Earth-like Planets Very Close & Number In The Billions

[Michael Allen]

From what I understand, SETI can only detect arbitrary radio transmissions (i.e. transmissions not necessarily directed at the earth intentionally) from about 0.3 LY distance

SETI estimates, for instance, that with a radio telescope as sensitive as the Arecibo Observatory, Earth's television and radio broadcasts would only be detectable at distances up to 0.3 light years.

Wikipedia - "Fermi Paradox"

So even if there is a civilization in the local solar neighborhood going through what ours did in the last century with regard to technology, we would be unable to detect it unless they intentionally directed a narrowband signal toward us.

 

[stonehart]

From what I understand, SETI can only detect arbitrary radio transmissions (i.e. transmissions not necessarily directed at the earth intentionally) from about 0.3 LY distance

Wikipedia - "Fermi Paradox"

So even if there is a civilization in the local solar neighborhood going through what ours did in the last century with regard to technology, we would be unable to detect it unless they intentionally directed a narrowband signal toward us.

That was my understanding of it as well, that this sort of detection took a directed transmission.

So I guess either they have no interest in contact or simply have not considered it as yet.
Maybe they have decided that contact would not be in their best interest? or they are waiting like us for some directed transmission... lol.. two players listening and no one talking. And the possibility's could go on and on and on.

I do not think we are alone in the Universe or our own Galaxy for that matter but for now we remain in isolation until such time we have some evidence that there are others close by.

This has been an interesting discussion thus far.

I do wounder that if there are much older civilizations in our Galaxy and say they did go through a TV like phase (they may well not have), then either the bubble of that transmission has either not reached us yet or it has passed us.. then again if it came from extreme distances the signal degradation would make it indecipherable from static I guess.

 

[Michael Allen]

That was my understanding of it as well, that this sort of detection took a directed transmission.

So I guess either they have no interest in contact or simply have not considered it as yet.
Maybe they have decided that contact would not be in their best interest? or they are waiting like us for some directed transmission... lol.. two players listening and no one talking. And the possibility's could go on and on and on.

I do not think we are alone in the Universe or our own Galaxy for that matter but for now we remain in isolation until such time we have some evidence that there are other close by.

This has been an interesting discussion thus far.

I do wounder that if there are much older civilizations in our Galaxy and say the did go through a TV like phase (they may well not have), then either the bubble of that transmission has either not reached us yet or it has passed us.. then again if it came from extreme distances the signal degradation would make it indecipherable from static I guess.

My favorite theory is that "they" are transmitting at a bit rate so huge that it sounds like noise to us and our electronics can't handle the decoding--i.e. the delay times on our own semiconductors may make any signal into garbage due to gaps.

Of course this gets dangerously close to confirmation bias and an increasingly unfalsifiable hypothesis on why we seem to have no signals from ET.

 

[stonehart]

My favorite theory is that "they" are transmitting at a bit rate so huge that it sounds like noise to us and our electronics can't handle the decoding--i.e. the delay times on our own semiconductors may make any signal into garbage due to gaps.

Of course this gets dangerously close to confirmation bias and an increasingly unfalsifiable hypothesis on why we seem to have no signals from ET.

Close to confirmation bias or not that is an elegant way of looking at the problem.

 

[Michael Allen]

Another interesting thought occurred to me:

We need to think about the scale of time when computing these probabilities. It may be there are many civilizations who have tried to direct a signal in our direction at certain times but we didn't have our ears on and vice versa. Would they turn on the signal for hours, days, weeks, years, decades or centuries? In the vastness of space and time the probability that we have our own devices attuned at the right time, the right frequency and the right direction might be vanishingly small. There are many variables to consider

Power of transmission
Direction of transmission
Frequency and bandwidth
Data rates (can our electronics handle their data rates?)
Length of time of transmission

It would be instructive to note how long SETI stays with it...my guess is that the probability of receiving a transmission in the next 200-500 years is near 1.0 if we continually scan the skies day and night for the entire duration. But SETI may be discontinued long before that almost guarantees we won't hear of anything, turn off the lights and conclude that no one's talking. Perhaps others have done the same.

