Stories
Slash Boxes
Comments

SoylentNews is people

posted by Fnord666 on Wednesday August 30 2017, @07:54PM   Printer-friendly
from the must-read dept.

An Indian site, YourStory, has an unusually broad ranging interview with Richard Stallman. While much of the background and goals will already be familiar to SN readers, the interview is interesting not only for its scope but also that India is starting to take an interest in these matters.

To know Richard Stallman is to know the true meaning of freedom. He's the man behind the GNU project and the free software movement, and the subject of our Techie Tuesdays this week.

This is not a usual story. After multiple attempts to get in touch for an interaction with Richard Stallman, I got a response which prepared me well for what's coming next. I'm sharing the same with you to prepare you for what's coming next.

I'm willing to do the interview — if you can put yourself into philosophical and political mindset that is totally different from the one that the other articles are rooted in.

The general mindset of your articles is to admire success. Both business success, and engineering success. My values disagree fundamentally with that. In my view, proprietary software is an injustice; it is wrongdoing. People should be _ashamed_ of making proprietary software, _especially_ if it is successful. (If nobody uses the proprietary program, at least it has not really wronged anyone.) Thus, most of the projects you consider good, I consider bad.


Original Submission

 
This discussion has been archived. No new comments can be posted.
Display Options Threshold/Breakthrough Mark All as Read Mark All as Unread
The Fine Print: The following comments are owned by whoever posted them. We are not responsible for them in any way.
  • (Score: 2) by HiThere on Thursday August 31 2017, @05:37PM (10 children)

    by HiThere (866) Subscriber Badge on Thursday August 31 2017, @05:37PM (#562210) Journal

    I think you have to give up on uncharged cosmic rays. And shielding is just likely to increase the damage surface via secondary emissions. OTOH, they're a lot less of a problem than the others.
    Also, I wasn't even thinking of living on the surface of objects in space. Too many micro-meteorites around at too high a relative velocity. But that dust could be valuable if you could just catch it. Some of it's charged, that should be able to be handled. Some of it's ferro-magnetic. That should be able to be handled. It all depends on how flexible you can make the magnetic shielding. But some of the dust is uncharged and not ferro-magnetic, and you want a shield between you and it. So you need a thick rind on your habitat, and internal barriers against accidents. Use the outer layers for stores that don't mind the vacuum. Use the next inner layers for things like water, etc. The layer in from that for food storage. Then you come to living areas. Since gravity is probably needed, this will be the living quarters (you spin the place). Inner from that are work areas and the library, schools, etc. Inner from that is labs. Inner from that is rapid transit (actually that doesn't need a separate layer, but it benefits from light gravity and short distances, use elevators to get in and out. Inner from that is manufacturing...which isn't necessarily enclosed and extends all the way to the center. At the center there's an ion-rocket for moving around...not agile, but economical in fuel.

    Note this is just a rough sketch, and I'm not really committed to any part of the design, but this grows by increasing the height of the cylinder, until it makes sense to split it into two cylinders...possibly spinning at different rates, but still magnetically bonded with a zero friction link (so no direct material link). Clearly with this design you want your entry/exit ports to be on a non-rotating cylinder, and there may be a central core that is used to move freight between the cylinders. Calling it an elevator is too simplistic, but that's almost what it is, but it must contain mechanisms for isolating itself from various things rotating around it at various different speeds. You can think of it as magnetic levitation, but if done properly that's just a bumper that would only be used in case of emergency. But it needs to be in multiple isolated slices that can adjust their rotational speed to match either the core or the external shell.

    Too much detail, but it's definitely NOT living on the surface. Only planets, and not most of them, even permit living on the surface. Habitats on the moon would clearly need to be subsurface, and the same is probably true of Mars, once people think really hard about living there. And both cases need just as much life support as a space habitat with pluses and minuses. Gravity would be harder to deal with, but shielding would be easier (as there was more easily available material to use for shielding.

