Its a discussion thread, if it is 'spoiled' by there being more than one side to the discussion then all of/. is utterly pointless, just go talk to yourself! lol.
As for who says, energy says. It would take a monster amount of energy (read above) to travel to another star system. Surely such vast quantities of energy are far beyond what any individual would ever need. Thus it seems unlikely to me that one or a few people would ever possess by themselves the means and authority to deploy such large resources to such a project. If an entire civilization (or a large part of it) is both so impractical and so empowered that it would do such a thing then isn't it vastly more likely such a civilization would simply do something stupid and wipe itself out due to its own impracticality? That's the whole nut of the "scale beyond a few individuals" because if the whole society is insane then yes indeed they might dream of interstellar travel, but they're not going to be in a position to achieve it.
But again, what rational species would finance such a trip? The return on investment couldn't possibly make it worthwhile. A race which was so impractical in its outlook that it would expend vast resources with no return is unlikely to survive and prosper to the level of building starships, is it not?
Beyond that I think the 'slow road' is not such an easy thing. Even 0.1C is a HUGE amount of energy, as I calculated above, but going slower creates other obvious problems. To create a 'mechanism' (in the most general sense of the word) which would remain functional over 100's, 1000's, or 10's of thousands of years is far more difficult to imagine than sci-fi authors seem to think. Entropy is the enemy of everything, and the more complicated you have to make your mechanism in order to supply it with means to deal with more and more situations (remember, more and more unlikely problems will become significant factors over long stretches of time) the more failure prone it becomes. Biological systems rarely remain intact for time periods beyond a few decades for instance. Imagine a mechanism which had to withstand the high radiation environment of a 0.1C trip to the nearest star system for 50+ years. Is this possible? Would the requirements for additional mass to enable acceptable reliability simply bloat the mission far beyond feasible limits? Can something so complex function at 100% duty cycle without spares or maintenance for 50 years, even with advanced technology? At best we're looking at an extraordinarily difficult engineering problem, one many orders of magnitude beyond what we are familiar with.
As I've said before though, interstellar travel doesn't have to be literally impossible. It just needs to be infeasible enough that an advanced civilization has better things to do with its resources than fling them into space to never see again. Even if it does happen once in a long while we'd be VERY unlikely to meet aliens unless such things were fairly commonplace, given the vast size of the Universe.
Yes, somewhere else which is made of TADA! More hydrogen and helium! The problem is that on even a modest scale the Universe is remarkably homogenous. Once you posit a high level of technology its hard to imagine a very good reason WHY you would want to spend the huge cost to travel to the stars. If one says "well just because" then you have to posit a VERY irrational intellect, and it is hard to imagine such an intellect being able to carry out a mission to the stars.
Sure, we can imagine making 3 kilos of antimatter. What we can't imagine is what would be worth paying the humongous cost for it. Even in a future where energy is plentiful an amount equal to the current total power output of the human race would be enough to do a LOT with (look at what we today can do with it and then imagine that power applied through a much more advanced technology).
Again though, we can imagine ANYTHING, but where are there any signs of 'direct conversion' in our understanding of nature? I mean certainly we understand things in only a partial way, but there are no signs of any phenomenon under which matter is converted to energy. When people cry that we have all sorts of examples of technology 'nobody would have predicted before' I have to be pretty skeptical. People predicted and experimented with powered heavier-than-air flight for millenia for instance, and even achieved some limited success, certainly they had some idea of how to achieve it. Likewise with other technologies such as steam power, electricity, etc. Certainly Volta wouldn't have predicted micro-electronics and wouldn't be able to explain them with the physics he had at his disposal, but if you gave him a computer he'd probably correctly assert that it was an electrically based device, and people certainly did predict computers etc long before they became available. We have not even a wiff of a hint about things like 'direct conversion' today. If such a thing is possible it is FAR beyond us. Again, we could simply imagine such things from whole cloth, but that's just magical thinking, it doesn't really belong in a discussion of what is actually feasible and likely.
Yeah, I think the various AC's that have responded already have summarized things nicely, to reiterate:
1) FTL is LOGICALLY impossible. This is off the table. We may not fully understand the way the universe works but we have logically demonstrated that either there is FTL and no causality and no common universal laws of physics which apply within every reference frame equally (IE the laws of physics would change whenever you accellerated) or FTL is impossible. No appeal to "we don't know enough, we're ignorant" can get around this, Einstein did not leave ANY 'get out of jail free card' ways to get around it. No, not wormholes, they'd break down causality too, nor the 'Alcubierre Drive' which ALSO breaks down causality, etc. You can try to assume there are some sort of parallel worlds or something you can access via some handwavium tech, but frankly why not just posit that the right ritual enacted at the right phase of the Moon will open a door into Elfland? Nobody can EVER 'prove' such things don't exist, but you care to bet?
2) As for the "well, things always seem difficult until we do them", I would just like to point out what the 2nd AC said "...if it's at all possible, represents an intellectual and operational barrier an order of magnitude higher than anything mankind has encountered so far." except said AC is wrong in one sense. It isn't AN order of magnitude harder. All the list of things that were listed by JWSmythe above are maybe an order of magnitude, at most, harder than things that were done before them. Going from being able to travel to Mars to being able to travel to Alpha Centauri in something even roughly like the same time frame (IE less than a decades long journey) with a human crew is 12 orders of magnitude harder. Not ONE but TWELVE.
That's the thing people regularly fail to understand. They've been brought up on a steady diet of space opera/Star Trek where starships woosh around through space like its nothing and a trip to the next star system is like a jaunt to the next highway exit. THAT is surely fantasy. Even if some sort of FTL, or something nearly as good, proved to exist it would perforce have to be incredibly difficult to achieve, else natural phenomena would already exist which recapitulated the necessary phenomena for us to observe. The energies required must be beyond even what is achieved in the presence of billion solar mass black holes and such. No hint of such things is evident.
Perhaps our Universe was created by a prankster. It certainly seems like the limitations we face are such that the promise of surmounting them must always seem barely out of reach, but I think the prankster did a good job.
The point is, if you have the technology to do interstellar travel then you have the technology to make a 'pelt' or some 'gold' or whatever out of any matter you can get hold of, and it would be FAR FAR cheaper than transporting it across interstellar space. The economics can never make sense.
