Separating really small objects of almost the same density as water (0.91â"0.96 g/cm3 - they are made from polyethylene) is not easy, and the fact is that they pass through all existing water treatment works. Plastics are in fact a serious environmental issue, 1) since they often leak hormone-like chemicals, and 2) because plastic objects are mostly not broken down into their chemical constituents, but instead break up to form very small plastic splinters and fibres. These are now found everywhere in our food chain; certainly in anything that starts life at sea: fish etc. We still don't quite know what harm they cause - the great worry is that thei will turn out to be as harmful as asbestos. Is it a good idea to allow the industry to pump these largely unnecessary products out, when it seems likely that it will cause massive problems for society down the line? Health problems cost society money, not just in form of hospitals, doctors etc, but also in lost productivity - prevention is better than cure, and it is also better for business in the long run.

Sand is a natural material, and the environment already knows how to deal with it. I don't know exactly why they prefer to use plastic, but I'll bet it has to do with thei short term profit. Maybe it is a selling point, or was - I remember when it was first introduced and you suddenly heard a lot about how harsh the old kind of toothpaste was to your teeth. In reality it is probably no more than a selling point, like the current craze for putting triclosan in everything - which doesn't actually kill bacteria, but is likely to harm our health in the long run (both directly and by breeding resistent bacteria; when will we bother to learn?)

25 years, you say? It feels longer, somehow. Don't worry, I can see everybody's eyes glaze over, so I won't go too far down memory lane, except to say that there was actually a time when when Windows was cool and fun to work with. By gods, it was a load of crap, back then, but fun to code for, for that very reason. I used to spend 90% of my time commenting out code sections until the latest, spectacular error went away; that was how I learned to program properly in C. There is nothing like having to debug Windows running in real mode to bring home the idea that you must always initialise variable and check returned pointers. I sometimes miss the "hardship" in a perverse sort of way.

I still can't get my head around this; a guy is allowed to hold off a vote on legislation by talking, because in the US there is a rule that makes it impossible to do what would happen in other, democratic nations, namely that a couple of bailiffs would gently lead him away until he regained his sense. In some cases this can mean that a vote cannot be held before a deadline, so in this situation a single bully can veto legislation that the majority wishes to pass. And this is applauded as a courageous act of ... what? And the defence of this practice is, no doubt, "freedom of speech"; funny how "freedom" so often mean "your right to do as you please", not "my right to stand up and give you a well deserved slap", figuratively speaking.

The real reason that this kind of idiocy is allowed, is not that it is about an important freedom, but simply that is does not matter in the bigger picture. It looks spectacular, if only because it is spectacularly boring, and it gives people the illusion that their freedoms are real, but the deals have already been done in the board rooms, where the real power lies.

I have recently come across a book that I begin to think everybody with an interest in - or even just an opinion about - politics should read: "Economics: The User's Guide". It isn't politically neutral, but it does present a very good and understandable overview of the essentials of economics - here's a wikipedia page about the author, Ha-Joon Chang:

http://en.wikipedia.org/wiki/H...

His view (among other things), and he argues it very well, is that libertarianism and the modern loathing against politicians and the state are largely the product of the influence of especially the massively expanding financial industry and other large industries, whose interest it is to get deregulation. He also points out that contrary to common belief, the economy has historically tended to grow under strong government regulation that aimed to level out inequality, whereas deregulation has normally introduced instability and stagnation. Read the book and use you own judgement; I think you will be less convinced about libertarianism afterwards.

Why do I suddenly jump this sort of thing here, you might reasonably ask. The thing is, people with a strong interest in technology are often people who at least aspire to cultivating a scientific outlook; ie. they are not religiously blinded to any alternative viewpoint and will not be afraid of changing their opinion, if the evidence is good. This book presents an overview of economics without all the pretensions of most of the theorists and makes it feel like something you might understand with a bit of common sense, and that understanding will help anybody form a considered opinion about politics, as opposed to what is really just a form of quasi-religious clap-trap.

