Likelihood of receiving ET signals

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Profile William Rothamel
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Message 1951785 - Posted: 24 Aug 2018, 12:16:36 UTC - in response to Message 1951760.  
Last modified: 24 Aug 2018, 12:22:04 UTC

is repeatable and not of artificial origin


There is the possible cause for our current failure to detect. --I am referring to the word "repeatable".
Any contact is most likely to be a one-time focused beam that is randomly fired at positions in the sky.

Our own message was a one-time affair.

The repeatable nonsense implies eavesdropping on a nearby civilization. 50 years, very few stars within 100 to 1000 light years no truly habitable planets yet found anywhere should put the lie to eavesdropping on the "Billions of Civilizations of which the Galaxy is teeming"

If we get and record a true 'we are here' type of contact--it will likely be from thousands of light years away and will simply and wonderfully confirm that we are not alone in the Cosmos as sentient and highly intelligent beings.
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Message 1951811 - Posted: 24 Aug 2018, 15:12:34 UTC - in response to Message 1951800.  

There are only 512 known stars within 100 light years of earth, which basically was my original point made here which was that, space is a damn sight bigger than people realise, so no I don't believe that the universe is teeming with life.
Yes.
Only 512 G-type main-sequence stars like our sun within 100 light years...
There are probably many more stars of other types like yellow dwarfs, orange dwarfs, red dwarfs, and white dwarfs,
But that those stars should have planets with life are considered unlikely.
But I have read that the SETI Institute tries to detect radio signals even 1400 light-years away.
https://www.seti.org/seti-institute/mysterious-star-kic-8462852
So perhaps its about 14 times more stars to listen to.
Still that is a very small fraction of the Milky way.

Btw. Our space is very empty. And contains only about 2 atoms per cubic meter on average.
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Message 1951822 - Posted: 24 Aug 2018, 15:52:54 UTC - in response to Message 1951800.  


Our own message was a one-time affair.

In terms of the Pioneer plaques there were two of them in 1972 and 1973. As far as I'm aware there has never been any international agreement that the earth should broadcast a "we are here signal".



i agree that our own signal was a one time affair and even if there would be someone on the way, since it is a one time affair, they would never discover us if they do same as us. they would receive a wow signal that would never have been repeated. and seeding 1 time affair to stupid target didnt help.

if you want any chance of a result, you need repeatable everyday to the 100 closest stars (and dont forget to count and correct the trajectory remembering in X light years takes X year to get there and the stars would have moved of X UA miles in certain directions)

and you need to think the aliens do the same in our direction, everyday, because we dont know what to do with a stupid wow signal that happended once in our lives.



There are only 512 known stars within 100 light years of earth, which basically was my original point made here which was that, space is a damn sight bigger than people realise, so no I don't believe that the universe is teeming with life.


yes the galaxy is filled of life ! Life can start everywhere in the galaxy. it is just everything are so far apart of each other. and this big interstellar space is a real cage preventing meetings.
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Message 1951825 - Posted: 24 Aug 2018, 16:03:54 UTC

I think the likelihood that we will detect a communication signal directed at us from an inhabited planet or a relay sitting in interplanetary space is not high on the probability scale. I remember though when I first saw the Drake equation the estimated percentage of stars with planets was well below 10%. That figure, according to the scientists who discuss these things on television programming regarding ET is now estimated to be much higher. Even so, space is a mighty big place, quoting Jodie Foster in "Contact". If contact does happen while I'm still alive I will die a happier man, but by now after 20 years of seti@home I have my doubts about whether that event will occur while I'm around to appreciate it. I saw reference to another type of possibility which would indicate the presence of ET and that would be detecting the exhaust plume of ET's space vehicle. Of course, it is impossible to say in advance how far out the drive exhaust of a space vehicle can or could be detected.
Bob DeWoody

My motto: Never do today what you can put off until tomorrow as it may not be required. This no longer applies in light of current events.
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Message 1951826 - Posted: 24 Aug 2018, 16:06:46 UTC

and probably, we dont even know how an alien signal should be! we imagine that is supposely a specific range of Hz. and what if it is really what we dont expect ? what if we totally wrong ?

how many of you , with all those UFO sightings, are adept of "I Want to Believe" ? if they are really here... dont you think they arent communicating with their mother planet at all ?
If they are really here, do you think they will never send back and forth any word ? for thousands of year ? totally disappear from their Mother Planet civilizations ? vanished ?

if they would be here, they are certainly communicating daily or weekly ! and why we dont even catch anything back and forth ? maybe we dont even know what is a signal and what range we need to search.
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Message 1951828 - Posted: 24 Aug 2018, 16:13:34 UTC - in response to Message 1951825.  
Last modified: 24 Aug 2018, 16:14:52 UTC