The colonization of North America is just not analogous. Suppose it took 40 years to sail from London to Manhatten and the cost of a single ship was as much as the entire GDP of Europe in 1700. There's no bloody chance at all that such a colonization would have ever taken place. Nor would a few troublemakers like the Pilgrims have had the wherewithall to hire such a ship to haul them across. Nor is it at all likely they would have survived when they got there without the eventual arrival of additional ships, etc.
I'm not 100% sure we can ever economically justify colonizing the Moon, though it seems likely, but some other Solar System which is a TRILLION TIMES further than Mars, a place we can barely imagine being at the very outermost edge of our current capabilities (and another place I can't really see ever being economical to colonize, though scientific exploration seems quite likely). A trillion times harder than just about too hard is beyond too hard, it is beyond even "what the hell, we'll learn something" hard. There's just no imagining with a practical imagination anyone finding a 'pelt' or a 'mineral' so unique and valuable that it would be worth many times over the total current power output of the human race to send it back.
Agreed. The question is who would take the leap across the great gulf when there are always much cheaper ways of getting more matter, even if you hve to take it from someone else? At best all the sponsors of such a mission can hope to get back is information, but as the author of the blog piece says, eventually there just isn't that much more to know that's really all that valuable that its worth going all that way at all that expense to get.
In terms of "why haven't we met anyone" (the Fermi Paradox) though we really don't need to assume that interstellar travel is NEVER undertaken, only that it is modestly rare. If intelligent life itself is fairly uncommon (probably not an unreasonable assumption, certainly plausible) then we could easily see ourselves being the only active intelligent species in the galaxy at this time.
It may be that simple curiousity and a drive to spread exists in some species to a degree which does drive them across the galaxy. Unlike many I'm not as sanguine about the ease of such a species becoming ubiquitous. Travel itself may be slower and more difficult than we imagine with a high cost and high rate of failure. Coupled with a moderately short survival time for technological civilizations might mean that each colony/Von Neuman probe on average produces less than one or only right about one offspring. It could then take vastly longer than the half-life of a species to explore a large part of the galaxy. In that scenario it may be that there are regions which are explored and 'occupied' in some sense for a time, but much/most of the galaxy remains virgin.
Even if these interstellar civilizations were moderately common the gulf of TIME is very large. If each lasts only a small handful of millions of years then most of time is empty of them. I really doubt that the artifacts of such a civilization would remain in any easily discoverable form for more than a few million years at most.
Thus in effect its easy to postulate we could be pretty much completely alone even without assuming the absolute infeasibility of interstellar travel. It just needs to be difficult and expensive. From where I stand it seems like that's exactly what it is! Even some advanced machine race which can make highly durable 'bodies' and has reached Kardeshev level 2 might not be able to spread all through the galaxy, or last very long.
No, actually they don't. Not on any scale larger than that which can be undertaken by a few individuals. Beyond that our activities, on a 'society scale' are quite practical. The exceptions are quite informative. The ancient Egyptians employed 1000s of people to build giant pyramids, for less than one century before their society collapsed. When it recovered they built much smaller underground tombs for the next 2000 or so years, never again building a large pyramid. Other 'whimsical' projects were on much smaller scales. In fact no building exceeded the size of the Great Pyramid of Cheops until the 20th Century (the Eiffel Tower was the first to equal it in height). Considering the crude technology at hand we could safely hypothesize that the Great Pyramid is pretty much unique in history. Certainly interstellar travel would necessarily entail a vast and prolonged effort by an entire society on a huge scale. History isn't especially sanguine about the likelihood of that happening.
Yes, in other words, "Its impossible, but let me imagine if it wasn't". Were such 'shifts' possible the laws of nature as we know them would be utterly overthrown. Again, I know, its not a popular opinion and you can always wave your hands and imagine some other imagining, but we can only extrapolate from what we know, not what we wish.
Yes, yes, well what are you doing? At best the opposite argument is "well, we always somehow advanced, it will never change", which is quite ridiculous. I mean, go ahead and SHOW ME an FTL drive or some 'magical' supply of fantastic amounts of energy. While we certainly don't know everything by a long shot we're coming closer and closer to a good approximation of understanding what is and isn't possible. There are NO indications whatsoever that FTL etc are possible. Without that sort of 'impossibilium' to power your objections you're basically left just throwing rocks at whatever I've said. That's fine, of course many people have been proven wrong in history, but I will predict now that the sort of 'technology' required is simply magic and can't exist. Again, I know my opinion is unpopular, but unpopular and wrong are not the same thing, or even related to each other.
Yes, of course that does ultimately come up at some level, the "then why bother to do anything in the first place" argument. HOWEVER, if you look at the human race's progress it seems to be almost exclusively in the direction of overall greater efficiency and an increase in our collective share of the energy throughput of the biosphere. We learned to chip flint and light fire because it was easier and more efficient. We learned to plant crops and hurd animals for the same reason, etc. This process might well continue up to a certain point. We can imagine a Solar System wide civilization with trade and so forth that might make economic sense. Once you hit the edge of the Solar System though the costs go up VASTLY. There simply is no conceivable economic argument left.
Now, individually people of course don't act entirely on the basis of economics, but stable societies don't continue to exist in the face of economic reality. They are quickly replaced by ones that DO live by their means. We have no examples at all of such behavior at the level of society, and it is hard to imagine a society in which individual whim is sufficient to spend the vast resources needed for interstellar travel. It seems almost conceivable as some sort of "great pyramid" kind of thing, but even looking at that, the Egyptians only built a very limited number of large pyramids in one tiny portion of their overall history as a great civilization. I'm still not seeing the example or the rationale where something like that would continue for long.
I'm simply explicating the SCALE of the power requirements for interstellar travel, which are clearly huge. It has NOTHING to do with the universe being "made of energy", it has to do with the amount of power you have available to you to use. By your reasoning the Earth is "made of energy" and thus the human race has no energy problem, right?
I answered what? Read it again. The Solar System is made up of nothing but hydrogen and helium basically, with a minor impurity of C, O, N, and a very minor contamination of other atoms. Every other system is made of that stuff too. As the author of the original blog pointed out, if you have the tech to cross interstellar space, then you clearly can simply make whatever you want out of what you have at home.
Yes, you could run out of matter, but do you realize how incredibly hard that would be? Jupiter has 1000x the mass of Earth. In fact Earth is a very tiny fraction of the mass of all the planets. By the time you were running out you'd be at Kardeshev level 2 (10+ orders of magnitude beyond using all the energy on Earth, which is many orders of magnitude beyond us), would you really need to GO anywhere for more? It seems kinda unlikely, and again would be a bad investment (you'd never get the energy invested back).