The assumption of GR is that space/time can be described as a smooth manifold - a manifold being intuitively something like a beach ball, donut or similar. Smooth means that when you look at a piece of the manifold at a sufficiently small scale, it looks more and more flat; it really is that simple, what makes it hard is when you introduce the technical tools you need to make precise calculations. So, since we don't actually know the size of the universe, perhaps what we can measure is that we are looking at a much smaller scale than we imagined.

But, some will say, how about the speed of light? The age of the universe is known, so if it started out in the big bang as a single point, it can only be a limited number of lightyears across, right? There are several things to say, that might rock that particular boat a little. Firstly, we don't know that the universe was just a single point in size - in fact, the way QM is interpreted, it seems reasonable to think it wasn't. Secondly, if inflation happened, the universe went through a phase when it expanded a lot faster than the speed of light. And thirdly, of course, the speed of light is only known to be the limit within what we know as vacuum in the space-time we observe now, it only limits how much of the universe we can see now; we have every reason to assume that there is a lot more of it than that.

95% is the number they always 'quote', for some reason - presumably because they know it sounds daft to say 'I don't know how much, but I'm sure it's a lot'. Nice, round numbers like 95 don't often turn up as the result of a genuine investigation; real, statistical results are much more awkward, of course - for probabilitic reasons, actually: if you could potentially get any number between 0 and 100 as a result, with 2 decimals (which is quite common), then there are about 10000 possible outcomes, and any number would, on the outset, have a probability of just 10E-4 (this is where those who actually understand probability will come and correct me, no doubt).

Apart from that, he is actually right, although he underestimates the number: it should be 100%. All climate models are wrong, we know that. This is because we are dealing with science, where we make observations, construct a model to explain them, make predictions, find that we are not quite right, change the model, and so on. You can even make a joke about this: Scientists know their theories are not The Truth, and what do you call people that tell something that they know isn't true? Yes! All scientists are liars!! (OK, I didn't say it was a GOOD joke)

Meaning, they are too expensive and are able to look through the incompetence of managers. I suppose it is quite daunting for a mediocre manager to try to dominate a mature engineer, who doesn't fall for his bluster and can't be scared into submission.

Someone who wants sample the air in that location, perhaps? To get a statistically useful dataset, you have to sample from as many, diverse locations as possible, including some where you would expect the readings to be higher than in other places. Otherwise you would get biased data; they were looking for the true average value across the globe, not the least scary number. I'm sure there will be samples that were taken from locations poor in CO2 as well.

Absolutely; which reminds me of a piece of C code I saw years back, and which I haven't been able to find again - perhaps somebody here would happen to know it. If I remember, it was an algorithm to find the best approximation to a straight line in a bitmap, given the two end points. What I remember is that it featured a rather eye-watering construction of two overlapping switch statements (?) which was syntactically legal, but perhaps shouldn't have been. Anyway, if it rings a bell, please let me know :-)

Well, of course - it only counts how many occurences of a certain string you can find. An alternative interpretation could be that since people would have to know what beautiful code looks like in order to decide what ugly code looks like, there must be far more C programmers who know how to write good code. Which makes sense, I think; C is a language that allows the coder to make horrible mistakes, so in order to survive, you have to develop a coding style with strong discipline, which is what makes beautiful code.

That's because there isn't any; it is just yet another example of a string of idiots accumulating nonsense as they pass their lack of understanding on to each other. As far as I have been able to tell, the actual thing that is called an 'EM drive' is not some silly contraption cooked up by a spaced out hobbyist, but the product of scientific, if somewhat speculative, reasoning. There is something called the Casimir effect:

http://en.wikipedia.org/wiki/C...

The speculation is that something like the Casimir effect could be achieved, that would produce a thrust - see:

http://en.wikipedia.org/wiki/E...

