You must be joking. Why on earth would you use a complicated OS like Linux for something that just has to do one very particular job? And then have some hacker take control of it because they found a vulnerability in one of the services the probe was never intended to use anyway? Or the software crash because of some mysterious bug in some library written by some guy in his parents' basement 10 years ago?
I remember video players (tapes, early discs) that would start playing pretty much immediately after you switched them on. Nowadays, you switch on a DVD/blueray player and you get "Welcome" for about 20 seconds. Then the thing crashes every now and then so it needs a reboot. Yep, it's running some flavor of Linux. If you need reliability and efficiency, I'll take 70's technology any time.
Just program the thing directly for whatever it needs to do, using proprietary code. The code will be 1% the size and a lot more efficient.
(Not that I don't like Linux, by the way. It's great for general purpose equipment where you might actually need all of those capabilities)
That's not really a proof of determinism, but I know what you mean. Just by moving forward and backward a bit, I can make, say, the Andromeda nebula go back and forth in time by a few hours. A local civilisation may have just decided to invade us, but then go back in time to the point where the decision still has to be made. But obviously there can be no uncertainty about their future decision, since we already know what it is.
Only... we don't actually know what it is. All we can say is that the decision might or might not have been taken depending on what time coordinates we assign to the event, but we'll still have to wait for their signals to get here at the speed of light before we could possibly know what the decision was/will be. So things are just as uncertain whether they have "happened" or not. And we cannot influence them in any way, so it's really meaningless to say whether they happened in the past or the future.
The solution, I think, is to forget about our old-fashioned notion of simultaneity. Our clock has nothing to do with their clock. Just because we happen to change our time coordinates, doesn't mean that something "happens" over there. All events just go their own way in their local part of the universe, independently, and interact at the speed of light. There's no "now", except locally. Events over there may be happening just as randomly as over here, and it's meaningless to think about whether they happened earlier or later. They will only influence us in the far future in either case, and by then the decision certainly will have been taken.
Detemininism means that, knowing the initial conditions, you would be able to predict the outcome. That only really works locally: you can predict what you will observe. You can't predict "something will happen over there" but you might predict "I will observe the fact that something will have happened over there".
The decision in the Andromeda nebula is made when the local events get to that point, and then repercussions from that event radiate outward at maximum the speed of light (which takes more or less time depending on the observer), until they reach us. The event doesn't physically have time coordinates, it just does its thing. We might assign it some present, future or past time coordinate but that doesn't change the flow of things. Things just happen, without any reference to anybody's clock, and the fabric of space-time will allow us to come into contact with that separate flow of events some time in the future. At no point is the flow of events really reversed.
Or in yet another way, every tiny particle has its own clock and those clocks have nothing do do with each other. They can interact when they happen to reach the same place, but are otherwise independent.
Not sure I'm making any sense, it seems somehow clear to me but I'm having trouble communicating it.
If you get caught with fake rolex watches or other contraband, you could get in trouble. So it all depends on weather ripped music could be considered to fall into this category. And where the line is. What if you have songs illegally downloaded from P2P networks? Would that be considered contraband? If that's illegal, how do you prove your music came from an actual CD you own? It's the same kind of mp3/aac file.
Anyway, my personal suspicion is that they'll only give you trouble if they have some other "real" reason to give you trouble. If they had to arrest all tourists who have music on their laptops, they would have a lot of work on their hands.
But if you're not sure and want to play it 100% safe, save all your music on some cloud or other server, wipe it off your hard disk, then download it once you're in the US.
You are quite right. Light, or anything else in the universe, indeed doesn't care what coordinate system we use. The end result will still be the same, you can't calculate with one reference system that we will see something while another system says we won't. Or that two things will hit each other in one system and not in the other. But for things that are not directly observable, or vague numbers that don't physically mean anything ("How far is it? When did it get there? Does it even exist if we will never see it?"), you'll get wildly different answers. And you can't even say that one system is better than the other. Coordinate systems are just (flawed) tools for us to try and calculate things. It's all in our head, really. Physics doesn't care.
