewhere in the universe, but we have that pesky problem of distance and the speed of light, as you said. People like to imagine that eventually civilizations find a way around it, but in all likelihood they don't.

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

#177

Post by credit_guy »

m4rtink wrote: post #166
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 might be able to see their drive plumes if they use some of the theoretical high performance reactive drives we know of on big crafy. Eq. various fusion plasma drives, Orion, Nuclear Salt Water Rocket release so ludicrous ammounts of energy that they might be visible over interstellar distances, especially if pointed in our general direction when running. Massive solar sails as well would be very very big and very…

Space is large. If you don't look in some direction, you don't see what's there. Big, or not.

Let's take the Orion engine. It keeps blasting away thermonuclear bombs. Are we looking straight at it? Why? Ah, maybe because they are in the neighborhood of a star. But then we are also looking at the star, which is trillions or quadrillions times brighter. Same for fusion plasma drives or anything else.

If the Orion engine is traveling between stars, we'd have a chance, but then how would we know where to look ?

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

#178

Post by mcculley »

_tom_ wrote: post #82

My other pet theory is that organic life forms are an intermediate step in the development of intelligence. No one will bother with us, until the inevitable artificial intelligences develop.

There won’t be anything artificial about such intelligences. I have taken to calling them synthetic intelligences.

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

#179

Post by Ancalagon »

1970-01-01 wrote: post #25

Until SETI locates something like a pulsar braking and accelerating to signal prime numbers we're really really really unlikely to stumble onto more life. Space is just too big.

The ultimate flex from a type 3 civ, love it!

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

#180

Post by andruby »

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…

That's a great list of filters. Thank you.

Do you happen to know books, movies, articles or other media that expand on this?

Post reply on HN