And we don't need ANY arguments about what such beings would be like in order to understand that there is nothing unique here to want. The Solar System is composed of approximately 99.95% hydrogen and helium. This is basically the same as the composition of the rest of the Universe. While some elements may be slightly more common or concentrated in slightly more convenient forms in one place than another there simply isn't anything particularly unique in one star system that isn't present in another.
Furthermore look at the energetics of interstellar space travel. "Accelerating one ton to one-tenth of the speed of light requires at least 450 PJ or 4.5 ×10^17 J or 125 billion kWh, without factoring in efficiency of the propulsion mechanism. This energy has to be either generated on-board from stored fuel, harvested from the interstellar medium, or projected over immense distances." -- Wikipedia. In 2008 the world used roughly 474×10^18 J, which means the entire power output of the human race for a year would suffice to accelerate one starship of 40 tons to 0.1C, roughly. This is about the weight of the 'J' class Apollo Lunar mission payload (LEM, CM, SM, etc). Clearly even the most limited interstellar travel would have an energy cost that is frankly hard to imagine.
So, considering the enormous cost and the high degree of technology required to traverse interstellar space, why bother? Certainly it can never be economical. The energy costs quoted above indicate that even the most expensive conceivable processes for making things would be cheaper (IE using solar power to perform nuclear reactions to transmute one element into whatever other ones you need and then make whatever you want out of it) than traveling to where you can find something.
Clearly a civilization could in principle literally consume all matter in its vicinity. It is hard to imagine how this would lead to expansion for economic reasons though, there'd never be any hope of getting a return on your investment.
Obviously someone can always invent some new hypothesis as to why, for reasons of alien psychology, aliens would want to travel, but nobody knows squat about alien psychology, so there's really no point in debating it. The very fact that such an undertaking would be VAST in scope, significant even for a Kardeshev level 2 civilization indicates it wouldn't be carried out on some whim, and it seems unlikely that a civilization which spent its energy so profligately on whims would survive long.
I know it isn't a real popular opinion to hold, but everything I see indicates that interstellar distances are pretty close to uncrossable for physical beings like humans. Frankly I think that is the plain answer to the whole Fermi Paradox that people just don't really want to come to grips with. The gulfs between the stars are so wide that nobody crosses them, EVER.
While the angular resolution of IceCube is not GREAT it DOES detect the direction from which the particles it detects came. This happens because, as others pointed out, the neutrino has a momentum. When it slams into a nucleus in the dectector the resulting collision debris carries away that momentum, thus the velocities of those particles, which are easily determined allows an estimate of the velocity of the original neutrino and thus its point of origin in the sky.
Of course the distance it came from is not readily determined, but if there's nothing terribly energetic nearby, then presumably you're looking at something from further away, and when we're talking about PeV neutrinos it has to be VERY energetic, not something we'd likely miss if it was nearby. Remember, we detected 2 neutrinos, that means there were literally trillions more (well, far more than that probably) that simply passed on through the detector with the same energies.
I think if you peruse the literature on the subject, NOT the popular literature, you will find that the evidence for this 'logical left brain' is actually non-existent. I'm not saying you're not logical etc, but it isn't ESPECIALLY because of being left brained. To a large extent the actual scientific evidence shows each hemisphere performing largely the same functions in mostly the same way. Its an interesting topic, but in the process of popularizing neuroscience the science press has, as usual, vastly overhyped certain observations. Observations I would add that were so preliminary and hard to interpret that they never should have been given any real credence. This myth is now firmly embedded in pop science, but it is bunk, just like "sugar makes children hyper" and other such nonsense.
Meh, the whole "left brain/right brain" thing is pretty heavily overblown. There are subtle differences, but probably not super drastic. It would be interesting to study various forms of vision defects WRT cognition though.
Yeah, I agree. In fact much beyond 5 feet I don't think there's much difference. Out to arms length its a serious factor, now and then I misjudge something. The only time it matters really any past 5 feet is fast moving objects. I can't play any sort of ball sport at all really, though I have excellent aim I can't catch all that well. Playing tennis would be a sad joke.
The other thing that I would note is that poor lighting conditions are treacherous. In moonlight or thereabouts the world becomes nothing but a bunch of flat grey areas of varying tone, that can be 'interesting'.
Well, everyone is different. Beyond that there are a number of different conditions that people often confuse under the term "lazy eye". True Amblyopia is different from divergence, and they won't necessarily respond to the same treatments. What I have is a basic divergence, which is pretty common, except for some reason mine only developed when I was in high school. Basically I was advised that as long as my vision worked and I didn't suffer any overt visual problems (aside from the loss of depth perception) that I was better off not messing with it. In fact several specialists who've looked at me have begged off on surgery. I've done a lot of eye exercises, but that seems to have fairly limited benefits. Honestly, aside from the cosmetic issue which doesn't bother me that much, there's not a whole lot of reason to try to fix my condition.
The Oculus Rift thing does sound interesting though, that might be a nice technology for helping some people.
Well, I personally wrote much of a whole family of multi-million line applications which were designed to validate the design of Fuel/Center of Gravity Measurement Systems, and then extended to provide emulation of the entire avionics suites of several aircraft. The same tool set was also used for functional test on the production line of both FRU and SRU level components (cards and entire boxes) for said aircraft, as well as forming the basis of the depot-level test system for F/CGMS and later other avionics SRUs (navigation systems, radios, etc). These were all LARGE complex pieces of software with complex UIs, integration of large amounts of hardware, coding and decoding of large amounts of data in real time, etc.
Pretty much every astronomical observatory on Earth runs its telescopes using FORTH, and has since the 1970's. The standard pointing and control libraries are all FORTH vocabularies. I couldn't tell you how large these things are, I've only used a few of the libraries, but they're pretty decent sized applications.
Remember, FORTH in its native state IS an operating system. Multi-Forth is quite large and of course mostly written in itself, providing all the facilities expected of any modern OS, or did the last time I worked with it.
FORTH has been used in a huge number of other applications as well. For instance RCA 1802 Cardiac Monitor, MANY industrial control applications, The 500 computer networked Facility Management System which ran the King Khaled International Airport in Ryadh, etc. The pads that are used by Fedex drivers for package tracking are FORTH-based devices for instance. It has been used in quite a few satellites due to ease of testing, simplicity, and reliability, as well as ISS and STS payload control systems.