I think it's useful, though, to realise what's really happening, and where this "cosmic conveyor belt" is coming from. Many people seem to think that it's some kind of aether, influencing the speed of light. But it's really just us using math to undo the funky effects of relativity and, surprise, creating contradications with special relativity in the process. Which we then explain by assigning properties to "space itself". The day I figured that out, it was quite an epiphany for me.
There are other places where different metrics are being used: black holes, for example. That's another area where you can't really pick one true coordinate system. In fact, you might even say black holes don't exist and never will, because local time slows down to an asymptotic standstill before the last drop of matter falls in to complete the black hole. All we have is near-black-holes. But switch to a different coordinate system and there they are. They do exist after all, "right now". And then there's a choice of different metrics to describe the inside of them, the Schwarzschild metric being the most well-known but certainly not the only one. Time can stop, go backward, go imaginary, you name it. It's just us forcing physics into a badly fitting mathematical suit.
Over what distance were those measurements made? Probably many, many meters while the slight variations from the average would probably only occur on the scale of nanometers. No contradiction there. (Although it remains to be seen whether it's true).
But what you say about friction: why would this friction be greater if the observer happens to be going in the opposite direction? Why would two different observers, measuring the same beam of light while themselves having different speeds, measure different amounts of friction working on that light beam, resulting in a measurement of exactly the same speed relative to their moving selves? That just wouldn't make sense. In relativity, the speed of light is tied to the structure of space-time itself, it's simply a maximum speed, not just for light, but also for gravity (is that affected by this friction as well, to exactly the same degree as well?!) and anything else.
Faster than light expansion is just a mathematical oddity caused by the use of a particular coordinate system. Not that there's anything wrong with it, just that nobody ever seems to explain it properly.
Local distances and times are easy to measure objectively using clocks and measuring rods, but the definition is not so clear and unambiguous anymore when you're talking about large distances in the expanding universe. Different metrics exist, defining distances, times and speeds in a different way, yielding wildly different values while giving the same tangible results for any actual event. I will give you two ways of looking at the universe: the first conserves the speed of light but looks very weird, while the other looks more normal but does not respect Special Relativity. Under General Relativity, which allows a wider range of metrics, both models are perfectly valid and consistent. I will disregard the effects of gravity, but otherwise it should be a pretty accurate description, certainly enough to explain what "space itself" really means.
If you define distances, times and speeds using the common sense definitions from Special Relativity (using beams of light to measure distances, always assuming a constant speed of light), distant galaxies are traveling away from us at high speeds (but less than the speed of light) and therefore time passes more slowly for them. Since this has been the case ever since the big bang, they are younger than us at this point in time. They don't just look younger because we had to wait for their light to get here, but they really are younger "right now" even if we take the traveling time of light into account. If we could "look" at them directly without having to wait for the light to get here, like we could do in a mathematical model, we would "see" the universe getting younger and younger, and clocks ticking ever more slowly, the further out we "look" in our expanding universe. At a distance of c times the age of the universe, the big bang is happening "right now". This gives the universe a finite size (assuming nothing existed before the big bang) but it does contain an infinite amount of matter thanks to Lorentz contraction. Everything near the boundary is squished in the direction of the expansion so that an infinite amount of stuff fits in this finite amount of space.
This metric is a bit cumbersome because it gives us a special position at the center of the universe while in fact there's nothing special about our position at all. Some other, distant civilisation (in the distant future according to the above metric) will actually say that we don't exist yet and our galaxy is much younger than theirs, "now". (Using their definition of "now"). That's just the classic twin paradox, nothing really wrong with that, but it does make our point of view a bit subjective.
So cosmologists came up with a better metric, the cosmological model: they define time as whatever is measured by local clocks that are traveling at the same speed as the average galaxy in that area (the expansion speed vector), undoing time dilation due to the expansion and thereby making the whole universe the same age. Local distances are defined in such a way that objects look pretty much the same size everywhere (no Lorentz contraction due to expansion speed), which can be achieved by defining distances in function of a constant speed of light relative to the expanding universe. So in effect we stretched the universe and sped it up, just by using a different definition of "now" and by measuring distances differently. With this model, the universe looks nicely homogenous and truly infinite, making many calculations a lot easier. There's no longer anything special about our location.