I think the likelihood that we will detect a communication signal directed at us from an inhabited planet or a relay sitting in interplanetary space is not high on the probability scale. I remember though when I first saw the Drake equation the estimated percentage of stars with planets was well below 10%.


ya i remember that false equation. we all know today that maybe every sun in this universe have 98% chance to have like 1 , 2 , 4, 6 , X planets around them.
We thought back that day a sun would rarely have planets. But thats the opposite, EVERY sun have something turning around them. even if it is just gas... or asteroids... or planets.... it is only a matter of time. if they are too young it is only gas... but eventually with time they will have planets.

so at the base, that Drake equation is wrong.
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Message 1951847 - Posted: 24 Aug 2018, 17:07:08 UTC - in response to Message 1951828.  

Hmm... The Drake equation is useless.
N = the number of civilizations in our galaxy with which communication might be possible when these terms are multiplicated:
R∗ = the average rate of star formation in our galaxy
fp = the fraction of those stars that have planets
ne = the average number of planets that can potentially support life per star that has planets
fl = the fraction of planets that could support life that actually develop life at some point
fi = the fraction of planets with life that actually go on to develop intelligent life (civilizations)
fc = the fraction of civilizations that develop a technology that releases detectable signs of their existence into space
L = the length of time for which such civilizations release detectable signals into space

Well, R∗, fp and ne are terms that scientists perhaps now have a rough idea what it could be.
The other terms are totally unknown.
So far we only know for fact is that N = 1, or perhaps N >= 1.
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Message 1951868 - Posted: 24 Aug 2018, 19:03:40 UTC

The only difference between this and this is the titles as both require contact.
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Profile William Rothamel
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Message 1951872 - Posted: 24 Aug 2018, 19:23:56 UTC
Last modified: 24 Aug 2018, 19:36:24 UTC

Well the Institute of Physics disagrees with you and so do I.

Your exception has been noted.

If we were spotted, then the hello signal might very well be repeated until we pull our head out and decode it. I am thinking right now that we have spotted no one and I presume they haven't spotted us. I do think that we should send our own Hello message to nearby stars--it doesn't have to be only once.

I fancy that a true contact might just be a beacon that slews its message around to all directions and may not be repeated in our direction if it is truly narrow band.

I was also referring to the almost 500KW signal that we blasted toward a far-away galaxy from Arecibo some years back. it was not repeated to the best of my knowledge
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Message 1951873 - Posted: 24 Aug 2018, 19:34:27 UTC
Last modified: 24 Aug 2018, 19:54:07 UTC

so at the base, that Drake equation is wrong.


I prefer the Rothamel Equation:

(% of stars that are main sequence) x (% of those with planets in a temperate zone) x (%of those planets that have near circular orbits) x (% having an atmosphere containing O-2) x (%that have a magnetic field) x (% that have abundant water and dry land) x (% of those having a stabilizing moon) x (% that have gravity within a narrow range) x (% of those that have an Ozone layer) x all of the other requirements for intelligent life similar to ours to start and evolve.

Right now I abhor the uncertainty of all of these factors--none-the-less--it's not looking good for billions of civilizations in the Galaxy. Stick your numbers or guesses in my equation above--if you come up with, say, 1 in ten million then you are too optimistic in your estimates. I, myself, will go with my gut feeling of maybe 5 civilizations in the Galaxy-possibly 30,000 light years between them or more.
not ashamed to be ignorant but worry that we won't answer these questions with any more precision any time soon.

Rebuttals welcome !!
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Message 1951907 - Posted: 24 Aug 2018, 22:56:18 UTC - in response to Message 1951873.  
Last modified: 24 Aug 2018, 23:09:15 UTC


I prefer the Rothamel Equation:

(% of stars that are main sequence) x (% of those with planets in a temperate zone) x (%of those planets that have near circular orbits) x (% having an atmosphere containing O-2) x (%that have a magnetic field) x (% that have abundant water and dry land) x (% of those having a stabilizing moon) x (% that have gravity within a narrow range) x (% of those that have an Ozone layer) x all of the other requirements for intelligent life similar to ours to start and evolve.


i think there are some "levels" or "items" are there only for trying to reduce the numbers.
or maybe some item is trying to make a more "precise" result at the end. those one would need to be a value similar of a 90% which doesnt play much at the end.

