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Thread: Galactic net

  1. #1
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    Galactic net

    Reflected signals return to earth after 50 or more years, but the signals are about a billion times too weak for us to receve them. A billion times improvement in the technology, seems very improbable, ever, as the miscellanious noise is much stronger than the bounced signal.
    Somewhat different is however workable with today's technology. We transmit our math, science and language lessons to ET who lives several light years away. ET receives and records the information; then transmits it in approximately the opposite dirrection to another ET who also records and sends in about the opposite direction. Occasionally an ET transmits an old recording in some direction because ET's scientists have determined some of the information is valuable to somebody, so the Information could return to Earth 50 years or even 50,000 years after it was sent with only minor errors. I call this communications system the Galactic Net. As far as I know, I am the inventor, but possibly the galactic net has been operating for millions of years, preserving the wisdom of long dead civilizations. Neil

  2. #2
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    Perhaps a little less ambitiously, I usually call this concept the Interstellar Internet
    http://www.bautforum.com/showthread....09#post1711609
    ...after all, we could never be sure that the 'net covers the whole galaxy, as parts of it would be separated by 100,000 years of signal latency...

    I don't claim to be the originator of this term, as it is used quite widely elsewhere. The idea of a galactic data-sharing network is one of the more optimistic solutions to the Fermi Paradox, although if it exists we should be prepared to treat all the information we might receive with the same skepticism that we treat information gained from the Earth-bound internet.

  3. #3
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    Here's a proposal for a galactic internet on a grand scale;
    The Cepheid Galactic Internet

    We propose that a sufficiently advanced civilization may employ Cepheid variable stars as beacons to transmit all-call information throughout the galaxy and beyond.

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    Dream on Mssrs John G Learned, R.P Kudritzki, S. Pakvasa and A. Zee !!

    Dream on !

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    The Cepheid internet certainly seems to be a case of overkill. Interstellar communication should be considerably easier than sending spacecraft from star to star, although there are arguments to be made for both approaches. We can already send signals that would be detectable at interstellar distances, given existing equipment; if very large arrays of recievers can be built, on Earth or (preferably) in space, we could receive remarkably weak signals.

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    Quote Originally Posted by eburacum45 View Post
    The Cepheid internet certainly seems to be a case of overkill. Interstellar communication should be considerably easier than sending spacecraft from star to star, although there are arguments to be made for both approaches. We can already send signals that would be detectable at interstellar distances, given existing equipment; if very large arrays of recievers can be built, on Earth or (preferably) in space, we could receive remarkably weak signals.
    The 'Cepheid internet' is pure fantasy ...
    Quote Originally Posted by Learned etal
    We have not modeled Cepheids in order to determine the optimum neutrino energy, {for Cepheid modulation purposes} but it is irrelevant for the present disucssion: we leave it as an engineering problem for the star tickling civilizations out there.
    Oh brother ! Give me a break !

    Whilst we can transmit significant signals from very large and powerful transmitters located on permanent Earth based facilities, the same signals are not able to be generated by moving spacecraft. Its simply not feasible to manage the precision of the signal beamwidth and power distribution across the boresight, needed for precise propagation, whilst achieving the minimum antenna gain to cover such distances, (let alone generating the raw power). There's also a limit to the transmission rate ... and its a function of power levels, antenna and amplifier gain, harmonic distortion, thermal noise, intervening media permittivity, error rates etc, etc ...

    Reception of distant 'weak' astronomical object generated signals, is feasible using Earth-based large phased arrays and very low noise amplifier technologies, but the magnitudes of the signal sources in these cases, are still in the order of astronomical (or stellar) sized magnitudes.

    There is no way a human constructed spacecraft, could come anywhere near generating the signal levels required to transmit meaningful data streams over light-year distances, such that they could be received by current receiver array technologies.

    Regards

  7. #7
    Would you clarify what is the difference between "managing the precision of the signal beamwidth and power distribution across the boresight, needed for precise propagation, whilst achieving the minimum antenna gain to cover such distances" from a moving spacraft compared with doing the same thing from a moving planet. I must be missing something simple and fundamental.

    Would you confirm, as you imply, that alien constructed spacecraft may be able to generate signal levels necessary for interstellar signalling.

    And further would you confirm that you agree that more effective arrays would be able to detect weaker signals.

    Put another way, some of your objections appear to be based upon an assessment of current technology. Isn't that often a risky basis for predictions of what is possible?

  8. #8
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    I believe there was a study (probably on arXiv) that demonstrated that it may be more effective (greater bandwidth) to send data physically as opposed to using a signal channel, be it electromagnetic or neutrino: sort of an interstellar sneakernet, also expressed as "never underestimate the bandwidth of a 747 full of floppy disks," which should probably be updated to "...sd cards."
    Information about American English usage here and here. Floating point issues? Please read this before posting.