But because we changed our definitions of space and time, some of the old assumptions from special relativity are no longer valid. Things can and do fly away from us at speeds well in excess of the speed of light simply because we are defining their speed differently. But the light from those places will ne
Wouldn't that disagree with the fact that the measured speed of light in vacuum, by any observer traveling at any speed, is the same? If the speed of light is just a matter of light being slowed down by virtual particles, there's no reason why your own speed wouldn't be added to or subtracted from the speed of a particular beam of light. Relativity would just go right out the window, we're back to aether theory.
Telenet is not DSL but coax cable (using the cable that used to be used only for TV). Capacity does go down if lots of people in the neighbourhood use it at the same time, but it doesn't matter whether they are using my modem (on the public channel) or someone else's. At least not according to Telenet. So they're not using "my" capacity, but obviously it can have an effect on the capacity of the local part of the network.
No, it's a separate channel so it's about the same effect whether they're using my base station or my neighbour's, it only affects the "big pipe" to our neighbourhood.
The commission is paid from other traders' transaction fees. You pay to trade, they get paid to trade. Unless the rules changed, I definitely remember day traders being able to buy and sell at the same price and end up with a profit back in the dot com craze.
The discounts are quite often more than 100%, they can actually buy a stock, sell it at the same price, and make money. Guess where that money is coming from...
I tried it for a little while, but basically gave up when I realized how many of my buys ended up looking like a little mark hovering slightly above a peak on the daily graph, and how many sells looked like a little mark just below the bottom. You had to zoom in to see the actual point on the graph where I made the transaction. I certainly seemed to have a knack for timing, it was quite incredible. I tried reversing my buying/selling decisions, but on those occasions I turned out to suddenly have perfect prediction capabilities (if I hadn't reversed them). Go figure.
I still have this nagging feeling that I should be able to beat those robots at their own game, the price swings do suggest it should be possible, but I became just humble enough to stop trying.
Money doesn't get created out of thin air. If HFT firms are making money, other investors are losing exactly that money. For example, patient investors who have put a limit order in and are waiting for someone to take it. They'll be consistently below the "improved" price and their order never gets executed.
No matter how you try to explain it, the HFT profits are coming from other investors' pockets, the stock market is not magic.
HFT improves liquidity? That sure explains all the mini-meltdowns we've seen recently. Very liquid indeed.
And when a stock starts going down, the difference in liquidity is a spread of 20.01 - 20.02 instead of 20.01 - 20.1. Don't expect to sell at a better price thanks to HFT algos. And when a stock goes up, it's the other way around obviously. These algos make money for their owners and that's their only purpose.
Same thing in Belgium with Telenet. Works quite well. You can close the extra channel if you want, but then they also revoke your access to other people's base stations. You only get access if you also provide access yourself. Which doesn't cost you anything except maybe a tiny bit of electricity.
So Apple was helping booksellers keep Amazon from getting a monopoly, and this is considered collusion? I'm starting to understand why Apple is fighting this rather than settling.
I understand what Apple wanted to do, a 30% profit margin on books is certainly a great deal, but why did the publishers care about Amazon's 5% profit margin? Why would they rather have 70% of $10 instead of getting $7 from Amazon and letting Amazon sell those books for whatever price they wanted? OMG Amazon bought my book for $7 and then sold it for $3, the bastards! How dare they lose money on my book! They're selling them by the thousands and giving me $7 for each one!
Of course, once the contract with Apple was in place, with the Most Favorite Nation clause in it, that provided a very strong incentive for publishers to force Amazon to change their model, making loss-making sales impossible. But I still don't see what the publishers initially had to gain by signing with Apple. Want more money for your book? Just increase the wholesale price! Who cares what Amazon sells it for afterwards?
So any store that advertises "guaranteed lowest price" and offers to lower its price if you can find the same product cheaper elsewhere, is colluding to increase prices?
But why would anyone care if Amazon was selling their books for $3? They are still getting the same wholesale price, right? If someone bought tons of copies of my products for a reasonable price and then sold them to loads of people for much less, eating the loss themselves, I couldn't be happier!
