Climate Change and Fermi Paradox

[EdEarl]

Phys.org

 

So why don't we see advanced civilisations swarming across the universe? One problem may be climate change. It is not that advanced civilisations always destroy themselves by over-heating their biospheres (although that is a possibility). Instead, because stars become brighter as they age, most planets with an initially life-friendly climate will become uninhabitably hot long before intelligent life emerges.

 

...

 

Over the past half-billion years, a time period for which we have reasonable records of Earth's climate, the sun's surface temperature increased by 4% and terrestrial temperatures should have risen by roughly 10°C. But the geological record shows that, if anything, on average temperatures fell.

Perhaps technology development by intelligent life is an exceptionally rare event.

[dimreepr]

I think its distance not a lack of advanced civilisations, as a more likely reason we don’t see what, I think must be out there.

[EdEarl]

I think its distance not a lack of advanced civilisations, as a more likely reason we don’t see what, I think must be out there.

I agree that distance and the speed of light will limit manned travel. On the other hand, I think there are several, perhaps many, things that limit our ability to travel and communicate with other civilizations. And, if technological civilizations were common, we would have heard one by now.

[dimreepr]

I agree that distance and the speed of light will limit manned travel. On the other hand, I think there are several, perhaps many, things that limit our ability to travel and communicate with other civilizations. And, if technological civilizations were common, we would have heard one by now.

 

 

But why? Any signal we send out, however strong and confined must diverge and thus weaken, over interstellar distances, even the shortest; why would their signals be any different? But if we could confine a signal well enough, how do we know which way to point it?

[EdEarl]

 

 

But why? Any signal we send out, however strong and confined must diverge and thus weaken, over interstellar distances, even the shortest; why would their signals be any different? But if we could confine a signal well enough, how do we know which way to point it?

I don't know the technical details, but SETI seems to think they can receive signals from an alien civilization.

[studiot]

 

I don't know the technical details, but SETI seems to think they can receive signals from an alien civilization.

 

 

Would Montezuma have recognised flashes from a heliograph as a signal?

 

And what would he have made of signals from a Napoleonic semaphore?

[Boxy Brown]

 

Would Montezuma have recognised flashes from a heliograph as a signal?

 

And what would he have made of signals from a Napoleonic semaphore?

 

 

If you take any culture that is both superstitious and keen observers, does it make sense to think they wouldn't recognize these as an attempt to communicate? If they noticed it (and somone flashing bright light at you is hard to miss), it would attract their attention, and a short repeated message doubly so. I would be surprised if they didn't try to investigate the source, or didn't think someone or something was trying to send them a message. If you thought novae and comets were signs from the gods, what would you make of a structured series of flashes?

 

If you are trying to communicate with the unknown, you don't try to hide or obfuscate your message. You add enough structure and order to make it impossible to mistake it as noise or a natural phenomenon. The recipient may not be able to decipher it, but the important information is knowing a message was sent at all.

 

As for the climate change hypothesis, I wonder if this only puts an upper limit on the star size we associate with a possibility for life. Most of the stars out there are smaller than ours, and their evolution is stretched over a longer period of time. I'm not an astronomer, but I would assume that means that the increase in insolation on any orbiting planet would take longer as well. It probably isn't linear, so a marginally smaller star, like Tau Ceti (80% of the Sun's mass) might take a much longer time to cook it's habitable planets.

 

Perhaps it's a dangerous galaxy and no one wants to be heard. I suddenly feel like watching Independence Day ;-)

[EdEarl]

 

Perhaps it's a dangerous galaxy and no one wants to be heard. I suddenly feel like watching Independence Day ;-)

I'd say the probability is high that it is a dangerous Universe. However, Your implication seems to be it is better to be stealthy than loud, because someone is listening and might invade us, which IMO seems unlikely. For one thing, the Universe is dangerous and not well suited for biological organisms. Secondly, the Universe is large, and resources are everyone; there is no reason to fly thousands of light years, through an environment that can kill you, to steal resources. It is much easier to mine asteroids or planets in your own system.