(% of stars that are main sequence) : ok. i am ok with this.

x (% of those with planets in a temperate zone) : shouldnt be there a x(%of those stars have some planets) which probable is 90%+ as we know today? so how would be a % of stars with at least 1 in godilock (tempererate zone)?

x (%of those planets that have near circular orbits) : really ? i would rather think they are never perfect (like our in our system) but can be much higher than we have. we have some planets that has a very oval circle but they are extremly far from the sun. it is possible to have a Mars going from where it is to closer to the sun as mercury ? yeah i guess possible. how much % it worth ?

x (%that have a magnetic field) : yeah important !

x (% having an atmosphere containing O-2) and x (% that have abundant water and dry land) : euh... if there is water, is it possible to not have some O2 in the atmosphere ? I know Mars has some kind of iced water but if smelt and gasified by the sun.... it release some kind of H2O in the atmosphere. i know mars doesnt hold its atmosphere or weak..... and the opposite possible ? to have O2 in atmosphere but no water ? cannot a life develop without O2 ?

x (% of those having a stabilizing moon) : thats probably important but if we look at our system... how many planet doesnt have a moon ?. having or not having a moon is it not related to the distance of its sun the planet is ? Mercury none... Venus none... both very near and not even reached the godilock zone.... Earth has one.... Mars further has two.... Jupiter has hundreds.. .Saturn has hundreds... Uranus tons of moons... So can a planet enough far from its sun have no moons ?

....

edit: wasnt possible Mercury was a Venus Moon at begining but cause it is too near from the sun, the sun stole it ?
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Profile William Rothamel
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Message 1951935 - Posted: 25 Aug 2018, 2:00:15 UTC
Last modified: 25 Aug 2018, 2:55:28 UTC

Addendum.

x (% of those that have a large gas giant outbound to absorb collisions) x (% of those those that have an axis tilt to provide seasons) x (% of those that have been planets for a few million years). Without adding any other conditions which may be necessary (such as notions of "contemporaneous" existence time lines--adjusted for distance ) you should be estimating about 4 in a billion or so. I still will stick with my 5 civilizations in the Galaxy which I claim is no more uncertain than any other estimate.
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Message 1951937 - Posted: 25 Aug 2018, 2:17:16 UTC - in response to Message 1951907.  
Last modified: 25 Aug 2018, 2:20:36 UTC

i think there are some "levels" or "items" are there only for trying to reduce the numbers.


let those exo-biologists who are far more qualified and better paid than I step forward and say which of my conditions are unnecessary or redundant and also let them add the ones I missed possibly relating to amino acids and maybe trans-spermia. Perhaps there is intelligent life on a level with humans in the oceans of moons that are heated by gravitational squeezing or vulcanism who somehow can communicate under water and across the cosmos.
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Message 1951979 - Posted: 25 Aug 2018, 12:50:00 UTC - in response to Message 1951935.  

correction; A few Billion years aging on a planet i.e. 10^9 for you all across the pond
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Message 1951982 - Posted: 25 Aug 2018, 14:01:31 UTC - in response to Message 1951979.  

correction; A few Billion years aging on a planet i.e. 10^9 for you all across the pond


in fact.... you can skip the stars equation and jump right away to the number of planets in godilock zones
https://www.nasa.gov/feature/ames/kepler/moreplanetsthanstars
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Message 1951984 - Posted: 25 Aug 2018, 14:30:01 UTC - in response to Message 1951982.  

correction; A few Billion years aging on a planet i.e. 10^9 for you all across the pond

in fact.... you can skip the stars equation and jump right away to the number of planets in godilock zones
https://www.nasa.gov/feature/ames/kepler/moreplanetsthanstars

But how many planets can a goldilock zone host?
Here both Venus and Mars failed to be host of life.
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Message 1952022 - Posted: 25 Aug 2018, 18:02:23 UTC
Last modified: 25 Aug 2018, 18:07:25 UTC

You definitely know the stuff here, Chris, and also how to write, but perhaps tell me in which way we are supposed to prove, for next only making it the Goldilocks zone.
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Message 1952033 - Posted: 25 Aug 2018, 18:52:35 UTC - in response to Message 1951984.  


But how many planets can a goldilock zone host?
Here both Venus and Mars failed to be host of life.


i guess 1 per star :)
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Message 1952042 - Posted: 25 Aug 2018, 19:48:12 UTC - in response to Message 1952033.  
Last modified: 25 Aug 2018, 19:48:23 UTC


But how many planets can a goldilock zone host?
Here both Venus and Mars failed to be host of life.


i guess 1 per star :)

We aren't donr looking on Mars and we just wrote off Venus without looking.
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Message 1952044 - Posted: 25 Aug 2018, 19:57:12 UTC

In order to play devil's advocate I submit the zones we are looking at are for water based life and dismiss the possibility of life based on something else.
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