In my experience FORTH is still quite popular in industrial test and validation systems, many embedded applications, etc. While its use has never been overwhelmingly prevalent to my knowledge in anything except astronomical hardware control it has remained in service due to its simplicity, portability, extremely small hardware footprint, and ease of use for over 50 years with only small changes. At this point COBOL and FORTRAN are probably the only other 2 similar tools still in use, and modern versions of either of them bear only passing resemblance to their 1960's counterparts. GForth OTOH will happily compile and run source written 30 years ago barring some poor coding practices perhaps.
It isn't fashionable, but it never was the tool of people who cared about fashion, just about getting shit done in the simplest and best way possible. Certainly your experience with FORTH is IMHO a little limited and you are certainly far too eager to dismiss it as a toy, which it certainly isn't. If you ask me the world's software engineers could badly use a few lessons from Charlie Moore. It would certainly do most of them a lot of good to go do a port of FigFORTH, and read Leo Brodie's excellent books on FORTH programming. I know that the things I learned at that stage of my career were the most valuable part of my education in the art and science of software engineering.
Sorry, my experience is very different than yours. Doing simple data structures is hellish (comma operator?). You need to build the entire structure of your program up from scratch, because the language doesn't offer ANYTHING except its elegant, minimal syntax, memory peek and poke, and a few other primitives. My view is that programming in FORTH is like programming in assembler, except that you need to use reverse polish notation. There have actually been systems built to run FORTH directly, encoding the primitive words into microcode. As such, it really IS assembler. (I guess you could say the same thing about lisp and C, though).
Hmmm, not sure what FORTH you were using. Even the FORTHs I was using in the 80's were far more feature rich than that. We added all sorts of things like classes, structs, etc (mostly on our own back then, but today if you say use gnu gforth or etc you'll get all that stuff for free), there are also local variables and other niceties for when you want them. Hooks to industry standard libraries or just C/C++ libraries, system calls, etc are all long since standard features. Of course you're running under an OS to use that stuff, but it has clear advantages, and frankly nobody would want to write even a simple console video driver to run on bare metal, those days are over. And yes, you could say the same about C, FORTH is at about the same level of abstraction, in general, but you can create much higher level constructs too, which C is less suited to. One thing to remember is that in FORTH you have total control of the PARSER, which means you can quickly write little ASLs (most can be done simply with some clever FORTH programming actually). For instance our avionics system validation/test environment had commands along the lines of "ALTITUDE 50000 FEET LEFT WING TANK HALF FULL RIGHT WING TANK 4500 POUNDS LANDING GEAR UP, etc, very natural for a test engineer.
Also, you'll need to back up those claims of speed. You could also say that, statement for statement, assembler is far faster than C. Try comparing it to python based on functionality. I'm guessing that a moderately complex one-liner in python, perhaps involving a big list comprehension, will take hundreds of words of FORTH to replicate. Also, the FORTH will be slower, because the python has been optimized to hell, but the FORTH has been hand coded by somebody who just wants to get to the next problem. The FORTH will require you to remember the 17 parameters on the stack, and to ensure that they get pushed popped, swapped, and duped in exactly the right order. If you mess up, you'll be debugging for hours.
I'm pretty sure that any modern FORTH will compare quite nicely to Python in all respects. In my experience FORTH is AT LEAST as fast as well-written C code. Its impossible to estimate what will take 100s of FORTH words, I can write a parser in 5-10 lines of FORTH, that would take easily 1000's of lines of Python, and probably require advanced tools as well. There is a perfectly functional FORTH 1-liner that implements a web server in gforth. The thing you miss in terms of speed is that the way you write FORTH is itself so highly optimal that your code is extremely fast, and again nowadays there is both static/keyhole optimizing and dynamic optimizing going on. Look into it, you'd be surprised. The thing is the utter simplicity and transparency of the FORTH runtime means that it is very easy to optimize for.
As for 17 things on the stack, WTF? What sort of horrible coding practice are you into? That would be like passing 17 arguments to a subroutine in any other language, its ridiculous. If you understand good FORTH coding practice (write MANY short simple expressive words) then you will have no problem debugging your code. You'll have 1000's of 1-5 line functions that each do a very specific little bit of stuff and are super easy to test. Remember, I really DID write about a million lines a year of this stuff, add it up, its hard for most people to type that fast. You just do it s
I just found it curious that you limited yourself to one specific set of languages, and not ones that are really IME THAT effective in an interactive interpreted mode. I mean yes, you can run perl that way too, but its not pretty. FORTH OTOH was built from the ground up for exactly that purpose, to BE an interactive development environment all of it is own. Granted, people may feel more comfortable with more modern traditional syntax of course, but it REALLY is hard to beat the RPN style of FORTH interactively, and its hard to beat for code modularity. It tends to be really easy and natural to write small 5 line snippets and then convert them into words. So, it seemed quite related.
Well, I don't really agree that there ARE 'massive problems'. He can say "parsers are complex" and as an old FORTH guy I'm ALL for simplicity, no doubt at all about that, yet IME I'd rather put a bit more smarts and complexity into my data structures sometimes. The parser may be a bit complicated but it really IS a black box. Readability is a nice feature too. One can build non-xml configuration file formats for instance, but for SOME tasks building one in XML really is a good choice, so things like commons-configuration are worthwhile, though complex. Of course there are other notations you CAN use YAML, ASN, etc. They have their virtues. I think the real answer is that absolute statements are rarely wisdom in all of IT, its a broad field.
ROFL! You of course understand that HL7 V3 messaging and HL7 CDA ARE XML? No? Oops! SAIF interoperability also pretty well envisages SOAP based service orchestration. I built a demo for the CHS a couple years ago which was entirely built using SAIF based architecture, CDA, etc all over SOAP services on top of JBoss-WS and some custom framework. Easy actually, we demonstrated interoperability between provider and back-end systems, workflows, security models, and other aspects of a large-scale system.
HL7 has of course been around for since the mid 90's and has promulgated various messaging and transport protocols which are non-XML, Arden and MLLP in particular, but I'd note that those are no longer particularly relevant to current practice and in fact saw relatively limited use.