Of course it becomes a problem once Apple adds the "most favored nation" clause, because Apple would then start selling the books at the same ridiculously low price and give the publishers a slice of that lower price instead of their normal fee, but the argument existed before that. Jobs actually convinced the publishers to join his model because they were fed up with Amazon offering their books for ridiculous prices. Why? Amazon was eating the loss, not the publishers. Every book sold at those low prices gave the publishers their full wholesale price.
I did disregard gravity since the density of the universe is pretty low on a large scale, so maybe there are some corrections to be made to take the (small) curvature of the universe due to gravity into account, but I think most of my explanation is still valid. If you can just imagine a universe without (much) gravity, I don't think there's anything wrong with the models I described. I will just give them again with a bit more detail:
The first reference system I proposed is an extremely simple one (but with complicated consequences) constructed along the lines of special relativity:
1. Pick some "stationary" point in our vicinity as the origin (of course not the earth or the sun, since they are revolving around the center of our galaxy, but some point in our local cluster of galaxies should do fine). 2. Using a set of standard "measuring rods" (just like Einstein used in his popular description of relativity), which are placed stationary to the origin of the reference frame, construct three perpendicular axes to assign space coordinates. 3. Place a clock at the origin which sends out a signal every second. Clocks are also placed at various other places in the universe and synchronised by listening to the origin clock and applying a correction of distance divided by light speed. A clock located one light second away, for example, would add one second to the received time to indicate current time in our reference frame. All these clocks are stationary in our reference frame, they are not moving with the expansion of the universe.
In this reference system, distant galaxies are flying away from us at high speed and are therefore subject to lorentz contraction and time dilation. They will appear shrunk in the direction of motion, and will age more slowly. They are also closer together because the space between them is lorentz-contracted as well. Obviously, an alien civilisation in those galaxies would consider themselves to be the center, and would say we are aging more slowly than them, but that's just the classic twin paradox and no contradiction. We are free to use our own reference system.
Anyway, using this reference frame, objects at large distances are younger because they have been aging more slowly ever since the big bang. At some distance away from us, objects are traveling at speeds close to c and they are so young that the big bang has only just happened for them. A little bit further, at c times the age of the universe, there's a singularity where the big bang is happening now.
Of course I realise that this is a strange way of looking at the universe, but it obeys the principles of special relativity (disregarding gravity) and therefore has the property that nothing exceeds the speed of light relative to the origin.
The cosmological model, which is a lot more practical to use, is constructed in a different way. Clocks at any point in the universe are set so they indicate the amount of time passed since the big bang as experienced by a local observer that is moving with the expansion of the universe, and distances are measured so that local light speed, relative to a local observer moving with the expansion (i.e. relative to "expanding space"), is c. Now the universe is the same age everywhere, looks the same everywhere (no more lorentz contraction from the expansion), but we gave up the property of nothing being able to go faster than light globally. Local light speed is c relative to local observers who are moving away from us, or in other words, relative to "expanding space". But those observers can fly away from us at speeds well in excess of c.
Well, I'm not going to argue about the exact definition of c, but I certainly meant the fixed mathematical value. The silly example just tried to show how it is possible for things to go faster than c without causing any problems with relativity. If you choose a coordinate system that is not consistent with the definitions used in Special Relativity, then yes, you will find speeds greater than 3 x 10^8 m/s. This can be very useful, as is the case with the cosmological model (which, unlike my silly example, does preserve "local" speed of light but not global speed of light throughout the universe).
My silly example served no purpose other than to make the point that speeds are just something measured in some coordinate system and therefore the choice of coordinates can change the values. The notion of a galaxy moving away from us at some specific speed only has meaning if we also describe the reference system being used.
If we are using the cosmological model, it is perfectly normal for galaxies to be flying away from us at many times c. With a different set of coordinates, obeying the definitions of Special Relativity, we will only find speeds lower than c but the universe will look distorted because of lorentz contraction and time dilation. Which is why pretty much anyone uses the cosmological model and explains the resulting high speeds as "space itself expanding".
Slashdot Mirror
You must be joking. Why on earth would you use a complicated OS like Linux for something that just has to do one very particular job? And then have some hacker take control of it because they found a vulnerability in one of the services the probe was never intended to use anyway? Or the software crash because of some mysterious bug in some library written by some guy in his parents' basement 10 years ago?