[studiot]

 

but the important information is knowing a message was sent at all.

 

Yes indeed, that was my point. So what about my second example?

 

As to the heliograph you would still have to look to see the flashes and know where to look. Perhaps this was not such a good example because I think that simple heliographs went back to Alexander so actually predated Monte. However the person communicating was trying to communicate with his friend not me or to make a general broadcast.

Perhaps the aliens, if they exist, are communicating with each other but not directing their space-graphs at us.

[Strange]

Perhaps technology development by intelligent life is an exceptionally rare event.

 

Given the title, I thought you were going to suggest that technology development is common but almost inevitably brings about the collapse of the societies that develop it.

 

Given the rate of progress in detecting exo-planets, I wonder how long it will be before we can detect the (artificial) satellites orbiting some of these planets. (Only partly tongue in cheek.)

[EdEarl]

The history of bandwidth is of interest in this discussion. The first spark gap transmitters used much bandwidth, but inefficiently. Tuned bandwidths cam next, but long wave because antennas were easy to make and long distance communication was possible to many people. Longwaves are used mostly by AM radio and HAM operators. There are still a few open channel AM radio stations that crank up their power at night, when conditions are good for long distance communications, and they transmit up to 0.5 MW of power on that channel. Additional bandwidths are opened by the FCC as technology improves, and the frequency of radio equipment extends to additional frequencies, in particular higher frequencies as FM, television, cell phones, and other radio frequency devices. All these bandwidths continue to be used, and there are no plans for discontinuing use of a frequency domain AFAIK.

I would expect a similar experience by any technological society.

[Boxy Brown]

there is no reason to fly thousands of light years, through an environment that can kill you, to steal resources. It is much easier to mine asteroids or planets in your own system.

 

Perhaps, but it might make sense to travel ten light years to acquire resources. You might not even send people out to collect them. Perhaps you send out robotic missions that send the materials back here. If you had the technology to accelerate to ten percent of the speed of light, you would begin receiving resources within a century ( I'm assuming travel to our nearest neighbour here, 4ish ly away).

 

Over the past century, our population and our dominion over this planet have grown exponentially. As we deplete the resources on Earth and as technology advances, there will come a point where exploiting the materials in the rest of the solar system will be as profitable as exploiting the remaining resources on earth. If our growth continues as it has in the past, we would consume the resources in the rest of the solar system relatively quickly, and get to the point where exploiting the resources in the next star system over is as profitable as those remaining in the solar system.

 

Relative to the current age of the galaxy, it wouldn't take long for a species like ours to spread across the galaxy. The Independence Day reference was tongue in cheek, although if you've traveled across ten light years to get something your species needs, maybe you're less inclined to share!

 

I believe that given our insistence on perpetual growth, our curiosity, and there always being a few individuals willing to take great risks, we will eventually try to leave our home. Why not others?

 

But that is the paradox I guess. Obviously there is something wrong with this scenario. There are so many possibilities to explain it too, that it's a lot of fun to speculate. We won't know for sure until we expand and/or meet our neighbours, find we can't or shouldn't expand at all, or occupy an otherwise empty galaxy. I just hope I live long enough to see the first interstellar probes start sending back data.

 

(and the Voyagers don't count... I want pictures from the next system over!)

[MonDie]

[snipped]

 

Perhaps the aliens, if they exist, are communicating with each other but not directing their space-graphs at us.

... and every lifeform that sent a signal for all was thereafter enslaved, hence their signal died.

Edited June 18, 2014 by MonDie

[dimreepr]

...

[Hazel M]

And, if there is intelligent life "out there", when we land and start taking whatever we want, they may just blow us to bits, no questions asked.

[MonDie]

Maybe they're using a signal medium that's still unkown to us. They understood ???? waves before they understood electromagnetic radiation because ???? waves are what their sensory organs responded to.

