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SETI - unjustified leap in reasoning?

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#1 Ira

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Posted 07 February 2013 - 11:51 PM

I was scanning the headlines and came across this wonderful one:

"Less Than 1% of Exoplanet Systems Have Intelligent Life, Researchers Say"

What a wonderful discovery, I thought. What have they found?

It turns out, they found nothing.

"A group of astronomers...used the Green Bank Telescope in West Virginia to look for intelligent radio signals from planets around 86 of stars where the Kepler mission has found transiting exoplanets. These specific targets were chosen because they had exoplanets in the habitable zone around the star and there were either five or more exoplanets in the system, or there was super-Earths with relatively long orbits."

They found nothing. No big surprise there. But they scientists concluded:
"We didn’t find ET, but we were able to use this statistical sample to, for the first time, put rather explicit limits on the presence of intelligent civilizations transmitting in the radio band where we searched,” said Andrew Siemion from UC Berkeley."

How is it possible using a statistical sample of just 86 stars, where the results were entirely negative, to put a lower bound on the statistical likelihood of extraterrestrial intelligent life?

"The researchers said these results allows them to put limits on the likelihood of Kardashev Type II civilizations... The team said that finding no signals implies that the number of these civilizations that are “noisy” in the 1-2GHz range must less than one in a million per sun-like star."

Isn't this like saying, We have looked at 86 birds and on the basis of that conclude Black Swans exist with a probability of less than one per million birds, although we have never seen a Black Swan before?

Am I missing something here?

The article and pointer to their paper here.

/Ira

#2 Jason H.

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Posted 08 February 2013 - 12:21 AM

So I take it from several sources, 86 star systems were not transmitting a signal of >1.2 megawatts directly at Earth in a narrow frequency bandwidth of ~670 MHz for an "Observation Time per Source 300s", some several hundred to several thousand years ago (the time the signal would have taken to travel to us)? If those same planets were looking back at us with the same criteria, they would not see receive a message either. And if they were pointing a laser at us or transmitting at 5 GHz, or started sending today or 1 million years ago, or any of the myriad so-called 'Fermi Paradox' counter-arguments, that would have been missed too (point being one can't rule out anything based on this limited data set except for maybe the Kardashev Type II civilization they mentioned, but maybe the Kardashev II civilization's beacon's on a different frequency too, or their Klystron tube was busted, or their funding was cut and they didn't pay their electric bill, etc.? :)

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#3 Jarad

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Posted 08 February 2013 - 08:59 AM

I agree that they can't conclude much from that test.

On the other hand, I think that they are probably correct that intelligent life exists on less than 1% of planets... If I had to guess, I would be guessing several orders of magnitude lower than 1%...

Jarad

#4 Pess

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Posted 08 February 2013 - 11:12 AM

They make too many assumptions on too many variables.

I think the biggest assumption would be that once civilizations discover how to communicate with radio frequencies they will always radiate loudly in the radio frequencies.

That is like saying since we once communicated with Semaphores, the lack of Semaphore towers on a world indicates no intelligence.

Look at the Earth as a great example. We are rapidly going
Radio Dead' as more and more communication is reduced to fiber optics.

Reruns of I love Lucy are no longer being beamed into space at their previous levels, but instead are being tapped into and enjoyed by the Gopher & his family from Caddy Shack.....

Suppose the next step in communication involves FTL use of intertwined quarks or something? Radio frequency communication would become as quaint as using drums to communicate.

One thing about statistics, you can get them to say anything.

Pesse (78% of all statistics are made up on the spot) Mist

#5 Rick Woods

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Posted 08 February 2013 - 06:37 PM

If those same planets were looking back at us with the same criteria, they would not see receive a message either.


And, they would conclude there is no intelligent life here.

And they would largely be correct. :p

#6 llanitedave

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Posted 08 February 2013 - 10:03 PM

Sometimes I think the unintelligent life is more interesting anyway.

#7 Pess

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Posted 09 February 2013 - 04:58 AM

Sometimes I think the unintelligent life is more interesting anyway.


I guess intelligence is a very relative thing. My dog excels at being a dog but his cat imitation sucks.

I can't help but think that man in his present form will only be around a few thousand years and the reason we have not made alien contact yet is that, from their perspective, we are beneath notice and from our perspective it is like Christoffer Columbus trying to detect life in the New World by using technology available at the time from some beach in Spain.

There was a recent breakthrough in transplant rejection technology whereby donor stem cells are utilized to make the transplanted organ appear more 'self' to the organ recipient. This greatly decreases the need for anti-rejection meds.

I am sure technology will evolve to routine organ transplants and, from there, to artificial prosthesis for just about all body parts. A Total body prosthesis if you will

I just wonder, how will a TP being view a fragile nasty, smelly, inefficient bag of mostly water? With disdain?

What of sex when direct brain stimulation removes the requirement for EHarmony, Bud's bar and their associated mating rituals?