I remember video players (tapes, early discs) that would start playing pretty much immediately after you switched them on. Nowadays, you switch on a DVD/blueray player and you get "Welcome" for about 20 seconds. Then the thing crashes every now and then so it needs a reboot. Yep, it's running some flavor of Linux. If you need reliability and efficiency, I'll take 70's technology any time.
Just program the thing directly for whatever it needs to do, using proprietary code. The code will be 1% the size and a lot more efficient.
(Not that I don't like Linux, by the way. It's great for general purpose equipment where you might actually need all of those capabilities)
That's not really a proof of determinism, but I know what you mean. Just by moving forward and backward a bit, I can make, say, the Andromeda nebula go back and forth in time by a few hours. A local civilisation may have just decided to invade us, but then go back in time to the point where the decision still has to be made. But obviously there can be no uncertainty about their future decision, since we already know what it is.
Only... we don't actually know what it is. All we can say is that the decision might or might not have been taken depending on what time coordinates we assign to the event, but we'll still have to wait for their signals to get here at the speed of light before we could possibly know what the decision was/will be. So things are just as uncertain whether they have "happened" or not. And we cannot influence them in any way, so it's really meaningless to say whether they happened in the past or the future.
The solution, I think, is to forget about our old-fashioned notion of simultaneity. Our clock has nothing to do with their clock. Just because we happen to change our time coordinates, doesn't mean that something "happens" over there. All events just go their own way in their local part of the universe, independently, and interact at the speed of light. There's no "now", except locally. Events over there may be happening just as randomly as over here, and it's meaningless to think about whether they happened earlier or later. They will only influence us in the far future in either case, and by then the decision certainly will have been taken.
Detemininism means that, knowing the initial conditions, you would be able to predict the outcome. That only really works locally: you can predict what you will observe. You can't predict "something will happen over there" but you might predict "I will observe the fact that something will have happened over there".
The decision in the Andromeda nebula is made when the local events get to that point, and then repercussions from that event radiate outward at maximum the speed of light (which takes more or less time depending on the observer), until they reach us. The event doesn't physically have time coordinates, it just does its thing. We might assign it some present, future or past time coordinate but that doesn't change the flow of things. Things just happen, without any reference to anybody's clock, and the fabric of space-time will allow us to come into contact with that separate flow of events some time in the future. At no point is the flow of events really reversed.
Or in yet another way, every tiny particle has its own clock and those clocks have nothing do do with each other. They can interact when they happen to reach the same place, but are otherwise independent.
Not sure I'm making any sense, it seems somehow clear to me but I'm having trouble communicating it.
If you get caught with fake rolex watches or other contraband, you could get in trouble. So it all depends on weather ripped music could be considered to fall into this category. And where the line is. What if you have songs illegally downloaded from P2P networks? Would that be considered contraband? If that's illegal, how do you prove your music came from an actual CD you own? It's the same kind of mp3/aac file.
Anyway, my personal suspicion is that they'll only give you trouble if they have some other "real" reason to give you trouble. If they had to arrest all tourists who have music on their laptops, they would have a lot of work on their hands.
But if you're not sure and want to play it 100% safe, save all your music on some cloud or other server, wipe it off your hard disk, then download it once you're in the US.
You are quite right. Light, or anything else in the universe, indeed doesn't care what coordinate system we use. The end result will still be the same, you can't calculate with one reference system that we will see something while another system says we won't. Or that two things will hit each other in one system and not in the other. But for things that are not directly observable, or vague numbers that don't physically mean anything ("How far is it? When did it get there? Does it even exist if we will never see it?"), you'll get wildly different answers. And you can't even say that one system is better than the other. Coordinate systems are just (flawed) tools for us to try and calculate things. It's all in our head, really. Physics doesn't care.
I think it's useful, though, to realise what's really happening, and where this "cosmic conveyor belt" is coming from. Many people seem to think that it's some kind of aether, influencing the speed of light. But it's really just us using math to undo the funky effects of relativity and, surprise, creating contradications with special relativity in the process. Which we then explain by assigning properties to "space itself". The day I figured that out, it was quite an epiphany for me.