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Its a discussion thread, if it is 'spoiled' by there being more than one side to the discussion then all of /. is utterly pointless, just go talk to yourself! lol.
As for who says, energy says. It would take a monster amount of energy (read above) to travel to another star system. Surely such vast quantities of energy are far beyond what any individual would ever need. Thus it seems unlikely to me that one or a few people would ever possess by themselves the means and authority to deploy such large resources to such a project. If an entire civilization (or a large part of it) is both so impractical and so empowered that it would do such a thing then isn't it vastly more likely such a civilization would simply do something stupid and wipe itself out due to its own impracticality? That's the whole nut of the "scale beyond a few individuals" because if the whole society is insane then yes indeed they might dream of interstellar travel, but they're not going to be in a position to achieve it.
But again, what rational species would finance such a trip? The return on investment couldn't possibly make it worthwhile. A race which was so impractical in its outlook that it would expend vast resources with no return is unlikely to survive and prosper to the level of building starships, is it not?
Beyond that I think the 'slow road' is not such an easy thing. Even 0.1C is a HUGE amount of energy, as I calculated above, but going slower creates other obvious problems. To create a 'mechanism' (in the most general sense of the word) which would remain functional over 100's, 1000's, or 10's of thousands of years is far more difficult to imagine than sci-fi authors seem to think. Entropy is the enemy of everything, and the more complicated you have to make your mechanism in order to supply it with means to deal with more and more situations (remember, more and more unlikely problems will become significant factors over long stretches of time) the more failure prone it becomes. Biological systems rarely remain intact for time periods beyond a few decades for instance. Imagine a mechanism which had to withstand the high radiation environment of a 0.1C trip to the nearest star system for 50+ years. Is this possible? Would the requirements for additional mass to enable acceptable reliability simply bloat the mission far beyond feasible limits? Can something so complex function at 100% duty cycle without spares or maintenance for 50 years, even with advanced technology? At best we're looking at an extraordinarily difficult engineering problem, one many orders of magnitude beyond what we are familiar with.
As I've said before though, interstellar travel doesn't have to be literally impossible. It just needs to be infeasible enough that an advanced civilization has better things to do with its resources than fling them into space to never see again. Even if it does happen once in a long while we'd be VERY unlikely to meet aliens unless such things were fairly commonplace, given the vast size of the Universe.
Yes, somewhere else which is made of TADA! More hydrogen and helium! The problem is that on even a modest scale the Universe is remarkably homogenous. Once you posit a high level of technology its hard to imagine a very good reason WHY you would want to spend the huge cost to travel to the stars. If one says "well just because" then you have to posit a VERY irrational intellect, and it is hard to imagine such an intellect being able to carry out a mission to the stars.
Sure, we can imagine making 3 kilos of antimatter. What we can't imagine is what would be worth paying the humongous cost for it. Even in a future where energy is plentiful an amount equal to the current total power output of the human race would be enough to do a LOT with (look at what we today can do with it and then imagine that power applied through a much more advanced technology).
Again though, we can imagine ANYTHING, but where are there any signs of 'direct conversion' in our understanding of nature? I mean certainly we understand things in only a partial way, but there are no signs of any phenomenon under which matter is converted to energy. When people cry that we have all sorts of examples of technology 'nobody would have predicted before' I have to be pretty skeptical. People predicted and experimented with powered heavier-than-air flight for millenia for instance, and even achieved some limited success, certainly they had some idea of how to achieve it. Likewise with other technologies such as steam power, electricity, etc. Certainly Volta wouldn't have predicted micro-electronics and wouldn't be able to explain them with the physics he had at his disposal, but if you gave him a computer he'd probably correctly assert that it was an electrically based device, and people certainly did predict computers etc long before they became available. We have not even a wiff of a hint about things like 'direct conversion' today. If such a thing is possible it is FAR beyond us. Again, we could simply imagine such things from whole cloth, but that's just magical thinking, it doesn't really belong in a discussion of what is actually feasible and likely.
Yeah, I think the various AC's that have responded already have summarized things nicely, to reiterate:
1) FTL is LOGICALLY impossible. This is off the table. We may not fully understand the way the universe works but we have logically demonstrated that either there is FTL and no causality and no common universal laws of physics which apply within every reference frame equally (IE the laws of physics would change whenever you accellerated) or FTL is impossible. No appeal to "we don't know enough, we're ignorant" can get around this, Einstein did not leave ANY 'get out of jail free card' ways to get around it. No, not wormholes, they'd break down causality too, nor the 'Alcubierre Drive' which ALSO breaks down causality, etc. You can try to assume there are some sort of parallel worlds or something you can access via some handwavium tech, but frankly why not just posit that the right ritual enacted at the right phase of the Moon will open a door into Elfland? Nobody can EVER 'prove' such things don't exist, but you care to bet?
2) As for the "well, things always seem difficult until we do them", I would just like to point out what the 2nd AC said "...if it's at all possible, represents an intellectual and operational barrier an order of magnitude higher than anything mankind has encountered so far." except said AC is wrong in one sense. It isn't AN order of magnitude harder. All the list of things that were listed by JWSmythe above are maybe an order of magnitude, at most, harder than things that were done before them. Going from being able to travel to Mars to being able to travel to Alpha Centauri in something even roughly like the same time frame (IE less than a decades long journey) with a human crew is 12 orders of magnitude harder. Not ONE but TWELVE.
That's the thing people regularly fail to understand. They've been brought up on a steady diet of space opera/Star Trek where starships woosh around through space like its nothing and a trip to the next star system is like a jaunt to the next highway exit. THAT is surely fantasy. Even if some sort of FTL, or something nearly as good, proved to exist it would perforce have to be incredibly difficult to achieve, else natural phenomena would already exist which recapitulated the necessary phenomena for us to observe. The energies required must be beyond even what is achieved in the presence of billion solar mass black holes and such. No hint of such things is evident.
Perhaps our Universe was created by a prankster. It certainly seems like the limitations we face are such that the promise of surmounting them must always seem barely out of reach, but I think the prankster did a good job.
The point is, if you have the technology to do interstellar travel then you have the technology to make a 'pelt' or some 'gold' or whatever out of any matter you can get hold of, and it would be FAR FAR cheaper than transporting it across interstellar space. The economics can never make sense.