    --
    Javascript is what you use to allow unknown third parties to run software you have no idea about on your computer.
    Starting Score:    1  point
    Karma-Bonus Modifier   +1  

    Total Score:   2  
  • (Score: 2) by Immerman on Thursday August 31 2017, @09:58PM (9 children)

    by Immerman (3985) on Thursday August 31 2017, @09:58PM (#562313)

    Cosmic rays will kill you just as surely as the others, just not quite as quickly. But like I said, it's easy enough to shield against the same way we do here on Earth - cover yourself with several pounds per square inch of shielding. Not terribly viable for a space vehicle that you'd want to accelerate - in that case yeah, you just deal with all the baseline radiation rather than try to protect yourself and have to deal with the far worse secondary emissions from cosmic rays. And just try not to spend any more time than necessary exposed to it. But it's not an issue if living in a hollowed-out asteroid. Assuming a density comparable to basalt (1.74oz/in^3) it only requires 135 inches, or 11.3 feet to get roughly the same 14 lb/in^2 worth of shielding as we get here on Earth's surface.

    One of the designs I've played with is to hollow out a large region within the asteroid, and then put rotating habitats in that - you get the benefit of shielding, without having to hold an immense mass of spinning shielding together. You can then travel between habitats and the rest of the microgravity facilities within the asteroid by way of either axial "spinning airlocks", or via circular "elevator" railcars that run between the rim of the habitat and the surrounding rock, alternately matching speed with one or the other. Not a perfect solution, but it gets you up and running without massive up-front outlays for a huge facility, and gives relatively easy access between "gravity" zones and regions free of both "gravity" and the associated Coriolis effects.

    • (Score: 2) by HiThere on Friday September 01 2017, @05:53AM (8 children)

      by HiThere (866) Subscriber Badge on Friday September 01 2017, @05:53AM (#562419) Journal

      What proportion of cosmic rays are ionized out in space? IIUC almost all of them are, in which case a magnetic shield should be able to divert them. If I'm right then the only question is would the magnetic field needed to shield against them be so strong as to be just as dangerous,.. but a thin ferro-magnetic skin should shield against that.

      The problem is that we don't yet know how to generate the magnetic shield. Planets seem to show that if properly done it shouldn't consume significant energy, but IIUC right now we either need to use electro-magnets or super-conductors, neither of which is particularly energetically efficient.

      --
      Javascript is what you use to allow unknown third parties to run software you have no idea about on your computer.
      • (Score: 2) by Immerman on Friday September 01 2017, @01:04PM (7 children)

        by Immerman (3985) on Friday September 01 2017, @01:04PM (#562481)

        I believe many are ionized, so they could theoretically be diverted by a sufficiently powerful magnetic shield - but we're talking about momentums that often completely dwarf anything in our largest particle accelerators, so that even those insanely powerful and highly concentrated magnetic traps couldn't dramatically divert them. The Earth's paltry magnetic field can mostly handle the slow, heavily ionized solar wind, but has basically no effect whatsoever on cosmic rays.

        Also, I'm not sure there there's any evidence whatsoever that planets produce magnetic fields particularly efficiently - I think you're grossly overestimating the strength of the fields, and grossly underestimating the energies at work in planetary phenomena. Heck, just the tiny change in solar energy retention from our CO2 emissions traps a million times more incoming energy than was produced burning the hydrocarbons.

        • (Score: 2) by HiThere on Friday September 01 2017, @05:59PM (6 children)

          by HiThere (866) Subscriber Badge on Friday September 01 2017, @05:59PM (#562621) Journal

          Yes, but diversion is a LOT easier than stopping. So I think it might well work. Of course, we don't yet have a good magnetic shield to test it against.

          So with this supposition the question becomes "How dangerous are the neutral cosmic rays? The ways I can think of to ionize them are all clumsy, and most of them result in secondary radiation. (E.g. have multiple layers of shield with high capture cross-sections in the expected energy spectrum. [Could you just target the electrons of the neutral cosmic rays? Probably not, but if so this might possibly be made to work. I see no way, however, to avoid this being clumsy and expensive.

