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The Fermi paradox revisited: Technosignatures and the contact era

arxiv.org

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

#11

Post by cannonpr »

maerF0x0 wrote: post #9
MontyCarloHall wrote: post #4

Earlier quoted context omitted.

I post this on every Fermi paradox thread. Non-directional radio transmissions (e.g. TV, broadcast radio) would not be distinguishable from cosmic background radiation at more than a light year or two away [0]. Highly directional radio emissions (e.g. Arecibo message) an order of magnitude more powerful than the strongest transmitters on Earth would only be visible at approximately 100 light years away [1], and would…

> Non-directional radio transmissions (e.g. TV, radio) would not be distinguishable from cosmic background radiation at more than a light year or two away this is going to come across as sarcastic in text, I genuinely mean this. Why don't the authors know this? Why doesn't someone tell them?

Because I suspect that under focused analysis the signal won’t quite look like cosmic radiation background. Now I also haven’t done the analysis, but information, and entropy are funny things. Will they get to watch a human TV show ? Hell no. Would it look “random” versus showing that it once contained some structured information ? I think that’s a very open question. There are probably more serious papers that deal with the matter and how long and far “techno-signatures” survive in the noise.

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

#12

Post by api »

antirez wrote: post #5

The first alien we will ever encounter is likely a neural network we built with our hands.

If something visits us from another star system it's also likely to be an AI.

Hibernation for thousands of years to travel between stars would be almost trivial for machine intelligence. Just turn yourself off. It'd be easy to tie this directly to solar power. Have an array of solar panels that powers you near a star and in interstellar space you just naturally go to sleep. When you approach the next star system the light generates power and wakes you up.

Star travel is easy if you don't have a fixed life span or are able to just deactivate. No need for crazy physicists' nightmare propulsion systems to travel close to the speed of light or wormholes or any of that far-out stuff. Chemical propulsion will do just fine.

For humans or any other biological entities to travel between stars they'd need to be able to basically die and be resurrected like tardigrades. We can imagine an alien biology that would make this easier, but for humans we have no idea how to do this and survive.

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

#13

Post by douglaswlance »

If we assume alien life in the universe is predatory and seeks to consume other life forms, and since the universe allows detection from other species over infinite distances and time scales, we would expect life in the universe to either be totally undetectable or else be consumed by life that is totally undetectable.

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

#14

Post by pharke »

Mistletoe wrote: post #7
MontyCarloHall wrote: post #4

Earlier quoted context omitted.

I post this on every Fermi paradox thread. Non-directional radio transmissions (e.g. TV, broadcast radio) would not be distinguishable from cosmic background radiation at more than a light year or two away [0]. Highly directional radio emissions (e.g. Arecibo message) an order of magnitude more powerful than the strongest transmitters on Earth would only be visible at approximately 100 light years away [1], and would…

I feel the same way. How do the SETI people explain this away and justify their search? One light year is tiny, I think it would take an incredibly generous Drake equation estimate to make that contain intelligent life. Same for 100 light years too. But I lean towards pessimistic Drake equation values. Life is even more rare and precious the more I dig into the equation. > The true stellar density near the Sun is est…

I would have to assume that they know this and are in fact only looking for messages that are purposefully sent at very high power. It's also why they favor listening at the hydrogen line since transmissions at that frequency stand the best chance of penetrating through cosmic dust, i.e. you would only use that frequency if you were intentionally trying to transmit across interstellar distances.

I think they don't popularize the downsides of a radio search since it could threaten their already tenuous funding. Basically, they have to be optimistic in order to maintain the pittance of a budget given to them which allows us an extremely small chance at detecting a purposefully sent signal if we happen to be in the right place at the right time and listening on the right frequency pointed in the right direction, etc.

In order to do SETI right we really need radio telescopes in solar orbit far away from the Earth and enough of them so that they can cover all of the nearby stars or other likely directions for signals to originate from. The only way we're going to get there is if space launches continue to become a lot cheaper. Fingers crossed.

https://en.wikipedia.org/wiki/Hydrogen_line

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

#15

Post by bnralt »

krapp wrote: post #3

Another Fermi Paradox thread. Take a shot any time von Neumann probes are mentioned. Regarding the paper (or at least its abstract) it's worth mentioning that our own radio transmissions have become significantly less likely to be detected after our transition to digital, and that electromagnetic signals dissipate, so they might no longer be recognizable as intelligent signals beyond a certain distance. That would se…

I've been wondering what the advantage of von Neumann probes are. Once you have the ability to autonomously construct probes, it seems like it would be easier and faster to mass produce them in one solar system and send them directly to their destinations.

For instance, with a von Neumann probe you have to have probes with additional mass for self-replication, have it accelerate halfway to point A, decelerate halfway their, spend time replicating a new probe that will accelerate halfway to point B and then decelerate, then spend time manufacturing a new probe, then have that accelerate halfway from point B to point A, then decelerate the second half of the way, etc.

But if you can automate manufacturing, you can just make specialized devices that mass produce probes in one system, and send them directly to their destination, without waiting for the parent probes to stop at all the in between points to do some manufacturing. And the probes are going to be much lighter because they don't need replication devices in them.

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

#16

Post by DiggyJohnson »

douglaswlance wrote: post #13

If we assume alien life in the universe is predatory and seeks to consume other life forms, and since the universe allows detection from other species over infinite distances and time scales, we would expect life in the universe to either be totally undetectable or else be consumed by life that is totally undetectable.

That could very well be true but it's a bold assumption indeed.

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

#17

Post by pharke »

douglaswlance wrote: post #13

If we assume alien life in the universe is predatory and seeks to consume other life forms, and since the universe allows detection from other species over infinite distances and time scales, we would expect life in the universe to either be totally undetectable or else be consumed by life that is totally undetectable.

That's not a great starting assumption. How would the economics of travelling hundreds or thousands of light years in order to "consume" (whatever that means) other life forms work out? What is the benefit? How would it be worth the investment?

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

#18

Post by staunch »

My pet theory (which I'm sure is not original) is that absolutely all intelligent life, through AGI and/or genetic engineering, eventually converges into an undifferentiated super intelligent state.

These super intelligences continuously decide, for one reason or another (but always the same reason(s)), not to expand their presence into the universe in an invasive way.

Maybe it would simply be unnecessary for them to do so, or maybe they consider it unethical, or maybe they do it but in a way that is undetectable to non-super intelligences.

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

#20

Post by fnordpiglet »

krapp wrote: post #3

Another Fermi Paradox thread. Take a shot any time von Neumann probes are mentioned. Regarding the paper (or at least its abstract) it's worth mentioning that our own radio transmissions have become significantly less likely to be detected after our transition to digital, and that electromagnetic signals dissipate, so they might no longer be recognizable as intelligent signals beyond a certain distance. That would se…

Further because a sufficiently powerful compression+encryption scheme would be indistinguishable from noise, how would we even know any pattern is or isn’t a natural noise or an artificial noise?
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