Will mankind disappear into a Matrix-like universe? Saw a patient the other day so addicted to an online game he spent most of his waking time playing it--and that's a simple 2-dimensional world!

Pesse (Back to PONG) Mist

#8 Mister T

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Posted 09 February 2013 - 08:36 AM

I am thinking that while physiological adaptations will be an important part of our evolutionary process, the more important changes will come in intelligence and empathy. we will need to "out grow" emotional responses such as disdain, greed, hate, and irrational fear. I highly doubt that any alien species advanced enough to discover us on our indiscreet blue marble, will still be shackled to primitive instincts. They will understand that they were once like we are, while not physically but psychologically.

The tremendous obstacles that are involved in interstellar communication and travel will not be overcome by ANY race that continues to rely on adrenaline and aggression and contempt for what it does not understand.

we've come a long way baby, but we ain't there yet! :fingerscrossed:

#9 Footbag

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Posted 09 February 2013 - 09:45 AM

If intelligent life was on anywhere near 1% of planets, I expect we would know it. If you define intelligent life as one which has the ability/desire to communicate with others, then that further pushes the threshold down.

I agree with Jarad that it's considerably less then 1%.

#10 Qwickdraw

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Posted 09 February 2013 - 10:25 AM

I am thinking that while physiological adaptations will be an important part of our evolutionary process, the more important changes will come in intelligence and empathy. we will need to "out grow" emotional responses such as disdain, greed, hate, and irrational fear. I highly doubt that any alien species advanced enough to discover us on our indiscreet blue marble, will still be shackled to primitive instincts. They will understand that they were once like we are, while not physically but psychologically.

The tremendous obstacles that are involved in interstellar communication and travel will not be overcome by ANY race that continues to rely on adrenaline and aggression and contempt for what it does not understand.

we've come a long way baby, but we ain't there yet! :fingerscrossed:


That said it is largely social behaviors like war, greed, mistrust and envy that have driven many of the leaps we see into space exploration, propulsion systems, optical and electronic surveillance etc.

#11 Pess

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Posted 09 February 2013 - 10:43 AM

I am thinking that while physiological adaptations will be an important part of our evolutionary process, the more important changes will come in intelligence and empathy. we will need to "out grow" emotional responses such as disdain, greed, hate, and irrational fear. I highly doubt that any alien species advanced enough to discover us on our indiscreet blue marble, will still be shackled to primitive instincts.


Greed & Motivation & Curiosity are also base emotions. How do you separate the wheat from the chaff?

Also, as Stephan Hawking pointed out, in the survival of the fittest the more aggressive race is going to likely rule the galaxy. The pacifists will be at the spaceports handing out flowers :grin:

Pesse (Sorry if I seem disdainful) Mist :jump:

#12 Mister T

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Posted 09 February 2013 - 11:29 AM

I forgot arrogance...

if we think that we can continue being a selfish, greedy aggressive race, we will never make it off this rock.

#13 llanitedave

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Posted 09 February 2013 - 11:21 PM

I can make one prediction with confidence:

Anything we predict here about our evolutionary future will be wrong.

#14 Ira

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Posted 10 February 2013 - 12:05 AM

I agree that they can't conclude much from that test.

On the other hand, I think that they are probably correct that intelligent life exists on less than 1% of planets... If I had to guess, I would be guessing several orders of magnitude lower than 1%...

Jarad


Here's my problem with their conclusion. I could just as easily say that the probability of a photon travelling faster than C is less than 50%. That's true, but misleading, because it's actually 0%. So they are passing off a conclusion that is entirely speculative as if it were conveying some new finding, which it isn't.

/Ira

#15 Rick Woods

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Posted 10 February 2013 - 02:49 AM

If intelligent life was on anywhere near 1% of planets, I expect we would know it. If you define intelligent life as one which has the ability/desire to communicate with others, then that further pushes the threshold down.

I agree with Jarad that it's considerably less then 1%.


Welllll....
It all depends on which end of the connection is intelligent, doesn't it?
Those desiring to communicate, and with the actual ability to do so, may be using technologies far beyond ours. So we would be the species too unintelligent to communicate.

I feel it very unlikely that we are the benchmark for technological intelligence.

Of course, I could be wrong.

#16 Jarad

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Posted 10 February 2013 - 11:41 AM

Here's my problem with their conclusion. I could just as easily say that the probability of a photon travelling faster than C is less than 50%. That's true, but misleading, because it's actually 0%. So they are passing off a conclusion that is entirely speculative as if it were conveying some new finding, which it isn't.



Like I said, I agree that you can't really draw much conclusion from the scant data they have. We have not observed even those few planets in enough detail to conclude that they do not have intelligent life. We can only say that we did not oberve any intelligent life transmitting in our direction with enough power for us to detect on the wavelengths we checked for the few seconds we were looking.

In other words, insufficient data.