          The thing is, planetary fields aren't that strong, but they have a long reach. So they exert a small amount of force over a long distance of travel. As for efficiency....well, IIUC the evidence is that the planets magnetic fields are a side effect of internal flows of lightly charged magma. (And also IIUC this is a theory that doesn't have much in the way of experimental evidence. Mainly things like the Moon lost it's magnetic field at such and such a time and its core solidified at such and such a time....and these all depend on long chains of reasoning from small pieces of evidence.) But the theory, such as it is, doesn't seem to suggest that much energy is spent on maintaining the field. And permanent magnets tend to hold their charge with little reinforcement, and things that are moving tend to stay in motion unless stopped by friction, etc. So it wouldn't be beyond the bounds of reason that maintaining the field wouldn't require ANY input of energy. Things are rarely that perfect, however, and even with perfection any energy used in diverting objects would need to be repaid...though perhaps momentum transfer could be so arranged that diversion was symmetric. Etc.

          OTOH, I do tend to envision a space habitat based around a cylinder, so a rock shield isn't something I find unreasonable. I just want to minimize it, because any mass you use that way can't be used for extending the cylinder;

          --
          Javascript is what you use to allow unknown third parties to run software you have no idea about on your computer.
          • (Score: 2) by Immerman on Sunday September 03 2017, @04:57PM (5 children)

            by Immerman (3985) on Sunday September 03 2017, @04:57PM (#563181)

            Diversion *is* a lot easier - but the smaller the diversion, the greater the distance it needs to be done at, in a fairly linear inverse relationship. But magnetic fields fall off with the inverse cube of distance, making large-scale magnetic shields extremely problematic

            Yeah, if you could create a planetary strength-and-range magnetic field, with a tiny spaceship at the center, it might be enough to protect from ionized cosmic rays. Maybe. I'd have to work out the math to see if it's even within several orders of magnitude of strong enough, but it might be. Certainly if you assume the ship is the source, in which case the magnetic field nearby would likely make those in the LHC look like refrigerator magnets in comparison.

            As for maintaining the field - superconductive electromagnets are actually really good for that - the current will simply keep circulating when you cut the power source, with very low maintenance losses provided you can keep the superconductors cold enough. They still have working losses though, diverting a particle traveling at nearly the speed of light takes some small amount of energy, and that energy is permanently drained from the magnetic field (same thing happens with permanent magnets too)

            I will say for your cylindrical space habitat bias - do consider the size of asteroids available. There are hundreds of them 100km across, and several thousand more 10km across. We'd still run out eventually, but not for a while. Plus you've got that old square-cube law working in your favor: only the outer few yards needs to be shielding, while the interior can be almost entirely living and working spaces. Double the diameter and you get 8x as much living space while only requiring 4x as much shielding material.

            And just because I was curious as to how much you could actually fit within an asteroid: The US covers an area of 9.8 trillion square meters. Assume an average interfloor height of 5 m and that's about 50 trillion cubic meters - the volume of a sphere less than 46 kilometers across.

            Also - basically unrelated, I'd be tempted to put the water storage near the center, simply because it's so important - that's very likely your primary water and oxygen reserves, you don't want to risk it venting into space. Plus, zero-G swimming pool... Storing i as an ice shell might be an option if you were far enough from the sun, but just the body heat of the inhabitants would probably make active cooling necessary unless you were out near Nptune or something. I'd likely go for commerical/recreational districts in the outside rings: easier to evacuate in case of problems, and keeps people in the highest-gravity sections while they're at their most active, maximizing the benefit.

            • (Score: 2) by HiThere on Sunday September 03 2017, @11:54PM (4 children)

              by HiThere (866) Subscriber Badge on Sunday September 03 2017, @11:54PM (#563245) Journal

              Actually, the field from a single magnet falls off as the 4th power of the distance, because of the dual polarity. But this may possibly be finesses, and probable the field would need to be generated in a set of rings around the habitat rather than within the habitat, so the strongest part of the field would be external to the habitat. This might mitigate the need for a ferro-magnetic shield around it...of course, if the walls were made of steel that would be essentially irrelevant. If they were aluminum though, it would be a significantly different. Similarly for titanium, or glass with carbon fibers. (Glass with conductive fibers, though, might hold the shield in place. But if it were to require minimal electrical power for maintenance the fibers would need to be superconductors. But it would need to be a glass that wasn't too strongly affected by thermal stresses.)