There are other places where different metrics are being used: black holes, for example. That's another area where you can't really pick one true coordinate system. In fact, you might even say black holes don't exist and never will, because local time slows down to an asymptotic standstill before the last drop of matter falls in to complete the black hole. All we have is near-black-holes. But switch to a different coordinate system and there they are. They do exist after all, "right now". And then there's a choice of different metrics to describe the inside of them, the Schwarzschild metric being the most well-known but certainly not the only one. Time can stop, go backward, go imaginary, you name it. It's just us forcing physics into a badly fitting mathematical suit.
Over what distance were those measurements made? Probably many, many meters while the slight variations from the average would probably only occur on the scale of nanometers. No contradiction there. (Although it remains to be seen whether it's true).
But what you say about friction: why would this friction be greater if the observer happens to be going in the opposite direction? Why would two different observers, measuring the same beam of light while themselves having different speeds, measure different amounts of friction working on that light beam, resulting in a measurement of exactly the same speed relative to their moving selves? That just wouldn't make sense. In relativity, the speed of light is tied to the structure of space-time itself, it's simply a maximum speed, not just for light, but also for gravity (is that affected by this friction as well, to exactly the same degree as well?!) and anything else.
Faster than light expansion is just a mathematical oddity caused by the use of a particular coordinate system. Not that there's anything wrong with it, just that nobody ever seems to explain it properly.
Local distances and times are easy to measure objectively using clocks and measuring rods, but the definition is not so clear and unambiguous anymore when you're talking about large distances in the expanding universe. Different metrics exist, defining distances, times and speeds in a different way, yielding wildly different values while giving the same tangible results for any actual event. I will give you two ways of looking at the universe: the first conserves the speed of light but looks very weird, while the other looks more normal but does not respect Special Relativity. Under General Relativity, which allows a wider range of metrics, both models are perfectly valid and consistent. I will disregard the effects of gravity, but otherwise it should be a pretty accurate description, certainly enough to explain what "space itself" really means.
If you define distances, times and speeds using the common sense definitions from Special Relativity (using beams of light to measure distances, always assuming a constant speed of light), distant galaxies are traveling away from us at high speeds (but less than the speed of light) and therefore time passes more slowly for them. Since this has been the case ever since the big bang, they are younger than us at this point in time. They don't just look younger because we had to wait for their light to get here, but they really are younger "right now" even if we take the traveling time of light into account. If we could "look" at them directly without having to wait for the light to get here, like we could do in a mathematical model, we would "see" the universe getting younger and younger, and clocks ticking ever more slowly, the further out we "look" in our expanding universe. At a distance of c times the age of the universe, the big bang is happening "right now". This gives the universe a finite size (assuming nothing existed before the big bang) but it does contain an infinite amount of matter thanks to Lorentz contraction. Everything near the boundary is squished in the direction of the expansion so that an infinite amount of stuff fits in this finite amount of space.
This metric is a bit cumbersome because it gives us a special position at the center of the universe while in fact there's nothing special about our position at all. Some other, distant civilisation (in the distant future according to the above metric) will actually say that we don't exist yet and our galaxy is much younger than theirs, "now". (Using their definition of "now"). That's just the classic twin paradox, nothing really wrong with that, but it does make our point of view a bit subjective.
So cosmologists came up with a better metric, the cosmological model: they define time as whatever is measured by local clocks that are traveling at the same speed as the average galaxy in that area (the expansion speed vector), undoing time dilation due to the expansion and thereby making the whole universe the same age. Local distances are defined in such a way that objects look pretty much the same size everywhere (no Lorentz contraction due to expansion speed), which can be achieved by defining distances in function of a constant speed of light relative to the expanding universe. So in effect we stretched the universe and sped it up, just by using a different definition of "now" and by measuring distances differently. With this model, the universe looks nicely homogenous and truly infinite, making many calculations a lot easier. There's no longer anything special about our location.
But because we changed our definitions of space and time, some of the old assumptions from special relativity are no longer valid. Things can and do fly away from us at speeds well in excess of the speed of light simply because we are defining their speed differently. But the light from those places will ne
Wouldn't that disagree with the fact that the measured speed of light in vacuum, by any observer traveling at any speed, is the same? If the speed of light is just a matter of light being slowed down by virtual particles, there's no reason why your own speed wouldn't be added to or subtracted from the speed of a particular beam of light. Relativity would just go right out the window, we're back to aether theory.
we'll have plenty of time to figure out how to get off our planet in the next million years or so.
