60 years of silence - so far

[bilby]

F_l*F_i*F_c can be estimated based on the single datum we have for these probabilities on an earthlike planet - planet Earth.

Except that our existence is consistent with a very low value of that product -- we would then be very lucky to exist.

I'm not seeing a problem with that.

It's consistent with observation.

Winning the lottery is very unlikely. But lottery winners nevertheless exist, and can't reasonably use their incredible good fortune to question their own existence.

If our level of civilisation is very rare, then only on those planets which have it are there people who are able to wonder at the improbability of it.

 

[Jimmy Higgins]

F_l*F_i*F_c can be estimated based on the single datum we have for these probabilities on an earthlike planet - planet Earth.

Well, technically it'd be planet Earth and all the planets and moon in the solar system, minus the moons that might have some form of life on it... and Mars which might have had life on it.
F_l = 1/(278-6 or so) (odds increased when Pluto not a planet anymore )
F_i = 1/278
F_c = 0/278 (aw shit!)

 

[steve_bank]

Assignment of probabilities is subjective, as in Drake equation. It allows varying parameters to assess relative effects.

WAG Wild ass guess - pure guess work without foundation.
SWAG Scientific wild ass guess - a guess based on some knowledge and science, speculation. Or guesstimate.

I knew both terms, Scientific Wildly Aimed Guess is a new one for me, and IMO applies to eetmated occurence of ETs.

Scientific wild-ass guess - Wikipedia

en.wikipedia.org

SWAG is used to describe an estimate derived from a combination of factors including past experience, general impressions, and heuristic or approximate calculations rather than an exhaustive search, proof, or rigorous calculation. The SWAG is an educated guess but is not regarded as the best or most accurate estimate.[2] The SWAG is not computed or proven rigorously, but the proponent asserts his or her own judgement suffices to rationalize the estimate; and it may, in time, be viable to produce a rigorous forecast of increased precision.[6]

Various other backronyms of SWAG have been published, including "sophisticated wild-ass guess", "Silly Wild-Ass Guess", "Semi-Wild-Ass Guess", "Stupid Wild-Ass Guess", and "Scientific Wildly Aimed Guess".[7] "Scientific" implies that the "guess" can be justified if necessary or cost-effective.[3] A guess of lesser worth may be called the "Wild-Ass Guess" or "WAG". A slightly better estimate may be called "Back of the Envelope" (BOTE).[8]

 

[lpetrich]

F_l*F_i*F_c can be estimated based on the single datum we have for these probabilities on an earthlike planet - planet Earth.

Well, technically it'd be planet Earth and all the planets and moon in the solar system, minus the moons that might have some form of life on it... and Mars which might have had life on it.
F_l = 1/(278-6 or so) (odds increased when Pluto not a planet anymore )
F_i = 1/278
F_c = 0/278 (aw shit!)

Where do those numbers come from?

 

[Jimmy Higgins]

F_l*F_i*F_c can be estimated based on the single datum we have for these probabilities on an earthlike planet - planet Earth.

Well, technically it'd be planet Earth and all the planets and moon in the solar system, minus the moons that might have some form of life on it... and Mars which might have had life on it.
F_l = 1/(278-6 or so) (odds increased when Pluto not a planet anymore )
F_i = 1/278
F_c = 0/278 (aw shit!)

Where do those numbers come from?

Planets and moons in our solar system. We know life likely hasn't existed on most of it. We know intelligent life is almost certainly never existed on most of it. And we know inter-galactic communication hasn't been achieved on any of it.

 

[lpetrich]

Take another look at the Drake equation. f_l is for the origin of life on *Earthlike* planets, and there is exactly one in the Solar System: the Earth itself. f_i is for the origin of intelligence when life has originated, and f_c is for the origin of interstellar communicative ability when intelligence has originated.

Thus, it is irrelevant what the total number is of planets and moons.