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    That is the 'Bracewell Probe' concept;
    http://en.wikipedia.org/wiki/Bracewell_probe
    The amount of information carried by such a probe could be very large, but the power required to accelerate such a probe to interstellar speeds and to decelerate it on arrival would make it not worth doing for shorter messages, when compared with building large transmitters and even larger receivers at each end.

    Here's a page about the problem as considered by the Project Icarus people ; as one can see, there are no clear answers yet, but no real showstoppers either.
    http://news.discovery.com/space/proj...ns-120206.html
    The Daedalus team's calculations showed that with such a system we could expect to receive over 800 kilobits per second (kbps). That means that Daedalus could transmit a 1 megabyte (MB) file to Earth in about 10 seconds. That would be a disappointing broadband connection, but for interstellar distances it is quite impressive.
    It's not impossible to send messages from star to star- just very, very tricky.

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    Quote Originally Posted by Eclogite View Post
    Would you clarify what is the difference between "managing the precision of the signal beamwidth and power distribution across the boresight, needed for precise propagation, whilst achieving the minimum antenna gain to cover such distances" from a moving spacraft compared with doing the same thing from a moving planet. I must be missing something simple and fundamental.
    Please see eburacum's 'Icarus project' post. It covers mostly what I hastily threw together in my previous post.
    For what its worth, I don't agree with their final assessment that interstellar travel is feasible, however. (My opinion only).

    Quote Originally Posted by Eclogite
    Would you confirm, as you imply, that alien constructed spacecraft may be able to generate signal levels necessary for interstellar signalling.
    Certainly not !
    I haven't the foggiest idea of what an alien is for starters do you ?
    I was alluding to human capabilities.

    Quote Originally Posted by Eclogite
    And further would you confirm that you agree that more effective arrays would be able to detect weaker signals.
    Sure and there are constraints on just how large that array can get, when compared with the returns achievable by doing so.

    Quote Originally Posted by Eclogite
    Put another way, some of your objections appear to be based upon an assessment of current technology. Isn't that often a risky basis for predictions of what is possible?
    I wasn't predicting what was possible. I was stating what is feasible. We live in the real world.
    Technology is not the only limiting factor.
    Complexity and economics constrain the world of engineering .. as much as the Physics involved in propagating signals over such distances.

    Regards

  11. #11
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    Quote Originally Posted by swampyankee View Post
    I believe there was a study (probably on arXiv) that demonstrated that it may be more effective (greater bandwidth) to send data physically as opposed to using a signal channel, be it electromagnetic or neutrino: sort of an interstellar sneakernet, also expressed as "never underestimate the bandwidth of a 747 full of floppy disks," which should probably be updated to "...sd cards."
    A bit of word-spin here. A 'signal channel' is information theory speak for a message propagation path.

    The same abstraction could thus also be applied to the concept of passing floppy disks over interstellar distances (or 'sneakernet', 'neutrino comms', etc).

    Regards

  12. #12
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    Quote Originally Posted by neilzero View Post
    Reflected signals return to earth after 50 or more years, but the signals are about a billion times too weak for us to receve them. A billion times improvement in the technology, seems very improbable, ever, as the miscellanious noise is much stronger than the bounced signal.
    Somewhat different is however workable with today's technology. We transmit our math, science and language lessons to ET who lives several light years away. ET receives and records the information; then transmits it in approximately the opposite dirrection to another ET who also records and sends in about the opposite direction. Occasionally an ET transmits an old recording in some direction because ET's scientists have determined some of the information is valuable to somebody, so the Information could return to Earth 50 years or even 50,000 years after it was sent with only minor errors. I call this communications system the Galactic Net. As far as I know, I am the inventor, but possibly the galactic net has been operating for millions of years, preserving the wisdom of long dead civilizations. Neil
    So each node is a repeater site where the signal is again amplified? This is an example where cooperation has its advantages.

    Besides the physical issues, there would also have to be communication protocols (analogous to TCP/IP), modulation techniques, decoding, and some common language etc. How would different life-forms establish some kind of communication? I can imagine there being several back and forth messaging until there is a full communication connection on all protocol levels. Depending on the distance it could take centuries just to establish a connection. Interesting problem.

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    I had an idea for a fictional universe where micro-wormholes, only big and stable enough to send a laser beam in a hard vacuum, are used to connect solar systems. They are massively expensive, so only one or two per solar system at most. Light speed, like radio, laser, what have you, handles the rest. This long latency, however, means internet style communications, like e-mail and forums, are more common than Star Trek video phone.
    Since the local FTL 'breaks' wormholes, a colony can spend hundreds, and occasionally thousands, of years before it is 'connected'.
    Unmanned packet ships, basically hard drives with FTL drives, are the only other commercial means of FTL communications in the setting, but that's a different story.

  14. #14
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    Quote Originally Posted by Selfsim View Post
    A bit of word-spin here. A 'signal channel' is information theory speak for a message propagation path.

