Schrödinger's hat

If you could provide package names and reviews/overviews of what they do that'd be just peachy..

It would continue at the same velocity. When the propulsion stops, acceleration goes to 0. Acceleration measures how quickly velocity changes so time is a factor as well. If your propulsion was turned back on, acceleration would go back to it's previous value, so the speed (velocity) would start increasing again. You'd have to leave your engine on for the same amount of time it was on previously to double your speed. Play asteroids for a little while. Note that when you hold down the up key you are accelerating, when you release it you are not.

I just had this same (I think) question occur to me so rather than start a new thread I'll bump this one. Rephrasing in case the answer to my question differs: Is there any (and if so, how strong?) bias for the (approximate) plane of orbit/rotation of a solar system to lie along the plane of galactic rotation?

If it were neutrinos wouldn't we see wildly varying rates depending on things like sample size (for neutrino emitters), time of day (the earth absorbs at least a few neutrinos, although I am not sure how this compares to seasonal variation), and proximity to a nuclear reactor? The news article also makes it look like they based this (rather controversial) finding on a single event. Also I reached a dead end looking for links to the actual papers after here. Rather bad form for Stanford not naming the actual papers. Anyone have a link? Edit: Some more info: http://physicsworld.com/cws/article/news/36108 http://arxiv.org/abs/0808.3156

I'm by no means an expert, but what you are asking seems more in the realm of IT/computer security.. Although computer science is important for understanding and implementing cryptography, it is not quite as necessary for using it. In terms of where to start reading, I don't know of any specific books, but I can give you some names/things to google. Bruce Schneier is the first name that comes to mind when talking about security. I am given to understand he has written a large number of books/emails and given lectures. Many of these are quite accessible. PGP (Pretty good privacy) Is an encrypton/digital signing algorithm. Tor is one method of gaining some anonymity, although with fewer people controlling larger sections of the internet it has its flaws. Read a bit about cookies and other methods of tracking people as they browse, too. There was an article on slashdot recently about a do not track registry which had a number of good comments. These should give you a good starting point from which you can do further reading. One of the problems with keeping your information private is you have to convince those you share it with to keep it private, too. It's no use installing and using pgp if noone else uses it as you won't be able to encrypt anything for them to view, and they won't encrypt emails to you. Also, what do you mean by strong maths background? Unfortunately people have varying opinions of this and it becomes quite ambiguous.

I don't understand. There's a thought here somewhere about this making kinetic energy non-local. Also my intuition (hardly a reliable tool in these matters) says that the stress energy tensor being on the other side of the equation (and potentially 0) contradicts this somewhat. Would a (very) generalised v^2 be more appropriate? Is velocity still even a useful concept at this point?

Khan Academy is always a good place to start, looks like he approaches it both from a chemistry, and a physics point of view.

TonyMcC is right. Unless heat leaves the air somehow in the compressed stage it won't really cool. What do you want this for?

If you want to talk purely in terms of number of parts (again, not safe or comfortable) I'd go electric. Have a homopolar or simple DC motor direct drive to, or part of the rear axle (no diff/gearbox). A battery a switch to turn it on maybe a variable resistor to reduce the shock as you start moving (what luxury) a chassis a single front wheel with handlebar steering

Tidal and other wave effects aside, the surface of the water should be a surface of constant potential in the (rotating) frame of the surface of the planet. So if you had, say, a planet sized cylindrical object then the water would form a roughly cylindrical ocean (it would bulge in the middle somewhat as gravity there would be much stronger). The ocean surface would be fairly smooth the whole way so other than the horizon looking more curved in one direction than the other you wouldn't really be able to tell (unless the planet was very small/dense). The faster the object rotates the more stretched the ocean will be in that direction.

This should probably be in speculations as we can't even make a billionth of a nanogram of antimatter. It all depends on how much fuel you take with you, Antimatter is a dense enough fuel that very high gamma (0.99c or so) could be achieved if enough could be produced. However things would start becoming prohibitive above about 0.9c as the fuel required would scale (at best linearly) with gamma or [math]\frac{1}{\sqrt{1-\frac{v^2}{c^2}}}[/math] Looking at a plot (v=1 on this graph is the speed of light) of this can be instructive (see how quickly it increases as you get past v=0.9c).