Written with subscripts, the Drake equation is

N = R_s * f_p * n_e * f_l * f_i * f_c * L

 

[pood]

There could be any number of planets out there with human-level intelligence but little or no advanced technology, just like us for almost our entire history. One hundred fifty years ago we didn’t even have telephones! Our most advanced communication tech was the telegraph.

 

[steve_bank]

I only have an overview of the entire process as imagined going back to the first imagined self replicating organisms in early ocean.

How the O2 atmosphere developed. A strike that created the moon. The Yucata strike.

If Tunguska and Yucatan had occurred at different places and times would humans have evolved?

As a set of serial probabilities the probability of human life or similar variations is low.

Scifi abounds with variations in life. For technology to arise requires a brain wired a certain way, mobility, an articulate form of communication, and dexterity. Tool making.

Brains, mobility, and dexterity abound on the planet, but the human form has the right balance.

Given all the potential variables I just don't see how meaningful probabilities can be developed.

Radio as we know it requires silicon and an array of other materials and chemicals to make trasistors.

Do we know for sure what the distribution and density would be of the materials in another solar system on a planet in the Goldilocks Zone?

It is not just a probabilty that is required, distributions are required.

 

[Loren Pechtel]

The question is, how much longer will this ability persist? If the answer is "less than several orders of magnitude as long as it has existed so far", then the probability of detecting another intelligent life form must be very low; We would expect maybe a thousand in the entire galaxy, and the chances of any being within the 100ly or so necessary to detect us (and therefore to be detectable by us) is tiny.

And radio is already way past its peak. It's rapidly becoming a rare, niche, technology, with few powerful signals being sent (deliberately or accidentally) into space. The vast majority of our communications is moving to landlines or very short range, low-power, radio.

The answer to the Fermi paradox is likely that radio broadcasting life is very uncommon. After all, radio broadcasting life occupies a minuscule fraction of the timeline of the one planet that we know for certain has life capable of producing those signals.

This assumes intelligent civilizations will never engage in interstellar colonization.

 

[Loren Pechtel]

Finally, the lifetime of a communicating civilization, L. There are numerous factors that can limit it:

• War
• Environmental Problems
• Resource Depletion
• Disease
• Social / Political / Economic Collapse
• Technological Failure
• Loss of Interest

I'm not very willing to speculate about them.

But I note that the rarity solution of the Fermi paradox is sometimes called some  Great Filter -- something or other makes the emergence of communicative civilizations *very* rare.

In the evolution of life on our planet, there are several events that happened only once, like the origin of life, the origin of oxygenic photosynthesis, and the origin of animallike multicellularity. If these events are very improbable, then we would be very lucky to come into existence.

Note that the filter need not be in the past. A universally low L would explain it--civilization is inherently destructive.

 

[Loren Pechtel]

F_l*F_i*F_c can be estimated based on the single datum we have for these probabilities on an earthlike planet - planet Earth.

Except that our existence is consistent with a very low value of that product -- we would then be very lucky to exist.

Observer effect--if it's a quadrillion to 1 against making it as far as we have the other 999 trillion planets don't have observers to note the failure.

The only thing we can conclude about probabilities from looking at our past is how long the various steps took. We know the step from life to multi-cellular life took about half of the available time and the step from multi-cellular life to tool-users likewise took about half the available time. However, life arose fast--it's probably easy and not the bottleneck. Suitable planets don't seem to be too common, but given the gamut we see in the skies there should be a reasonable number--likewise, not the bottleneck.

Either we got horrendously lucky in one of those steps (life->multicellular or multicellular->tool user) or the filter is in front of us--and if it's front of us it's something we bring about as nature couldn't reliably destroy planets at just the right point.

 

[pood]

The only thing we can conclude about probabilities from looking at our past is how long the various steps took. We know the step from life to multi-cellular life took about half of the available time and the step from multi-cellular life to tool-users likewise took about half the available time. However, life arose fast--it's probably easy and not the bottleneck.

I don’t think we can conclude anything from the probabilities from one data point. Could be that on other planets, life arises late but multicullularity and tool users arise relatively quickly after that.