Even more interesting is the crazy notion that the UFO phenomena itself is a form of transmission that is beyond our comprehension--i.e. that some civilization far away has found a way to remotely manipulate the very fabric of space and time to create forms and apparitions. Probably waiting for us to use our gravimetric holography machines to send a response!

 

[stonehart]

Another interesting thought occurred to me:

We need to think about the scale of time when computing these probabilities. It may be there are many civilizations who have tried to direct a signal in our direction at certain times but we didn't have our ears on and vice versa. Would they turn on the signal for hours, days, weeks, years, decades or centuries? In the vastness of space and time the probability that we have our own devices attuned at the right time, the right frequency and the right direction might be vanishingly small. There are many variables to consider

Power of transmission
Direction of transmission
Frequency and bandwidth
Data rates (can our electronics handle their data rates?)
Length of time of transmission

It would be instructive to note how long SETI stays with it...my guess is that the probability of receiving a transmission in the next 200-500 years is near 1.0 if we continually scan the skies day and night for the entire duration. But SETI may be discontinued long before that almost guarantees we won't hear of anything, turn off the lights and conclude that no one's talking. Perhaps others have done the same.

I really like that post and is an extremely valid comment on the whole situation and may just be the whole problem in a nutshell.
I do get the feeling that contact if and when it is made will happen because we stumble over each other and not because we have been looking for directed signals.

This last statement may not be well liked but is contact even desirable for either civilization? I am far from paranoid but I have no traffic with the "helpful space brothers" crowed that think all Aliens out there would be happy hippie space friends.

Frankly I feel even with the best of intentions if we were to come in contact many years from now with a less advanced civilization (given we work out how to travel long distances), we could cause harm or even worse out right exploit them and their world.

It is also a possibility that this could also happen to us.

Anyway that is getting off track.

 

[Michael Allen]

Well given the direction of this discussion, I think this is appropriate.

SETI Institute to shut down alien-seeking radio dishes - San Jose Mercury News

 

[stonehart]

Well given the direction of this discussion, I think this is appropriate.

SETI Institute to shut down alien-seeking radio dishes - San Jose Mercury News

Bit sad considering they only need 5 million to keep it running for now... how much is spent by the government on bombs and guns per day?

 

[Derik]

Bit sad considering they only need 5 million to keep it running for now... how much is spent by the government on bombs and guns per day?

How much is spent on welfare per day? How much is spent on ridiculous EPA regulations per day? How many businesses that could invest in SETI are run out of business because of incredibly expensive green initiatives per day? The DoD is actually a smaller fraction of the expenditures per day than you might think. Small business and individual investment are where SETI gets its reliable funding (and I was one of them), but current Obama policies are policies that have ended the freedom to contribute excess wealth to organizations like SETI. It is sad! But don't blame it all on DoD spending.

 

[Muadib]

How much is spent on welfare per day? How much is spent on ridiculous EPA regulations per day? How many businesses that could invest in SETI are run out of business because of incredibly expensive green initiatives per day? The DoD is actually a smaller fraction of the expenditures per day than you might think. Small business and individual investment are where SETI gets its reliable funding (and I was one of them), but current Obama policies are policies that have ended the freedom to contribute excess wealth to organizations like SETI. It is sad! But don't blame it all on DoD spending.

You must be joking, the defense budget for this year is $647 billion dollars, you're honestly going to sit there and pretend that "green initiatives" are costing business that much money? Total nonsense. We account for 41% of the world's total defense expenditures and it's only getting larger, look at this chart from 2011 for an example:

So we spend more than China, Russia, the UK, France and the next 10 countries combined together on defense. That's 14 countries total who when combined together don't spend as much as we do on defense. If you eliminated all welfare and green initiatives for the next year you still wouldn't come close to making the amount that we spend on defense for one year. I agree that it's not all the DOD's fault, but blaming it all on Obama is pure nonsense. I don't know where you're getting your facts but the fact is that the largest tax increases in history have all come from Republican presidents, not Obama. Do we really need to outspend the world by such a large margin to keep this country safe? I highly doubt it.