Edited June 21, 2014 by MonDie

[Sensei]

 

But why? Any signal we send out, however strong and confined must diverge and thus weaken, over interstellar distances, even the shortest; why would their signals be any different? But if we could confine a signal well enough, how do we know which way to point it?

 

Yeah.

 

If somebody tried to calibrate satellite dish & receiver from Astra or Hot Bird, he should know how hard it is.. I really hate doing it. 1mm in wrong direction and there is no transmission.

 

It's plain stupid to send signal for longer distances in the all directions (following inverse square law). It would waste a lot of energy to send data where is nobody who can listen for signal.

When we're sending data (and receiving data back) to/from Voyager it's directional signal, like laser, very precisely adjusted to target. And we don't send signal to place where Voyager is now visible, but where it'll be after time needed for signal to reach that location. Where is nothing now from our point of view.

 

Airplane pilots do the same- shooting at location ahead of enemy airplane.

http://en.wikipedia.org/wiki/Deflection_%28ballistics%29

Edited June 21, 2014 by Sensei

[Ten oz]

All known life on earth has DNA. We are still working out how basic chemicals mixtures formed DNA. Life elsewhere in the universe could be very different. With a reproduction coding other than DNA evolution may not be possible or it could be faster. Perhaps all life in the universe has DNA. It is seeding throughout the universe in asteroids. We just don't know. We have only set foot on the moon and sent probes to planets in our own backyard.

I also don't think we are advanced enough to interpret a message from other intelligent life. Any off world life form would have to learn our language, concepts of thought, and then send us a clear linear message. Reason I think that is because we live on a planet full of life and have not yet to learned to communicate with any of it. We have no idea what dolphins, chimpanzees, or any other animal thinks. Even when we see our own pets like the family dog or cat dreaming we have no idea what they would be dreaming about.

[Hazel M]

Ten oz, believe me. My cats never left any doubt in my mind as to what they were saying. But, nevermind that. Just a comment. I do understand what you are saying. You make a very good point. You have to crawl before you walk. How in the world do you keep up with it all? Don't you find it a fascinating study?

[MonDie]

All known life on earth has DNA. We are still working out how basic chemicals mixtures formed DNA. Life elsewhere in the universe could be very different. With a reproduction coding other than DNA evolution may not be possible or it could be faster. Perhaps all life in the universe has DNA. It is seeding throughout the universe in asteroids. We just don't know. We have only set foot on the moon and sent probes to planets in our own backyard.

 

Even something with DNA might use different amino acids.

 

There are 140 natural amino acids, of which only 23 are used in "translational machinery". - https://en.wikipedia.org/wiki/Non-proteinogenic_amino_acids

 

 

I also don't think we are advanced enough to interpret a message from other intelligent life. Any off world life form would have to learn our language, concepts of thought, and then send us a clear linear message. Reason I think that is because we live on a planet full of life and have not yet to learned to communicate with any of it. We have no idea what dolphins, chimpanzees, or any other animal thinks. Even when we see our own pets like the family dog or cat dreaming we have no idea what they would be dreaming about.

The question is whether we would recognize it as a (yet to be decoded) language.

 

I bet any lifeform that can use mental representations to model the world will at least utilize coherence, realizing that a concept's predictive value is inversely related to its contradictoriness to other predictive concepts. Their linguistic implementation of true/false, however, could be absolute or fuzzy (truthlikeness).

In addition, they'll probably utilize subjective vs. objective since communication between different perspectives requires translation between subjective (it looks red, it's in front of me, here and now, etc.) and objective: the apple (it) was emitting scattering 400-500nm light (red) at 03:42pm (now) in Austin, Texas (and here).

Edited June 23, 2014 by MonDie

[Ten oz]

Ten oz, believe me. My cats never left any doubt in my mind as to what they were saying. But, nevermind that. Just a comment. I do understand what you are saying. You make a very good point. You have to crawl before you walk. How in the world do you keep up with it all? Don't you find it a fascinating study?