 

[Elixir]

I see no fundamental dividing line between tools and food. Nutrients are tools of metabolism, and tool use is endemic to life. Technological “Civilizations” behave similarly in collective. They devour the earth and everything it supports to enhance the reproductive success (wealth) of their individuals.

 

[barbos]

There are no aliens in our galaxy:

 

[bilby]

The question is, how much longer will this ability persist? If the answer is "less than several orders of magnitude as long as it has existed so far", then the probability of detecting another intelligent life form must be very low; We would expect maybe a thousand in the entire galaxy, and the chances of any being within the 100ly or so necessary to detect us (and therefore to be detectable by us) is tiny.

And radio is already way past its peak. It's rapidly becoming a rare, niche, technology, with few powerful signals being sent (deliberately or accidentally) into space. The vast majority of our communications is moving to landlines or very short range, low-power, radio.

The answer to the Fermi paradox is likely that radio broadcasting life is very uncommon. After all, radio broadcasting life occupies a minuscule fraction of the timeline of the one planet that we know for certain has life capable of producing those signals.

This assumes intelligent civilizations will never engage in interstellar colonization.

Sure.

Which, given the expense and futility of such an endeavour due to the speed of light, is a very reasonable assumption.

Interstellar colonisation sounds good in science fiction, but it's not practical or plausible without faster than light travel, or at least faster than light communications, neither of which is likely to be possible.

 

[Jimmy Higgins]

The question is, how much longer will this ability persist? If the answer is "less than several orders of magnitude as long as it has existed so far", then the probability of detecting another intelligent life form must be very low; We would expect maybe a thousand in the entire galaxy, and the chances of any being within the 100ly or so necessary to detect us (and therefore to be detectable by us) is tiny.

And radio is already way past its peak. It's rapidly becoming a rare, niche, technology, with few powerful signals being sent (deliberately or accidentally) into space. The vast majority of our communications is moving to landlines or very short range, low-power, radio.

The answer to the Fermi paradox is likely that radio broadcasting life is very uncommon. After all, radio broadcasting life occupies a minuscule fraction of the timeline of the one planet that we know for certain has life capable of producing those signals.

This assumes intelligent civilizations will never engage in interstellar colonization.

One minor issue with interstellar colonization is it is a death trap and very pointless. Everyone talks time, but what about energy, efficiency, and reliability? People hop onto generation ships and it all goes well. How unlikely is that? Much less than intelligent life out there. And for what purpose? Looking for planets that can be lived on that are likely very widely spaced apart, while already on a revolving sphere they were evolved to live on?!

And then there is the issue that this would be a permanent tiny splinter portion of our civilization which includes an issue for genetic diversity among other psychological issues.

It'd seem logical space living will be bound to Earth or Moon.

 

[steve_bank]

I heard somebdy on NOR talking about ts.

Scientists Have Founded a ‘Post-Detection Hub’ to Prepare for Alien Contact

“There will be denial/conspiracy advocates, as is the case for many events in history,” the organization's founder says.

www.vice.com

Scientists Have Founded a ‘Post-Detection Hub’ to Prepare for Alien Contact
“There will be denial/conspiracy advocates, as is the case for many events in history,” the organization's founder says.

Scientists have established a new research “hub” dedicated to preparing for the discovery of alien life, an event that would finally answer the age-old question of whether we are alone in the universe.

While it’s not clear that we will ever find life beyond Earth, or that aliens exist at all, the consequences of finding extraterrestrials would have immense and dizzying implications for humanity no matter what form it might take. The search for extraterrestrial intelligence (SETI)—along with the broader quest to find even simple forms of life, like bacteria—has become extremely sophisticated, raising the odds that we might actually stumble across evidence of aliens in the coming decades, assuming it is really out there.

John Elliott, who serves as honorary research fellow in the School of Computer Science of the University of St Andrews in Scotland, has been thinking about the potential ramifications of an alien detection for decades. During his long involvement with the SETI Permanent Committee, a group of SETI experts established by the International Academy of Astronautics (IAA), he has developed approaches for deciphering extraterrestrial messages and gamed out how to disseminate information about a confirmed extraterrestrial detection to a global audience.