It doesn't seem completely implausible, but it is too early to tell. However, we are clearly not talking about 'reactionless propulsion' or 'warp drive', if it works, then it is a system that uses virtual particles as reaction mass, if you will. Virtual here doesn't mean 'unreal', BTW - these are real particles in the sense that they explain observable phenomena.

As far as I can see, Roger Shawyer is not a wild-eyed madman, but a serious engineer, who argues his case soberly. That is not to say that his claims are correct, but simply means that he actually offers something that is worth scientific scrutiny and which can be discussed and tested. On the other hand, since this is not all over the new channels, it is not something that has been demonstrated unambiguously enough yet; if this was definitely proven, then we would hear about it even in the general press.

There are two wikipedia articles:

http://en.wikipedia.org/wiki/E...
http://en.wikipedia.org/wiki/Q...

- that seem relatively trustworthy. To me it looks like a slightly speculative concept, but one that could well have some theoretical support; I am not an expert in QM, but to my eyes it looks somewhat plausible. He doesn't claim to violate fundamental laws of physics - if he is right, and this drive works, then it uses the same phenomenon that lies behind the Casimir effect (well, read the articles, really). It doesn't generate energy from nothing, energy is expended in the process; and it doesn't work like a rocket, it seems, but like a paddle steamer, in that it sort of crawls along in the soup of quantum fluctuations (yes, I don't know what actually means either, but it sounds cool, and apparently it is an observed phenomenon, ie. real).

Or indeed anything with a bit of meat on, if you're hungry.

It is obvious that you find it all too easy to sneer, but the big point he is making, as far as I can see, is that a serious lot can be achieved with relatively simply means, if you have the necessary insight and a bit of creativity. Nowadays too many people are blikered into thinking that we can only ever do anything at all with high technology; one of my favourite examples of the idiocy of this sort of viewpoint comes from the simple act of shaving. Not long ago people would use a straight razor - basically a knife with a core of high-carbon steel that could keep a sharp edge. You would probably only ever buy one in your life, and you could pass it down to your son for generations. Now, however, people are sold the idea that you need a contraption with 5 very thin platinum coated blades, which you can use only a few times, and which costs something like, what, $25 for a packet of 5? Something ridiculouos, any way. And the amazing thing is - the result is not actually better, you are just being taken for a ride.

So, back to this issue: this is not about your local hospital saving money, although thigh maight well benefit as well; this is about helping poor nations achieve a better standard of health without having hundreds of billions to splurge out on luxury equipment. And who knows, it might end up saving you money on the tax or insurance bill, if your health service gets a lot cheaper. Isn't that worth doing?

Is that what being 'a maker' means? Who would have thought it. So it is all about spending a load on high-tech equipment and the pushing a button?

I may just be a sad, old hippie, but I think relying on heavily computerized equipment, where you can download a blueprint, push a button and out comes a finished product, that doesn't mean you're a 'maker' in my book. Yes, I know I exaggerate, but still. Or is 'maker' what you call yourself when you don't want to learn how to actually do things, you just want the finished result?

Whatever - rant's over - but I think there is a lot of real benefit to learn how to do it the primitive way, even if you later just use a machine; it gives you an insight, just like being able to write a program well in C or assembler gives you a good ballast, even if you later only write Python programs. It is sometimes quite surprising how little difference there is between using an electric tool and a manual one, if you are competent with the techniques. Just take the process of cutting a piece of plywood: it seems enticingly easy to just take an electric jigsaw and the result is guaranteed to be good, right? Except that it amazingly easy to produce a poor result. Then try the same with a handsaw - it is somewhat slower and it may be physically harder work, but it is not actually that much harder or slower, and it is in fact quite easy to do it well, if you don't try to rush it.

What I'm getting at is, don't just fall for the fallacy thinking that the only way is to set up a high-tech production facility. A very large part of the advantage of machinery is that you can produce high volumes of the same thing, but it also introduces a limitation in flexibility and will hamper your creativity. And it easily insulates you from the basic insight into what you are doing - it makes you feel helpless without your machinery.