First you need to go insane. To help with this goal I suggest you come hang out on the chat room.

The problem is not that you are undergoing an acceleration, it's that the acceleration is caused by forces on one part of your body (ie. your feet or your back). The way to overcome this would be to exert a homogeneous force on the body of the person being accelerated. Unfortunately the only such force we know of is gravitational, and there is no known way to manipulate gravitational fields without (large amounts of) mass. There is research into extremely strong magnetic fields (example) which could be relevant, although I doubt anything over a few g's (maybe 10s of gs?) of acceleration could be managed without ill effects (the human body is not homogeneous and the field will effect different parts of you by different amounts, if the field is too strong it could, for example, rupture all of your arteries by pulling too hard on the blood). Other staples of science fiction are acceleration beds or chairs where the person is surrounded in a big squishy cushion or a fluid. This acts to distribute the pressure evenly over the entire body (and in the case of the fluid will act as an extra-effective pressure suit, keeping your insides and blood from exploding out your anus). At any rate, our travels for any significant distance (intercontinental, interplanetary or further) will be limited by energy rather than acceleration for what looks to be a very long time -- the main reason rockets accelerate so quickly is to get out of the atmosphere where they waste a lot of energy to drag and to thrusting straight up (there's also a lot to do with energy efficiency deep in a gravitational well, but I digress) -- so a good old one or two gees should do us for most purposes, unless you really want your transatlantic train trip to take less than half an hour.

The flywheel will serve to smooth out the input, not really needed much as wind doesn't tend to vary over short time scales. Also your turbine should act as a bit of a flywheel on its own. I'd suggest removing it to begin with, and if you find your output changes rapidly, or your turbine stalls in a momentary lull in the wind then try it with the flywheel back on.

Well first we'd have to know what exactly it meant for there to be another universe, so far we've only been able to look at this one. Then we'd have to find out that wormholes did indeed exist. Then we'd have to find a way to link them to other universes (as far as I know the concept of a wormhole as taken anywhere near seriously by scientists only pertains to links between points in our spacetime). Then we'd have some idea of how to answer your question.

If you want your system to be responsive you're probably a lot better off spending your money on an SSD for your OS and programs volume (and then a HDD for bulk storage) than buying a high end CPU. Ram is a good idea too (16GB should be more than even the most bloaty programs use for a few years yet, for most purposes at least). <Shameless plug> Also picking the right software can make a huge difference. As an extreme example I installed a lightweight linux on my eee recently and it's far more responsive than many newer desktop machines with windows 7 i have used </shameless plug>

Uhmmm, careful what you mean by dimension. Spacial dimension != degree of freedom. What you appear to be doing is picking (sets of) degrees of freedom and calling them a dimension. I suppose this is a useful exercise in thinking about how the universe could be different but bear in mind it is not what physicists generally refer to as a dimension.

Even if it wasn't the answer I was looking for, it was quite interesting and I'm slightly disappointed that he stopped showing off. Also why is Xerxes talking about Xerxes in the third person?

Uhm, it depends on what you mean exactly. I've heard of transistors that will switch in the Terahertz range, but I believe they have many problems that make them unsuitable for the types of chips most general purpose computers use. I suppose if one were to get a very simple processor design from the 1980s, make it out of such transistors, cool it with liquid nitrogen (or helium if it does not undergo some kind of state change), then ramp the clock rate up until it stopped working. I would guess if one were to put a lot of money into such a project one could get something switching at 100s of GHz. It probably wouldn't be very worthwhile, I doubt such a processor would be very useful.

Post your working, makes it easiest to see where you went wrong. You can use [math]\text{[math]}[/math]and[/math] to enclose equations to make it a little easier to read, also \frac{upperstuff}{lowerstuff} will make a fraction