 

[Goggs Mackay]

Surely if escaping RF is from so far away, it is likely to be exceptionally weak in signal to noise, consequently, only the largest of arrays would have much of a chance. I am no astronomer but dont these arrays look more for strong signals from pulsars or big-bang events? I don't know the numbers but there are so few places equipped to do all this and so many frequencies to listen to, I actually don't find it surprising.

 

[Derik]

@Muadib, I didn't claim that dod spending wasn't high. It should be the highest government expenditure because that is the primary responsibility of the government. I have no problem giving my tax dollars for defense at all. One big problem is that the gov keeps investing in these projects that end up going under (e.g. solyndra) and they keep wanting to cut defense to fund those projects. Defense spending is one of the smaller slivers of the US spending pie (billions of around 7 trillion per year). I don't know how much the US spends on defense compared to other countries, nor am I too concerned about that, nor is it relevant. My point was simply that the US government's spending priorities are so screwed up, even private citizens have trouble spending on projects they used to love to spend money on, because our taxing, regulation fees, and other fees are way out of control.

 

[exo_doc]

From what I understand, SETI can only detect arbitrary radio transmissions (i.e. transmissions not necessarily directed at the earth intentionally) from about 0.3 LY distance

Wikipedia - "Fermi Paradox"

So even if there is a civilization in the local solar neighborhood going through what ours did in the last century with regard to technology, we would be unable to detect it unless they intentionally directed a narrowband signal toward us.

Well that just sucks.
And makes me wonder how other civilizations could hear us. I thought Earth was putting out as much radio energy as a star. By the time it travels to say, Sirius (@ 8 light years away) does that mean it would be too weak to even detect? Maybe Sirians couldn't piece together anything intelligent, but at least know that some sort of artificial radio was coming from here?

Besides, granting ever diminishing radio signal strength via "Fermi Paradox", ...then the universe could be awash in weak radio signals and we'd not be able to detect it. Would that not be so?

 

[Muadib]

@Muadib, I didn't claim that dod spending wasn't high. It should be the highest government expenditure because that is the primary responsibility of the government. I have no problem giving my tax dollars for defense at all. One big problem is that the gov keeps investing in these projects that end up going under (e.g. solyndra) and they keep wanting to cut defense to fund those projects. Defense spending is one of the smaller slivers of the US spending pie (billions of around 7 trillion per year). I don't know how much the US spends on defense compared to other countries, nor am I too concerned about that, nor is it relevant. My point was simply that the US government's spending priorities are so screwed up, even private citizens have trouble spending on projects they used to love to spend money on, because our taxing, regulation fees, and other fees are way out of control.

I'm sorry but your example is silly, Solyndra was loaned $575 million dollars, 70% of which was declared a total loss for taxpayers. How does that even come close to comparing to $674 billion dollars for defense, how do you justify that statement when you've said that $674 billion dollars is a small amount of our national spending, doesn't it follow that $575 million would be even less, so miniscule that it isn't even worth talking about, not even close to 1% of the defense budget for example? The amount that other countries pay is relevant since our defense spending is so out of proportion to what other countries pay and yet they are just as safe, if not safer than America. I agree that the governments spending priorities are screwed up, they defunded SETI a long time ago, they've talked about slashing NASA's budget which is especially ridiculous considering that about 1/2 of a cent of each tax dollar keeps NASA funded. If you really think that it costs $674 billion dollars to properly secure this country, I have a bridge in Brooklyn that you might be interested in. Also, blaming the current government for our economic woes is equally silly but we need not go there. The governments spending priorities are indeed screwed up, how about less for the military industrial complex and more return on our investment from actual worthwhile projects like space, schools and alternative energy development? Nah, that's just crazy, we need more guns and bombs! Then we can sit around and wonder why America is falling behind the rest of the free world in almost every category, but we'll be really, really safe while our nation crumbles around us!