The colonization of North America is just not analogous. Suppose it took 40 years to sail from London to Manhatten and the cost of a single ship was as much as the entire GDP of Europe in 1700. There's no bloody chance at all that such a colonization would have ever taken place. Nor would a few troublemakers like the Pilgrims have had the wherewithall to hire such a ship to haul them across. Nor is it at all likely they would have survived when they got there without the eventual arrival of additional ships, etc.
I'm not 100% sure we can ever economically justify colonizing the Moon, though it seems likely, but some other Solar System which is a TRILLION TIMES further than Mars, a place we can barely imagine being at the very outermost edge of our current capabilities (and another place I can't really see ever being economical to colonize, though scientific exploration seems quite likely). A trillion times harder than just about too hard is beyond too hard, it is beyond even "what the hell, we'll learn something" hard. There's just no imagining with a practical imagination anyone finding a 'pelt' or a 'mineral' so unique and valuable that it would be worth many times over the total current power output of the human race to send it back.
Agreed. The question is who would take the leap across the great gulf when there are always much cheaper ways of getting more matter, even if you hve to take it from someone else? At best all the sponsors of such a mission can hope to get back is information, but as the author of the blog piece says, eventually there just isn't that much more to know that's really all that valuable that its worth going all that way at all that expense to get.
In terms of "why haven't we met anyone" (the Fermi Paradox) though we really don't need to assume that interstellar travel is NEVER undertaken, only that it is modestly rare. If intelligent life itself is fairly uncommon (probably not an unreasonable assumption, certainly plausible) then we could easily see ourselves being the only active intelligent species in the galaxy at this time.
It may be that simple curiousity and a drive to spread exists in some species to a degree which does drive them across the galaxy. Unlike many I'm not as sanguine about the ease of such a species becoming ubiquitous. Travel itself may be slower and more difficult than we imagine with a high cost and high rate of failure. Coupled with a moderately short survival time for technological civilizations might mean that each colony/Von Neuman probe on average produces less than one or only right about one offspring. It could then take vastly longer than the half-life of a species to explore a large part of the galaxy. In that scenario it may be that there are regions which are explored and 'occupied' in some sense for a time, but much/most of the galaxy remains virgin.
Even if these interstellar civilizations were moderately common the gulf of TIME is very large. If each lasts only a small handful of millions of years then most of time is empty of them. I really doubt that the artifacts of such a civilization would remain in any easily discoverable form for more than a few million years at most.
Thus in effect its easy to postulate we could be pretty much completely alone even without assuming the absolute infeasibility of interstellar travel. It just needs to be difficult and expensive. From where I stand it seems like that's exactly what it is! Even some advanced machine race which can make highly durable 'bodies' and has reached Kardeshev level 2 might not be able to spread all through the galaxy, or last very long.
No, actually they don't. Not on any scale larger than that which can be undertaken by a few individuals. Beyond that our activities, on a 'society scale' are quite practical. The exceptions are quite informative. The ancient Egyptians employed 1000s of people to build giant pyramids, for less than one century before their society collapsed. When it recovered they built much smaller underground tombs for the next 2000 or so years, never again building a large pyramid. Other 'whimsical' projects were on much smaller scales. In fact no building exceeded the size of the Great Pyramid of Cheops until the 20th Century (the Eiffel Tower was the first to equal it in height). Considering the crude technology at hand we could safely hypothesize that the Great Pyramid is pretty much unique in history. Certainly interstellar travel would necessarily entail a vast and prolonged effort by an entire society on a huge scale. History isn't especially sanguine about the likelihood of that happening.
Yes, in other words, "Its impossible, but let me imagine if it wasn't". Were such 'shifts' possible the laws of nature as we know them would be utterly overthrown. Again, I know, its not a popular opinion and you can always wave your hands and imagine some other imagining, but we can only extrapolate from what we know, not what we wish.
Yep, and you're the one that should get those mod points! (too bad, I even have some, can't use them here).
Yes, yes, well what are you doing? At best the opposite argument is "well, we always somehow advanced, it will never change", which is quite ridiculous. I mean, go ahead and SHOW ME an FTL drive or some 'magical' supply of fantastic amounts of energy. While we certainly don't know everything by a long shot we're coming closer and closer to a good approximation of understanding what is and isn't possible. There are NO indications whatsoever that FTL etc are possible. Without that sort of 'impossibilium' to power your objections you're basically left just throwing rocks at whatever I've said. That's fine, of course many people have been proven wrong in history, but I will predict now that the sort of 'technology' required is simply magic and can't exist. Again, I know my opinion is unpopular, but unpopular and wrong are not the same thing, or even related to each other.
Yes, of course that does ultimately come up at some level, the "then why bother to do anything in the first place" argument. HOWEVER, if you look at the human race's progress it seems to be almost exclusively in the direction of overall greater efficiency and an increase in our collective share of the energy throughput of the biosphere. We learned to chip flint and light fire because it was easier and more efficient. We learned to plant crops and hurd animals for the same reason, etc. This process might well continue up to a certain point. We can imagine a Solar System wide civilization with trade and so forth that might make economic sense. Once you hit the edge of the Solar System though the costs go up VASTLY. There simply is no conceivable economic argument left.
Now, individually people of course don't act entirely on the basis of economics, but stable societies don't continue to exist in the face of economic reality. They are quickly replaced by ones that DO live by their means. We have no examples at all of such behavior at the level of society, and it is hard to imagine a society in which individual whim is sufficient to spend the vast resources needed for interstellar travel. It seems almost conceivable as some sort of "great pyramid" kind of thing, but even looking at that, the Egyptians only built a very limited number of large pyramids in one tiny portion of their overall history as a great civilization. I'm still not seeing the example or the rationale where something like that would continue for long.
I'm simply explicating the SCALE of the power requirements for interstellar travel, which are clearly huge. It has NOTHING to do with the universe being "made of energy", it has to do with the amount of power you have available to you to use. By your reasoning the Earth is "made of energy" and thus the human race has no energy problem, right?
I answered what? Read it again. The Solar System is made up of nothing but hydrogen and helium basically, with a minor impurity of C, O, N, and a very minor contamination of other atoms. Every other system is made of that stuff too. As the author of the original blog pointed out, if you have the tech to cross interstellar space, then you clearly can simply make whatever you want out of what you have at home.
