Thanks guys.

Ok, thanks.
I should have said "maybe we are alone in our galaxy".

What are spikes and triplets? It's been many years ago since I was familiar with those terms?

This may be helpful.
http://setiathome.berkeley.edu/sah_glossary.php

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What are spikes and triplets?

If you didn't already, read these:
http://seticlassic.ssl.berkeley.edu/about_seti/about_seti_at_home_1.html
http://seticlassic.ssl.berkeley.edu/screensaver/index.html

http://setiathome.berkeley.edu/sah_glossary.php

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- ALF - "Find out what you don't do well ..... then don't do it!" :)
 

Ok, thanks.
I should have said "maybe we are alone in our galaxy".

What are spikes and triplets? It's been many years ago since I was familiar with those terms?

Well, yes, we've been doing MB, or some version of a narrowband search since the beginning of S@H, and no, we haven't found anything yet...that we know of. As far as I know, we've only scratched the surface of the results that us crunchers have been submitting at a furious rate for many years. That's where the "NTPCkr" (Near-Time Persistency Checker, we pronounce the abbreviated form as "nit-picker," which is a really fitting name) comes into play. Eventually, we'll get it fired up and running and it will start making a list of what it has found. And it's going to "nit-pick" about everything, such as.. if 20,000 spikes were found from the same direction, it will be assumed that maybe it is just a pulsar, but when a triplet is found from the same location... as I said in my earlier explanation.. "we're looking for something that doesn't look like everything else." A triplet doesn't look like all the spikes, so that is flagged as "interesting" and we'll come back to it later, such as.. making requests at Arecibo to look at that spot again, or go to some other radio telescope (or even an array of them) and get some more recordings.

So.. we just don't know yet if we've found anything. But don't give up hope.. we'll know/find out eventually.


As far as how many possible candidates there are.. the Drake Equation is a reasonable starting point. Of course, it isn't conclusive or highly-accurate, and depending on how much you bias/shift your range of values for all the variables, you can get hugely-varying results.

There's a couple of theories and speculations.. if we assume the "rare-Earth hypothesis" (which means we're a cosmological mistake, basically), the Drake Equation says there is 1 or less civilizations per galaxy.

Taking the lower end of the variable ranges suggests there may be as little as 1000 civilizations in this galaxy. Going on the upper end of the variable ranges reaches as high as 280,000,000. Though it seems that the most-accepted value is somewhere right around 36,000,000.

So here's some napkin-math that I've just done. Our galaxy is about 100,000 lightyears across, and if you only consider two dimensions, it covers an area of about 7.8 billion square lightyears. If we go with the lower end of the range where there are 1000 civilizations, that gives each one a radius (if everyone is evenly-spaced) of ~450 lightyears.

The 36 million figure gives us about 2.5 lightyears for a radius, which would suggest.. that there is an intelligent civilization around a planet at Alpha Centauri.



So.. it's hard telling what is out there, exactly. As Hal said before.. "if we don't look, we won't know." Personally.. I think the statistics..even if it is a 1-in-many-billions shot.. there's zero chance that we're the only intelligent life in the universe. I do believe that we may never find out for sure..but if each galaxy has a few hundred billion stars, and there's a few hundred billion galaxies.. there's no way we're the only ones.

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Thanks Hal,
If they turn out to be little green men, I'm gonna croak.

Joe, what I was responding to was Hal's possible meaning that it was preferable to remain within our sparsely populated part of the galaxy and thereby not needing the long distance power of AP (the short term pulses that you are talking about). I was using MB narrowband meaning narrow in frequency not shorter/narrower in duration. Unless I am getting things all jumbled up which could be the case.

If we take the width of Hal's image as 100000 light years, the outer circle surrounding our position appears to have a diameter just slightly less than 5000 light years by my rough measurements on the displayed image. Expecting our searches to detect anything near that 2500 light year radius requires that the transmitter be more powerful than a civilization at our stage of development could support. Assuming e.t. has the same kind of budgetary constraints we do, but nevertheless has good reason to send out signals with maximum reach, pulses seem more likely to me if they can serve whatever reason the system was built.

The question of motivation of course will remain unanswered until (and probably after) we actually detect some signal which is clearly sent by a technical civilization.

                                                                  Joe

I think the main point I was trying to make was that out of the 300 billion or so starts in our galaxy only a fraction of them are likely to have life. I have not heard any number quoted, but if the galactic habitual zone is true then is looks like probably less than 1/3 of the stars.
Last I heard they were thinking there are about 3 billion potential habitual planets.

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OK, that makes it clearer for me. I didn't realize that that sparsely populated area was itself so huge. In any event I keep coming down on the side of AP. We have been working many years with MB without any success. I don't mean give it up. It could work. Let the people who believe in it crunch themselves to death and I sincerely wish them the best and hope they find it. Me personally I just get off on the idea of AP.

Joe, what I was responding to was Hal's possible meaning that it was preferable to remain within our sparsely populated part of the galaxy and thereby not needing the long distance power of AP (the short term pulses that you are talking about). I was using MB narrowband meaning narrow in frequency not shorter/narrower in duration. Unless I am getting things all jumbled up which could be the case.