But I still suspect that the real frequency is <<<1%. ;)

Jarad

#17 llanitedave

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Posted 11 February 2013 - 12:09 AM

I feel it very unlikely that we are the benchmark for technological intelligence.


Sure we are. We are our own benchmark, the only one that most of us are interested in.

#18 Rick Woods

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Posted 11 February 2013 - 01:46 AM


I feel it very unlikely that we are the benchmark for technological intelligence.


Sure we are. We are our own benchmark, the only one that most of us are interested in.


That sounds like something from Jungle Book! :) However, it's true; and when we compare ourselves to us, we always measure up.
But I meant the uber-benchmark, that all of the galactic community measures itself by. Us? I don't think so. But, it's possible I suppose.

And anyway, I want to know about the alien technology. How do they go so fast? How can they be so advanced, but they can't solve their drooling problem? Why do the insides of alien spaceships all look like something you'd see in a colonoscopy? Why do they abduct us and do their "probe" thing? What do they hope to learn from our butts? And why do they keep falling for the old let-all-the-air-out-of-the-ship trick?

These are important matters!

#19 Mister T

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Posted 11 February 2013 - 06:45 AM

Their Physics, engineering and Math departments get high marks and their Biology department fails!!!???

#20 Qwickdraw

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Posted 11 February 2013 - 06:49 AM

But I still suspect that the real frequency is <<<1%. ;)

Jarad


Jarad, I am curious if you feel the miniscule probability of intelligent life in the universe is more the result of lack of habitable planets, life forming on those planets or intelligent life evolving?

In other words, could you weight which ones you feel are more probable or less probable?

BTW, I agree with you entirely except I believe the probability may be so low that us Humans are the only intelligent life in the universe.

All of this said assuming the universe is not infinite which I believe is the accepted current model

#21 dickbill

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Posted 11 February 2013 - 10:09 AM

"...assuming the universe is not infinite..."

even if the universe is infinite, there might be only one occurence of Life, same as in the infinite suite of mumbers, there is only one number zero, and one number 1.

#22 Jarad

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Posted 11 February 2013 - 10:38 AM

Jarad, I am curious if you feel the miniscule probability of intelligent life in the universe is more the result of lack of habitable planets, life forming on those planets or intelligent life evolving?



Well, that's a good question.

Part of it is that we don't have a good grasp on what is required for a planet to be "habitable". Is just being in the "goldilocks zone" enough? Do you need a single large moon? Tides? Do you also need a Jupiter-like planet further out to vacuum up incoming impactors?

Given that you have all of the requirements to be "habitable", what are the odds of life evolving at all? The initial steps aren't well understood, we don't know how likely they are.

Once we get to a self-replicating cell, I think evolution will take over and we will get more advanced life. I think that will eventually include some level of intelligence. Whether it leads to technology or not I think is more questionable.

So I think there are a lot of unknown probabilities in the chain from planets to intelligent technological life. In order for intelligent technological life to be highly probably, all of those individual probabilities need to be high. If any are very low, then the over probability is very low. If several are just somewhat low, the overall probability still ends up very low (even 3 steps below 1% chance drops you down to less than 1 per million).

The universe is a big place, so I suspect that there is intelligent life elsewhere. But the universe is big place, so I am doubtful if we will ever run across it.

Jarad

#23 deSitter

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Posted 11 February 2013 - 12:39 PM

We don't have the slightest idea how abstract intelligence formed here - and so how can we assess the likelihood of it forming elsewhere? So it's totally idle speculation. We are just as likely to alone as not.

-drl

#24 Pess

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Posted 11 February 2013 - 02:20 PM

We don't have the slightest idea how abstract intelligence formed here - and so how can we assess the likelihood of it forming elsewhere? So it's totally idle speculation. We are just as likely to alone as not.

-drl


I don't necessarily agree with those that say life is unique to Earth. Or even intelligent life is unique to Earth. Even if single celled organisms only developed on one planet it should still end up distributed around the Universe by Panspermia.

Dunno. What I believe is that we will be so different than what we are today (as a defined intelligent species) that our future selves won't bother with our past selves.

Humans look at the vast interstellar distances and wonder how we can transverse them...much as our forefathers looked at the oceans.

But the problem is not one of only distance, but one of time as well. For a sentient being who lives millions of years the travel time becomes less daunting.

Pesse (Perhaps George Jetson and his family is scooting by our blue orb everyday..regarding it more as a quaint petting zoo than their equals.) MIST

#25 Qwickdraw

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Posted 11 February 2013 - 02:22 PM

We don't have the slightest idea how abstract intelligence formed here - and so how can we assess the likelihood of it forming elsewhere? So it's totally idle speculation. We are just as likely to alone as not.

-drl


If as you say "We don't have the slightest idea how abstract intelligence formed here" does not mean "We are just as likely to (be) alone as not.
It just means we still do not have the capability of making a reasonable determination which in no way can influence the likelihood.






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