Yes, you could run out of matter, but do you realize how incredibly hard that would be? Jupiter has 1000x the mass of Earth. In fact Earth is a very tiny fraction of the mass of all the planets. By the time you were running out you'd be at Kardeshev level 2 (10+ orders of magnitude beyond using all the energy on Earth, which is many orders of magnitude beyond us), would you really need to GO anywhere for more? It seems kinda unlikely, and again would be a bad investment (you'd never get the energy invested back).
And we don't need ANY arguments about what such beings would be like in order to understand that there is nothing unique here to want. The Solar System is composed of approximately 99.95% hydrogen and helium. This is basically the same as the composition of the rest of the Universe. While some elements may be slightly more common or concentrated in slightly more convenient forms in one place than another there simply isn't anything particularly unique in one star system that isn't present in another.
Furthermore look at the energetics of interstellar space travel. "Accelerating one ton to one-tenth of the speed of light requires at least 450 PJ or 4.5 ×10^17 J or 125 billion kWh, without factoring in efficiency of the propulsion mechanism. This energy has to be either generated on-board from stored fuel, harvested from the interstellar medium, or projected over immense distances." -- Wikipedia. In 2008 the world used roughly 474×10^18 J, which means the entire power output of the human race for a year would suffice to accelerate one starship of 40 tons to 0.1C, roughly. This is about the weight of the 'J' class Apollo Lunar mission payload (LEM, CM, SM, etc). Clearly even the most limited interstellar travel would have an energy cost that is frankly hard to imagine.
So, considering the enormous cost and the high degree of technology required to traverse interstellar space, why bother? Certainly it can never be economical. The energy costs quoted above indicate that even the most expensive conceivable processes for making things would be cheaper (IE using solar power to perform nuclear reactions to transmute one element into whatever other ones you need and then make whatever you want out of it) than traveling to where you can find something.
Clearly a civilization could in principle literally consume all matter in its vicinity. It is hard to imagine how this would lead to expansion for economic reasons though, there'd never be any hope of getting a return on your investment.
Obviously someone can always invent some new hypothesis as to why, for reasons of alien psychology, aliens would want to travel, but nobody knows squat about alien psychology, so there's really no point in debating it. The very fact that such an undertaking would be VAST in scope, significant even for a Kardeshev level 2 civilization indicates it wouldn't be carried out on some whim, and it seems unlikely that a civilization which spent its energy so profligately on whims would survive long.
I know it isn't a real popular opinion to hold, but everything I see indicates that interstellar distances are pretty close to uncrossable for physical beings like humans. Frankly I think that is the plain answer to the whole Fermi Paradox that people just don't really want to come to grips with. The gulfs between the stars are so wide that nobody crosses them, EVER.
While the angular resolution of IceCube is not GREAT it DOES detect the direction from which the particles it detects came. This happens because, as others pointed out, the neutrino has a momentum. When it slams into a nucleus in the dectector the resulting collision debris carries away that momentum, thus the velocities of those particles, which are easily determined allows an estimate of the velocity of the original neutrino and thus its point of origin in the sky.
Of course the distance it came from is not readily determined, but if there's nothing terribly energetic nearby, then presumably you're looking at something from further away, and when we're talking about PeV neutrinos it has to be VERY energetic, not something we'd likely miss if it was nearby. Remember, we detected 2 neutrinos, that means there were literally trillions more (well, far more than that probably) that simply passed on through the detector with the same energies.
I think if you peruse the literature on the subject, NOT the popular literature, you will find that the evidence for this 'logical left brain' is actually non-existent. I'm not saying you're not logical etc, but it isn't ESPECIALLY because of being left brained. To a large extent the actual scientific evidence shows each hemisphere performing largely the same functions in mostly the same way. Its an interesting topic, but in the process of popularizing neuroscience the science press has, as usual, vastly overhyped certain observations. Observations I would add that were so preliminary and hard to interpret that they never should have been given any real credence. This myth is now firmly embedded in pop science, but it is bunk, just like "sugar makes children hyper" and other such nonsense.
Yeah, Data is not the plural of Annecdote...
Meh, the whole "left brain/right brain" thing is pretty heavily overblown. There are subtle differences, but probably not super drastic. It would be interesting to study various forms of vision defects WRT cognition though.
Yeah, I agree. In fact much beyond 5 feet I don't think there's much difference. Out to arms length its a serious factor, now and then I misjudge something. The only time it matters really any past 5 feet is fast moving objects. I can't play any sort of ball sport at all really, though I have excellent aim I can't catch all that well. Playing tennis would be a sad joke.
The other thing that I would note is that poor lighting conditions are treacherous. In moonlight or thereabouts the world becomes nothing but a bunch of flat grey areas of varying tone, that can be 'interesting'.
Well, everyone is different. Beyond that there are a number of different conditions that people often confuse under the term "lazy eye". True Amblyopia is different from divergence, and they won't necessarily respond to the same treatments. What I have is a basic divergence, which is pretty common, except for some reason mine only developed when I was in high school. Basically I was advised that as long as my vision worked and I didn't suffer any overt visual problems (aside from the loss of depth perception) that I was better off not messing with it. In fact several specialists who've looked at me have begged off on surgery. I've done a lot of eye exercises, but that seems to have fairly limited benefits. Honestly, aside from the cosmetic issue which doesn't bother me that much, there's not a whole lot of reason to try to fix my condition.
The Oculus Rift thing does sound interesting though, that might be a nice technology for helping some people.
Well, I personally wrote much of a whole family of multi-million line applications which were designed to validate the design of Fuel/Center of Gravity Measurement Systems, and then extended to provide emulation of the entire avionics suites of several aircraft. The same tool set was also used for functional test on the production line of both FRU and SRU level components (cards and entire boxes) for said aircraft, as well as forming the basis of the depot-level test system for F/CGMS and later other avionics SRUs (navigation systems, radios, etc). These were all LARGE complex pieces of software with complex UIs, integration of large amounts of hardware, coding and decoding of large amounts of data in real time, etc.
Pretty much every astronomical observatory on Earth runs its telescopes using FORTH, and has since the 1970's. The standard pointing and control libraries are all FORTH vocabularies. I couldn't tell you how large these things are, I've only used a few of the libraries, but they're pretty decent sized applications.
Remember, FORTH in its native state IS an operating system. Multi-Forth is quite large and of course mostly written in itself, providing all the facilities expected of any modern OS, or did the last time I worked with it.