Famous last words.
Telenet is not DSL but coax cable (using the cable that used to be used only for TV). Capacity does go down if lots of people in the neighbourhood use it at the same time, but it doesn't matter whether they are using my modem (on the public channel) or someone else's. At least not according to Telenet. So they're not using "my" capacity, but obviously it can have an effect on the capacity of the local part of the network.
No, it's a separate channel so it's about the same effect whether they're using my base station or my neighbour's, it only affects the "big pipe" to our neighbourhood.
The commission is paid from other traders' transaction fees. You pay to trade, they get paid to trade. Unless the rules changed, I definitely remember day traders being able to buy and sell at the same price and end up with a profit back in the dot com craze.
Except if the HFT firms get paid a commission per transaction which is higher than the tax. Guess who ends up really paying the tax.
The discounts are quite often more than 100%, they can actually buy a stock, sell it at the same price, and make money. Guess where that money is coming from...
I tried it for a little while, but basically gave up when I realized how many of my buys ended up looking like a little mark hovering slightly above a peak on the daily graph, and how many sells looked like a little mark just below the bottom. You had to zoom in to see the actual point on the graph where I made the transaction. I certainly seemed to have a knack for timing, it was quite incredible. I tried reversing my buying/selling decisions, but on those occasions I turned out to suddenly have perfect prediction capabilities (if I hadn't reversed them). Go figure.
I still have this nagging feeling that I should be able to beat those robots at their own game, the price swings do suggest it should be possible, but I became just humble enough to stop trying.
I then went on to sell it for another $10 more. Just a few more trades like that, and I'll have enough money to buy a gold plated bidet.
Money doesn't get created out of thin air. If HFT firms are making money, other investors are losing exactly that money. For example, patient investors who have put a limit order in and are waiting for someone to take it. They'll be consistently below the "improved" price and their order never gets executed.
No matter how you try to explain it, the HFT profits are coming from other investors' pockets, the stock market is not magic.
HFT improves liquidity? That sure explains all the mini-meltdowns we've seen recently. Very liquid indeed.
And when a stock starts going down, the difference in liquidity is a spread of 20.01 - 20.02 instead of 20.01 - 20.1. Don't expect to sell at a better price thanks to HFT algos. And when a stock goes up, it's the other way around obviously. These algos make money for their owners and that's their only purpose.
Same thing in Belgium with Telenet. Works quite well. You can close the extra channel if you want, but then they also revoke your access to other people's base stations. You only get access if you also provide access yourself. Which doesn't cost you anything except maybe a tiny bit of electricity.
So Apple was helping booksellers keep Amazon from getting a monopoly, and this is considered collusion? I'm starting to understand why Apple is fighting this rather than settling.
I understand what Apple wanted to do, a 30% profit margin on books is certainly a great deal, but why did the publishers care about Amazon's 5% profit margin? Why would they rather have 70% of $10 instead of getting $7 from Amazon and letting Amazon sell those books for whatever price they wanted? OMG Amazon bought my book for $7 and then sold it for $3, the bastards! How dare they lose money on my book! They're selling them by the thousands and giving me $7 for each one!
Of course, once the contract with Apple was in place, with the Most Favorite Nation clause in it, that provided a very strong incentive for publishers to force Amazon to change their model, making loss-making sales impossible. But I still don't see what the publishers initially had to gain by signing with Apple. Want more money for your book? Just increase the wholesale price! Who cares what Amazon sells it for afterwards?
So any store that advertises "guaranteed lowest price" and offers to lower its price if you can find the same product cheaper elsewhere, is colluding to increase prices?
But why would anyone care if Amazon was selling their books for $3? They are still getting the same wholesale price, right? If someone bought tons of copies of my products for a reasonable price and then sold them to loads of people for much less, eating the loss themselves, I couldn't be happier!