Now, Elliott has founded the SETI Post-Detection Hub, hosted by the University of St Andrews’ Centre for Exoplanet Science and the Centre for Global Law and Governance, to bring together diverse experts and anticipate the joys and tribulations of a post-detection world.

“It was increasingly evident that we needed a center (home) to coordinate our efforts for an integrated provision to deal with such an event,” Elliott told Motherboard in an email. “So, with the encouragement of colleagues, I took the initiative and began developing the hub, to where it is now.

Reports like this and as on the radio show preface it all with the word scintists implying autherticity.

 

[steve_bank]

Possible ET messages, assuming ET is 'intelligent' as we see it.

Surrender or die!
ET1 God exists.
ET2 god does nor exist.
We had a natural disaster send help.
We are plagued with wars and political unrest, how did you solve your problems.
Mary's brothel and casino open all the time, we validate space dock parking fees for customers.
Joe's gun shop, discount atomic weapons
Our borders are closed. Keep out. Trespassers will be shot.

 

[Loren Pechtel]

The only thing we can conclude about probabilities from looking at our past is how long the various steps took. We know the step from life to multi-cellular life took about half of the available time and the step from multi-cellular life to tool-users likewise took about half the available time. However, life arose fast--it's probably easy and not the bottleneck.

I don’t think we can conclude anything from the probabilities from one data point. Could be that on other planets, life arises late but multicullularity and tool users arise relatively quickly after that.

The thing is, why would we be abnormal?

Life on Earth arose as early as it was possible for life to survive, to the admittedly limited accuracy possible that far back. If you figure it's a statistical process you figure it shouldn't be way out on a tail. You don't have to go nearly so far out on tail for one for the slow steps to be the culprit. We are looking for something in the billions-to-one range. If it's life arising then you're looking at tens of billions to one. Which is more likely?

As grim as it looks (the filter is probably in our future) I see one substantial bit of hope: We have already used 99% of the available time on Earth to get to this point. Chance? Or does that mean the process of becoming an interstellar civilization simply takes too long in the vast, vast majority of cases--the planet becomes uninhabitable before they reach the tool using state.

(Yeah, life on Earth doesn't vanish 50 million years from now, but the climate thermostat will peg and the temperature will start creeping up. Evolution will favor organisms with fast life cycles that can adapt faster.)

 

[Loren Pechtel]

The question is, how much longer will this ability persist? If the answer is "less than several orders of magnitude as long as it has existed so far", then the probability of detecting another intelligent life form must be very low; We would expect maybe a thousand in the entire galaxy, and the chances of any being within the 100ly or so necessary to detect us (and therefore to be detectable by us) is tiny.

And radio is already way past its peak. It's rapidly becoming a rare, niche, technology, with few powerful signals being sent (deliberately or accidentally) into space. The vast majority of our communications is moving to landlines or very short range, low-power, radio.

The answer to the Fermi paradox is likely that radio broadcasting life is very uncommon. After all, radio broadcasting life occupies a minuscule fraction of the timeline of the one planet that we know for certain has life capable of producing those signals.

This assumes intelligent civilizations will never engage in interstellar colonization.

One minor issue with interstellar colonization is it is a death trap and very pointless. Everyone talks time, but what about energy, efficiency, and reliability? People hop onto generation ships and it all goes well. How unlikely is that? Much less than intelligent life out there. And for what purpose? Looking for planets that can be lived on that are likely very widely spaced apart, while already on a revolving sphere they were evolved to live on?!

And then there is the issue that this would be a permanent tiny splinter portion of our civilization which includes an issue for genetic diversity among other psychological issues.

It'd seem logical space living will be bound to Earth or Moon.

I think we will extend lifespan.

And look in the mirror. We are here because people didn't like Europe and wanted to go elsewhere. I think interstellar colonization will happen the same way--people wanting to set up societies they see as better.