              --
              Javascript is what you use to allow unknown third parties to run software you have no idea about on your computer.
              • (Score: 2) by Immerman on Monday September 04 2017, @04:09PM (3 children)

                by Immerman (3985) on Monday September 04 2017, @04:09PM (#563478)

                Do you have a source for that? Everything I've seen says magnetism falls off as 1/r^3. If we had magnetic monopoles they'd fall off as 1/r^2, the same as gravity, electrostatics, light intensity, and everything else that propagates through 3-dimensional space.

                • (Score: 2) by HiThere on Monday September 04 2017, @04:54PM (2 children)

                  by HiThere (866) Subscriber Badge on Monday September 04 2017, @04:54PM (#563489) Journal

                  Sorry, it's been a long time since physics. Now that you say so I remember that EM and gravity fall off as the square, so you are right, magnetism falls off as the cube. But that's only far enough away that you get the two poles acting about equally. When you get closer the computation becomes quite difficult as you're combining two "falls off as the square" effects which conflict with each other. As you approach one of the poles it becomes sufficiently dominant, that the other fades into insignificance. I think that was where that "4th power" effect came from.

                  What's really going on is difficult to model, which is why they always trot out that "lines of force" model, but what's really happening is more line induced magnetism reacting against two poles which each fall off as the square in strength, but which conflict. And the resultant effect depends on whether the particle is charged, ferro-magnetic, or para-magnetic. Or just unresponsive. And then there's the field created by a charge running along a wire, which produces a linear effect, but the line isn't usually straight. I never even tried to calculate from first principles how an electro-magnet field was generated. It was hard enough for a straight wire. (This was multiple decades ago, and that wasn't my main interest in physics. And I dropped out about the time they started using tensors.)

                  Anyway, that third power response is the effect you get at a distance from the magnet. When you get closer the effects become stronger and not evenly spread.

                  In a way it's sort of like "jerk". Nobody ever calculated the higher derivatives, they always stop with acceleration, but acceleration has to start, and that's a higher derivative. And that has to start, which is a higher derivative. The "jerk" at the start of acceleration actually theoretically has an infinite number of derivatives, each of which acts for a shorter period of time. But rate of change of acceleration is always something that happens for a very short period of time, for lots of very good reasons. So people tend to ignore it. But if it weren't for jerk, glass wouldn't break when you dropped it.

                  Now this seems to mean that a strong magnetic shield would need to have LOTS of magnetic poles, which may be impossible. OTOH, if it has lots of magnetic poles, the effect at a distance would be minor. So you may be right that it can't be done...but the situation is complex enough that I'm going to keep hoping it's doable. (How would one calculate the effects of a rotating magnetic field? Usually the speed of rotation is slow enough that this can be ignored, but one rotated electronically might be able to do it fast enough that...?? Or what about a pulsing one? That last, though, doesn't sound like a low energy solution.)

                  --
                  Javascript is what you use to allow unknown third parties to run software you have no idea about on your computer.
                  • (Score: 2) by HiThere on Monday September 04 2017, @04:56PM

                    by HiThere (866) Subscriber Badge on Monday September 04 2017, @04:56PM (#563490) Journal

                    Sorry, that was largely thinking out loud. I'm not really sure of ANY of that. As I said, it's been a long time since physics.

                    --
                    Javascript is what you use to allow unknown third parties to run software you have no idea about on your computer.
                  • (Score: 2) by Immerman on Monday September 04 2017, @08:21PM

                    by Immerman (3985) on Monday September 04 2017, @08:21PM (#563560)

                    No worries, I think out loud here a fair bit myself.

                    I think you're wrong about "jerk" though - firstly it's quite common to consider the rate of change of acceleration, mostly as a comfort thing. Elevators are a common example - some accelerate gradually, while others transition quite rapidly, giving a "stomach in your throat/feet" feeling. Where glass is concerned the problem is its rigidity, which means any impact with another rigid object will cause a spike of acceleration as the contacting point comes to a stop nearly instantly. Often considered as as an "impulse" a spike of infinite force for zero duration, that imparts a definite finite change in momentum. Hard drives have a similar weakness - that "20Gs of impact resistance" can easily be overcome by, say, tapping a screwdriver against its casing. Rigid body collisions invariable involve rather ridiculous momentary accelerations.