Of course it becomes a problem once Apple adds the "most favored nation" clause, because Apple would then start selling the books at the same ridiculously low price and give the publishers a slice of that lower price instead of their normal fee, but the argument existed before that. Jobs actually convinced the publishers to join his model because they were fed up with Amazon offering their books for ridiculous prices. Why? Amazon was eating the loss, not the publishers. Every book sold at those low prices gave the publishers their full wholesale price.
Wait a minute... Is whale hunting considered to be a good thing nowadays? It's so hard to keep up.
A campaign promoting the many benefits of child pornography? With about 5000 tonnes of magazines sitting unwanted in warehouses...
I did disregard gravity since the density of the universe is pretty low on a large scale, so maybe there are some corrections to be made to take the (small) curvature of the universe due to gravity into account, but I think most of my explanation is still valid. If you can just imagine a universe without (much) gravity, I don't think there's anything wrong with the models I described. I will just give them again with a bit more detail:
The first reference system I proposed is an extremely simple one (but with complicated consequences) constructed along the lines of special relativity:
1. Pick some "stationary" point in our vicinity as the origin (of course not the earth or the sun, since they are revolving around the center of our galaxy, but some point in our local cluster of galaxies should do fine).
2. Using a set of standard "measuring rods" (just like Einstein used in his popular description of relativity), which are placed stationary to the origin of the reference frame, construct three perpendicular axes to assign space coordinates.
3. Place a clock at the origin which sends out a signal every second. Clocks are also placed at various other places in the universe and synchronised by listening to the origin clock and applying a correction of distance divided by light speed. A clock located one light second away, for example, would add one second to the received time to indicate current time in our reference frame. All these clocks are stationary in our reference frame, they are not moving with the expansion of the universe.
In this reference system, distant galaxies are flying away from us at high speed and are therefore subject to lorentz contraction and time dilation. They will appear shrunk in the direction of motion, and will age more slowly. They are also closer together because the space between them is lorentz-contracted as well. Obviously, an alien civilisation in those galaxies would consider themselves to be the center, and would say we are aging more slowly than them, but that's just the classic twin paradox and no contradiction. We are free to use our own reference system.
Anyway, using this reference frame, objects at large distances are younger because they have been aging more slowly ever since the big bang. At some distance away from us, objects are traveling at speeds close to c and they are so young that the big bang has only just happened for them. A little bit further, at c times the age of the universe, there's a singularity where the big bang is happening now.
Of course I realise that this is a strange way of looking at the universe, but it obeys the principles of special relativity (disregarding gravity) and therefore has the property that nothing exceeds the speed of light relative to the origin.
The cosmological model, which is a lot more practical to use, is constructed in a different way. Clocks at any point in the universe are set so they indicate the amount of time passed since the big bang as experienced by a local observer that is moving with the expansion of the universe, and distances are measured so that local light speed, relative to a local observer moving with the expansion (i.e. relative to "expanding space"), is c. Now the universe is the same age everywhere, looks the same everywhere (no more lorentz contraction from the expansion), but we gave up the property of nothing being able to go faster than light globally. Local light speed is c relative to local observers who are moving away from us, or in other words, relative to "expanding space". But those observers can fly away from us at speeds well in excess of c.
Am I making slightly more sense now?
Well, I'm not going to argue about the exact definition of c, but I certainly meant the fixed mathematical value. The silly example just tried to show how it is possible for things to go faster than c without causing any problems with relativity. If you choose a coordinate system that is not consistent with the definitions used in Special Relativity, then yes, you will find speeds greater than 3 x 10^8 m/s. This can be very useful, as is the case with the cosmological model (which, unlike my silly example, does preserve "local" speed of light but not global speed of light throughout the universe).
My silly example served no purpose other than to make the point that speeds are just something measured in some coordinate system and therefore the choice of coordinates can change the values. The notion of a galaxy moving away from us at some specific speed only has meaning if we also describe the reference system being used.
If we are using the cosmological model, it is perfectly normal for galaxies to be flying away from us at many times c. With a different set of coordinates, obeying the definitions of Special Relativity, we will only find speeds lower than c but the universe will look distorted because of lorentz contraction and time dilation. Which is why pretty much anyone uses the cosmological model and explains the resulting high speeds as "space itself expanding".