 

[Michael Allen]

Well that just sucks.
And makes me wonder how other civilizations could hear us. I thought Earth was putting out as much radio energy as a star. By the time it travels to say, Sirius (@ 8 light years away) does that mean it would be too weak to even detect? Maybe Sirians couldn't piece together anything intelligent, but at least know that some sort of artificial radio was coming from here?

Besides, granting ever diminishing radio signal strength via "Fermi Paradox", ...then the universe could be awash in weak radio signals and we'd not be able to detect it. Would that not be so?

Well, I have seen that statement somewhere that the earth puts out the radio flux comparable to a small star, but this doesn't jive with the earlier quote on the problems of detecting non-directed signals further than 0.3 LY. Seems as though a radio flux comparable to a small star would be detected--perhaps it is and is dismissed as a star--not sure. I think its an important question:

What kind of equipment would be necessary to construct on some planet, rock or space probe near Sirius or Alpha Centauri to detect the artificial signals that are broadcast daily here on earth?

 

[Michael Allen]

Bit sad considering they only need 5 million to keep it running for now... how much is spent by the government on bombs and guns per day?

Which just goes to prove my point earlier--if we don't spend enough time listening, we probably wont detect anything--and if we don't detect anything we're probably not even going to bother to transmit.

LOL--laughable in the extreme was our attempt to broadcast

The Arecibo message was broadcast into space a single time via frequency modulated radio waves at a ceremony to mark the remodeling of the Arecibo radio telescope on 16 November 1974.[1] It was aimed at the globular star cluster M13 some 25,000 light years away because M13 was a large and close collection of stars that was available in the sky at the time and place of the ceremony.[2] The message consisted of 1679 binary digits, approximately 210 bytes, transmitted at a frequency of 2380 MHz and modulated by shifting the frequency by 10 Hz, with a power of 1000 kW. The "ones" and "zeros" were transmitted by frequency shifting at the rate of 10 bits per second. The total broadcast was less than three minutes.[1][3]

Really...3 freaking minutes! Seriously what is the probability that someone some where is going to pick up that signal and then say "well it was weird...but we can't reproduce it!--so into file 13!"

So perhaps the other's are doing the same exact thing...send a 3 minute broadcast out somewhere, we almost certainly are guaranteed to miss it! Here's a nice calculation, how many Arecibo type broadcasts (assume about 1500 within 100 LY) have been missed by our own listening? Remember the variables, direction, length of transmission, strength, bit rate, bandwith/frequency, etc....

OK so the Arecibo message wasn't a "real attempt to contact ET, just a demonstration" But I wonder what the duration of the other messages were

Like this one: A Message From Earth - Wikipedia, the free encyclopedia

"... for the transmission which took four and a half hours."

OK, if we're looking for a signal we better not miss at least a 4.5 hour window! I would only hope that ET our not as naive as we are.

Think about it this way, lets say one civilization decided to transmit a signal once in 50 years with a 4.5 hour window -- what is the probability (given all the choices) we'd even pick it up?

The point I am making is that if we really want to commit to sending a signal, we should turn it on like a beacon and never turn it off. 3 minutes, 3 hours or even 3 days is just not long enough to overcome the vanishing probability that our target is even actively listening.

 

[stonehart]

How much is spent on welfare per day? How much is spent on ridiculous EPA regulations per day? How many businesses that could invest in SETI are run out of business because of incredibly expensive green initiatives per day? The DoD is actually a smaller fraction of the expenditures per day than you might think. Small business and individual investment are where SETI gets its reliable funding (and I was one of them), but current Obama policies are policies that have ended the freedom to contribute excess wealth to organizations like SETI. It is sad! But don't blame it all on DoD spending.

Muadib answered this more than well enough.. but it did remind me I had this pick in my folder some place.

 

[Stagger Lee]

Was it Steven Hawking who warned us about sending signals into the great unknown?
I tend to agree, giving up our location to an agressive species may not be in our best interest.

 

[PCarr]

So.....are the radio signals there? We are just not listening on the right frequencies?

That is definitely possible. There is a large literature on that. Google, for example, Benford beacons.