FORTH has been used in a huge number of other applications as well. For instance RCA 1802 Cardiac Monitor, MANY industrial control applications, The 500 computer networked Facility Management System which ran the King Khaled International Airport in Ryadh, etc. The pads that are used by Fedex drivers for package tracking are FORTH-based devices for instance. It has been used in quite a few satellites due to ease of testing, simplicity, and reliability, as well as ISS and STS payload control systems.
In my experience FORTH is still quite popular in industrial test and validation systems, many embedded applications, etc. While its use has never been overwhelmingly prevalent to my knowledge in anything except astronomical hardware control it has remained in service due to its simplicity, portability, extremely small hardware footprint, and ease of use for over 50 years with only small changes. At this point COBOL and FORTRAN are probably the only other 2 similar tools still in use, and modern versions of either of them bear only passing resemblance to their 1960's counterparts. GForth OTOH will happily compile and run source written 30 years ago barring some poor coding practices perhaps.
It isn't fashionable, but it never was the tool of people who cared about fashion, just about getting shit done in the simplest and best way possible. Certainly your experience with FORTH is IMHO a little limited and you are certainly far too eager to dismiss it as a toy, which it certainly isn't. If you ask me the world's software engineers could badly use a few lessons from Charlie Moore. It would certainly do most of them a lot of good to go do a port of FigFORTH, and read Leo Brodie's excellent books on FORTH programming. I know that the things I learned at that stage of my career were the most valuable part of my education in the art and science of software engineering.
Sorry, my experience is very different than yours. Doing simple data structures is hellish (comma operator?). You need to build the entire structure of your program up from scratch, because the language doesn't offer ANYTHING except its elegant, minimal syntax, memory peek and poke, and a few other primitives. My view is that programming in FORTH is like programming in assembler, except that you need to use reverse polish notation. There have actually been systems built to run FORTH directly, encoding the primitive words into microcode. As such, it really IS assembler. (I guess you could say the same thing about lisp and C, though).
Hmmm, not sure what FORTH you were using. Even the FORTHs I was using in the 80's were far more feature rich than that. We added all sorts of things like classes, structs, etc (mostly on our own back then, but today if you say use gnu gforth or etc you'll get all that stuff for free), there are also local variables and other niceties for when you want them. Hooks to industry standard libraries or just C/C++ libraries, system calls, etc are all long since standard features. Of course you're running under an OS to use that stuff, but it has clear advantages, and frankly nobody would want to write even a simple console video driver to run on bare metal, those days are over. And yes, you could say the same about C, FORTH is at about the same level of abstraction, in general, but you can create much higher level constructs too, which C is less suited to. One thing to remember is that in FORTH you have total control of the PARSER, which means you can quickly write little ASLs (most can be done simply with some clever FORTH programming actually). For instance our avionics system validation/test environment had commands along the lines of "ALTITUDE 50000 FEET LEFT WING TANK HALF FULL RIGHT WING TANK 4500 POUNDS LANDING GEAR UP, etc, very natural for a test engineer.
Also, you'll need to back up those claims of speed. You could also say that, statement for statement, assembler is far faster than C. Try comparing it to python based on functionality. I'm guessing that a moderately complex one-liner in python, perhaps involving a big list comprehension, will take hundreds of words of FORTH to replicate. Also, the FORTH will be slower, because the python has been optimized to hell, but the FORTH has been hand coded by somebody who just wants to get to the next problem. The FORTH will require you to remember the 17 parameters on the stack, and to ensure that they get pushed popped, swapped, and duped in exactly the right order. If you mess up, you'll be debugging for hours.
I'm pretty sure that any modern FORTH will compare quite nicely to Python in all respects. In my experience FORTH is AT LEAST as fast as well-written C code. Its impossible to estimate what will take 100s of FORTH words, I can write a parser in 5-10 lines of FORTH, that would take easily 1000's of lines of Python, and probably require advanced tools as well. There is a perfectly functional FORTH 1-liner that implements a web server in gforth. The thing you miss in terms of speed is that the way you write FORTH is itself so highly optimal that your code is extremely fast, and again nowadays there is both static/keyhole optimizing and dynamic optimizing going on. Look into it, you'd be surprised. The thing is the utter simplicity and transparency of the FORTH runtime means that it is very easy to optimize for.
As for 17 things on the stack, WTF? What sort of horrible coding practice are you into? That would be like passing 17 arguments to a subroutine in any other language, its ridiculous. If you understand good FORTH coding practice (write MANY short simple expressive words) then you will have no problem debugging your code. You'll have 1000's of 1-5 line functions that each do a very specific little bit of stuff and are super easy to test. Remember, I really DID write about a million lines a year of this stuff, add it up, its hard for most people to type that fast. You just do it s
I just found it curious that you limited yourself to one specific set of languages, and not ones that are really IME THAT effective in an interactive interpreted mode. I mean yes, you can run perl that way too, but its not pretty. FORTH OTOH was built from the ground up for exactly that purpose, to BE an interactive development environment all of it is own. Granted, people may feel more comfortable with more modern traditional syntax of course, but it REALLY is hard to beat the RPN style of FORTH interactively, and its hard to beat for code modularity. It tends to be really easy and natural to write small 5 line snippets and then convert them into words. So, it seemed quite related.
Well, I don't really agree that there ARE 'massive problems'. He can say "parsers are complex" and as an old FORTH guy I'm ALL for simplicity, no doubt at all about that, yet IME I'd rather put a bit more smarts and complexity into my data structures sometimes. The parser may be a bit complicated but it really IS a black box. Readability is a nice feature too. One can build non-xml configuration file formats for instance, but for SOME tasks building one in XML really is a good choice, so things like commons-configuration are worthwhile, though complex. Of course there are other notations you CAN use YAML, ASN, etc. They have their virtues. I think the real answer is that absolute statements are rarely wisdom in all of IT, its a broad field.
ROFL! You of course understand that HL7 V3 messaging and HL7 CDA ARE XML? No? Oops! SAIF interoperability also pretty well envisages SOAP based service orchestration. I built a demo for the CHS a couple years ago which was entirely built using SAIF based architecture, CDA, etc all over SOAP services on top of JBoss-WS and some custom framework. Easy actually, we demonstrated interoperability between provider and back-end systems, workflows, security models, and other aspects of a large-scale system.
HL7 has of course been around for since the mid 90's and has promulgated various messaging and transport protocols which are non-XML, Arden and MLLP in particular, but I'd note that those are no longer particularly relevant to current practice and in fact saw relatively limited use.