If the containers are in equilibrium somehow (ie. they are linked by a pipe, linked to the same hose, or you are only using one pump) then then 2 will be true as the flow will always be such that they are at equal pressure. Otherwise neither is necessarily true, the flow rate depends on the pressure difference, nozzle size and many factors. Tank 2 will fill up first, but will not take exactly double the time. Depending on exactly what you are trying to do there are some simple and not so simple ways to measure the mass of the air. Any direct mass measurement (ie. using scales or inertia) will be quite cumbersome, but it is not usually too hard to find out how many molecules of whichever compounds are in the tank, and multiply by molecular mass. Ie. look up or calculate N(T,P,V) somehow where N is number, T is temp, P is Pressure and V is volume. If you know the volume of the tanks and the pressure you are bringing them to then the simplest way is just to add a temperature monitor to something that is thermally connected to the inside (outside of a metal tank works great, preferably a bit away from the nozzle). You already have P, and I'm assuming V The simplest (not terribly accurate, but could probably do the job) model is ideal gas PV=NRT or N=PV/(RT), multiply by average molecular mass I encourage you to look up the exact percentages, but something along the lines of 78% N2 21%O2 1% other so 0.8*14grams/mol+0.2*16grams/mol=cbb finding a calculator) m=PV/RT*14 (in grams) If you need higher precision or help with figuring things out (should find a value for R on wiki, look up ideal gas law to get you started) don't hesitate to ask

Bear in mind that's not a very exact analogy as a tsunami is a wave-phenomenon, not a quantum phenomenon (wavefunction), but it has some use. I find the many worlds interpretation is useful in this regard, especially when considering an as of yet unobserved photon which has interacted with an electron. There is a device called a quantum eraser, I do not know if anyone has built one with the double slit experiment, but instead of talking about spin and things I'll use it as an example, the principle stands even if this experiment would be prohibitively difficult to perform. If one were to fire a photon at one slit during the double slit experiment, but not receive/measure it (including having it interact with any other system you interact with) the whole electron/slits/photon system is still in a superposition. Because of incompatible variables (Heisenberg's uncertainty principle etc) there will be a way that you can measure the photon which destroys the information about the electron -- I imagine a very precise measure of its momentum would work (this is the prohibitively difficult part, as it would be difficult to make this measurement without knowing where it was, this is why other such experiments tend to use spin entanglement). If you do this erasure of information while the electron is still in flight (ie. you haven't measured it yet) then the interference pattern will be seen even though you made a measurement (providing the results of that measurement don't exist anywhere in the universe) This is why I like to think of things in terms of many worlds, before the measurement you are equally in all the universes where the electron took every path. After you interact with the photon which interacted with the electron you have narrowed down the range of universes this instance of you is in to one of two sets The ones where it went left and the ones where it went right in this case it can't interfere so no pattern is produced

http://en.wikipedia.org/wiki/Nucleation http://aftermathmagazine.blogspot.com/2009/01/mentos-and-diet-coke-truth-revealed.html Can't really explain anything that's not on there, if you have trouble understanding something feel free to ask. Also other carbonated beverages do this, it just seems that diet coke works a bit better. I do not know exactly why this is, but I can make a couple of conjectures. Non-diet beverages contain a lot of sugar, this could reduce the amount of CO2 that can be dissolved in them (diet coke is fizzier, if you will) Something about the artificial sweetner/lack of sugar makes the froth that forms in the diet coke more stable (think suds/froth in soapy water vs pure water. A bottle of detergent in some rapids would make a real mess) this would mean that the CO2 being released would be more likely to force it out of the bottle rather than escaping around the sides.

Well?

Still reading, just don't have much to say. Thanks for the response (although I can barely follow what Xerxes is saying, last I did that kind of maths it was mostly rubbing objects and their properties together until I got what I wanted) Yes, I've started reading that recently, working through it as I get the time. Also some Stanford lectures I found, but they are sadly lacking in depth as it was merely an introduction for another course. What you've been saying agrees with my intuition so far, I guess the word curvature means a very different and/or incorrect thing as far as I was concerned. Perhaps the word I was looking for is, in fact, connection. ie. the way any vectors/tensors/things at one point are transformed by travelling to adjacent points in space-time. Random thought: A slight problem with this is the word adjacent -- the concept of adjacency seems predicated on the existence of the metric -- I think this concept of a more generalised and abstracted connection that Xerxes is getting at helps here (if I understand him correctly). Still trying to wrap my head around the idea of a reality based upon a disjoint set. This resonates in some ways with vague notions I have about entanglement, but that discussion is for much, much later. Having trouble comprehending this bit or possibly the paragraph above.