It is very fascinating. Fortunately we don't have to keep up with it all on an individual level. Collectively we can process huge amounts of knowledge. All each of us have to do is small.

 

Even something with DNA might use different amino acids.

 

There are 140 natural amino acids, of which only 23 are used in "translational machinery". - https://en.wikipedia.org/wiki/Non-proteinogenic_amino_acids

 

 

 

The question is whether we would recognize it as a (yet to be decoded) language.

 

I bet any lifeform that can use mental representations to model the world will at least utilize coherence, realizing that a concept's predictive value is inversely related to its contradictoriness to other predictive concepts. Their linguistic implementation of true/false, however, could be absolute or fuzzy (truthlikeness).

In addition, they'll probably utilize subjective vs. objective since communication between different perspectives requires translation between subjective (it looks red, it's in front of me, here and now, etc.) and objective: the apple (it) was emitting 400+ nm light (red) at 03:42pm (now) in Austin, Texas (and here).

I understand your point of view but feel your confidence is overstated. You said you'd "bet" but how are you calculating the odds? It has never been done before. We can't say for sure it will ever be done. I personally think we will eventually discover life and intelligence elsewhere in the universe but won't bet on it. The odds are still very long.

[Sensei]

Reason I think that is because we live on a planet full of life and have not yet to learned to communicate with any of it. We have no idea what dolphins, chimpanzees, or any other animal thinks. Even when we see our own pets like the family dog or cat dreaming we have no idea what they would be dreaming about.

 

The question is whether we would recognize it as a (yet to be decoded) language.

For some signal types it's very easy.

 

For instance, put tiger to monkey's cage, and record sound they will be screaming. (Or record it in real wild world)

That's sound of "danger", "tiger", "run away", "enemy".

Recorded sound can be later used on different group of monkeys (same kind), or same group at different time (couple days, months, years later), to see whether they treat it the same way.

 

That reminds me Myth Busters that tried to see whether duck quack has echo. They took single duck, but he/she didn't wanted to quack

It took them some time to figure out they need two or more ducks.

Apparently single duck didn't want to talk to himself/herself..

What a surprise..

I bet any lifeform that can use mental representations to model the world will at least utilize coherence, realizing that a concept's predictive value is inversely related to its contradictoriness to other predictive concepts. Their linguistic implementation of true/false, however, could be absolute or fuzzy (truthlikeness).

In addition, they'll probably utilize subjective vs. objective since communication between different perspectives requires translation between subjective (it looks red, it's in front of me, here and now, etc.) and objective: the apple (it) was emitting 400+ nm light (red) at 03:42pm (now) in Austin, Texas (and here).

 

See this video:

 

Edited June 23, 2014 by Sensei

[Hazel M]

For some signal types it's very easy.

 

For instance, put tiger to monkey's cage, and record sound they will be screaming.

That's sound of "danger", "tiger", "run away", "enemy".

Recorded sound can be later used on different group of monkeys (same kind), or same group at different time (couple days, months, years), to see whether they treat it the same way.

 

That reminds me Myth Busters that tried to see whether duck quack has echo. They took single duck, but he/she didn't wanted to quack

It took them some time to figure out they need two or more ducks.

Apparently single duck didn't want to talk to himself/herself..

What a surprise..

<G>

[Tim the plumber]

 

Would Montezuma have recognised flashes from a heliograph as a signal?

 

And what would he have made of signals from a Napoleonic semaphore?

 

Those sort of signals tend to be obvious to all. Smoke signals can be understood as a signal without knowing what they say.

 

It's the modern digital signals which I think would be very difficult to identify if your reception equipment was not set up to receive at the correct frequency rate.

 

If ET talks too fast for us to distinguish separate signals we might be mistaking all that white noise for random nothingness when in fact it's all there for the listening.