    The same abstraction could thus also be applied to the concept of passing floppy disks over interstellar distances (or 'sneakernet', 'neutrino comms', etc).

    Regards
    I'm not an information theorist; I'm an aerospace engineer turned software developer and physics teacher.
    Information about American English usage here and here. Floating point issues? Please read this before posting.

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    Quote Originally Posted by eburacum45 View Post
    That is the 'Bracewell Probe' concept;
    http://en.wikipedia.org/wiki/Bracewell_probe
    The amount of information carried by such a probe could be very large, but the power required to accelerate such a probe to interstellar speeds and to decelerate it on arrival would make it not worth doing for shorter messages, when compared with building large transmitters and even larger receivers at each end.

    Here's a page about the problem as considered by the Project Icarus people ; as one can see, there are no clear answers yet, but no real showstoppers either.
    http://news.discovery.com/space/proj...ns-120206.html
    ...
    It's not impossible to send messages from star to star- just very, very tricky.
    Thanks for those links eburacum they very much help to fast-track this conversation. Both links cover the basics of what I'm on about, although I disagree with the Icarus team conclusion that the goal of interstellar travel, and remote probe communications over light yrs, is practically feasible.

    I notice the Icarus project scope initially targetted a flyby of Barnard's Star (6 lyrs). They say they revised this to address other 'more appropriate' targets. I think the most likely habitable Class M Mesoplanets are all either ~1,000 lyrs (or upwards) distant. Gliese 581d is ~20.2 lyrs. There are some warm Superterrans at ~35 lyrs, so I hope these targets are now within their project scope. It makes no difference anyway, I suppose, because they still don't have a practically feasible solution or design.

    In their own words about project risk assessment:

    Another major risk to the success of the project is the inability of the design team to find a solution to a design issue. This may be due to an emerging contradiction from the ToR or just due to the difficulty of producing an engineering or physics solution. In the event that this occurs, the best approach would be to make credible assumptions about that anomalous component/function and to continue with the remaining design, leaving this problem area unresolved.
    So, if they are making interim assumptions in order to proceed, how can they conclude that the undertaking is practically feasible ?

    The show-stoppers are in the details .. and their assumptions could easily erase visibility of any numbers of them. This is quite a flawed method of proceeding, if you ask me, (ie: ostrich-head-in-the-sand approach).

    Regards

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    well Claudio Maccone thinks interstella networks might be possible with gravitational lens
    the link is to a talk he gave at the seti institute
    http://www.youtube.com/watch?v=ObvKVe5H8pc&feature=plcp

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    Quote Originally Posted by mutleyeng View Post
    well Claudio Maccone thinks interstella networks might be possible with gravitational lens
    the link is to a talk he gave at the seti institute
    http://www.youtube.com/watch?v=ObvKVe5H8pc&feature=plcp
    Ok .. this is about developing a remote probe for performing deep space observations making use of the Sun as a gravitational lens .. for various targets.

    As I have presented ad nauseum, such observations of remote exo-planetary atmospheres lead to nothing more than more inference based conclusions as far as exo-life is concerned. Earth-like life biological tests still have to be performed locally at the exo-site (on a direct sample), and the results would then have to retransmitted back to Earth. So, the closest targets of interest are ~20 to 35 lyrs distant, right ?

    How can a probe travel that distance, without dying due to electronics death, power death, losing its alignment, fuel leakage, losing antenna alignment with the Sun's limb etc, etc ..? How could such task complexity be managed ? All the same goes for even the telescope sitting at or beyond the grav. lens focal point !

    Engineered systems (including: materials science, electronics, etc) are still constrained by physical lifetime tolerances. Nothing designed so far by humans has 'lived' for the duration of the flights we're talking about here, let alone remaining operationally stable !

    As far as using this being used as communications network infrastructure ...??... Baloney !

    Its all pure practical fantasy ... and not a very good one, either !

    Gimme (another) break !

    Also, at around the 55:54 min mark Maccone says:
    Quote Originally Posted by Maccone
    So, this is the political "trick", (sorry), if you like, to be tried in order to have the support of a larger community than just the SETI side...
    What sort of scientist is this guy ? Advocating a political "trick" as some kind of attempt at deceiving the funding community to give him what he and SETI want, because of his beliefs ?
    I'm sorry .. but this guy should get everything he has coming to him for advocating such deliberate deception !
    What arrogance ! Does he think funding authorities can't see through his "trick" ??

    This presentation constitutes further independently verifiable evidence that the remote detection methods proposed ostensibly as a means of furthering the 'hunt' for exo-life, (if that's the application such lensing probes are being suggested for), is nothing more than a sham and a total waste of resources !

    What utter nonsense !

  18. #18
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    your not going to buy his book then?

  19. #19
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    Quote Originally Posted by mutleyeng View Post
    your not going to buy his book then?

    Not at all !
    I would still consider it.

    Let me see, it would take prime place right next to my Erich von Daniken collection, I think.



    Cheers

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