If we take the width of Hal's image as 100000 light years, the outer circle surrounding our position appears to have a diameter just slightly less than 5000 light years by my rough measurements on the displayed image. Expecting our searches to detect anything near that 2500 light year radius requires that the transmitter be more powerful than a civilization at our stage of development could support. Assuming e.t. has the same kind of budgetary constraints we do, but nevertheless has good reason to send out signals with maximum reach, pulses seem more likely to me if they can serve whatever reason the system was built.

The question of motivation of course will remain unanswered until (and probably after) we actually detect some signal which is clearly sent by a technical civilization.

                                                                  Joe

And Harvard is doing Optical Seti. looking for laser signals. To bad we couldnt crunch them.

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Old James

Assuming e.t. has the same kind of budgetary constraints we do, but nevertheless has good reason to send out signals with maximum reach, pulses seem more likely to me if they can serve whatever reason the system was built.

The question of motivation of course will remain unanswered until (and probably after) we actually detect some signal which is clearly sent by a technical civilization.

IMO if we find something it will be a supurious signal which is why I do as many APs as possible

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Joe, what I was responding to was Hal's possible meaning that it was preferable to remain within our sparsely populated part of the galaxy and thereby not needing the long distance power of AP (the short term pulses that you are talking about). I was using MB narrowband meaning narrow in frequency not shorter/narrower in duration. Unless I am getting things all jumbled up which could be the case.

If we take the width of Hal's image as 100000 light years, the outer circle surrounding our position appears to have a diameter just slightly less than 5000 light years by my rough measurements on the displayed image. Expecting our searches to detect anything near that 2500 light year radius requires that the transmitter be more powerful than a civilization at our stage of development could support. Assuming e.t. has the same kind of budgetary constraints we do, but nevertheless has good reason to send out signals with maximum reach, pulses seem more likely to me if they can serve whatever reason the system was built.

The question of motivation of course will remain unanswered until (and probably after) we actually detect some signal which is clearly sent by a technical civilization.

                                                                  Joe

Joe, what I was responding to was Hal's possible meaning that it was preferable to remain within our sparsely populated part of the galaxy and thereby not needing the long distance power of AP (the short term pulses that you are talking about). I was using MB narrowband meaning narrow in frequency not shorter/narrower in duration. Unless I am getting things all jumbled up which could be the case.

Hal,

One way I can interpret what you said is that it makes more sense to continue on with MB narrowband.

The AP vs MB aspect of your question has been neglected. The advantage of narrow pulses is that each pulse can be very powerful without requiring a continuous supply of high power. A one millisecond pulse sent once a minute would be 60000 times as strong as a continuous transmission for the same average power. That makes the signal reach over 15 times further.

                                                                   Joe

our solar system marked in an area between two of these areas.

That does look like we're far out in the uncharted backwaters of the unfashionable end of the western spiral arm of the galaxy.

I like to think of it as between Tornado & Hurricane Alley.

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Hal,

One way I can interpret what you said is that it makes more sense to continue on with MB narrowband.

our solar system marked in an area between two of these areas.

That does look like we're far out in the uncharted backwaters of the unfashionable end of the western spiral arm of the galaxy.

I think we live in the Persus spur?

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[/quote]

Old James

our solar system marked in an area between two of these areas.

That does look like we're far out in the uncharted backwaters of the unfashionable end of the western spiral arm of the galaxy.

Joe,
But 1% would still be nearly 3 billion suns. To me that is an awfully large sample of stars. If it's not in there we may be alone.

--edit--
Thanks again for the reference. I gotta hang on 'til 2020! :-)

There is an theory of a galactic habitable zone. Where stars are less dense in the galaxy and not blurting out radiation that would be harmful to life. Making the number of stars much smaller that may contain planets with life.
With that theory they created a map of the Milky Way galaxy. http://www.hal6000.com/seti/images/yah.png With the red areas denoting potentially to high of levels of radiation for life to be present & our solar system marked in an area between two of these areas.

Another theory is that those stars could have planets with life if the planet were to have a much stronger magnetic field. However that might make it harder to detect intelligent signals from such planets.

If we don't look we won't know.

I watched an episode on How the universe works about that same thing It seems you dont want to live in arm of the galaxy but between tham. Where we are.
Also thats why the lab slpits old tapes to send back to us. As detection im proves letrs have a look at an old tape and see if we get anything. Plus as a bounus it keeps us in work when Aricbo is down.

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Old James

Amen Hal.

Joe,
But 1% would still be nearly 3 billion suns. To me that is an awfully large sample of stars. If it's not in there we may be alone.

--edit--
Thanks again for the reference. I gotta hang on 'til 2020! :-)

There is an theory of a galactic habitable zone. Where stars are less dense in the galaxy and not blurting out radiation that would be harmful to life. Making the number of stars much smaller that may contain planets with life.
With that theory they created a map of the Milky Way galaxy. http://www.hal6000.com/seti/images/yah.png With the red areas denoting potentially to high of levels of radiation for life to be present & our solar system marked in an area between two of these areas.

Another theory is that those stars could have planets with life if the planet were to have a much stronger magnetic field. However that might make it harder to detect intelligent signals from such planets.

If we don't look we won't know.

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