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Messages - David Cooper
1
« on: 21/05/2013 18:33:38 »
I would like to throw a thought into the ring to see if it is in any way new. To many, the idea of a cat being both alive and dead at the same time until it's observed by someone is a step too far, and this is because if a human observer is able to force a collapse of the wavefunction, a cat should really be able to do likewise. But what is it about us (and cats) that could drive this collapse? I reckon the answer is that both contain information systems, and trying to maintain highly complex information in multiple states may be more difficult than maintaining mountains of material in multiple states, so if the model in the brain is forced to simplify and take up a specific form, that would force the external reality to simplify too to remain compatible with the data. So, it isn't measurement that forces a collapse, but the integration of the resulting data into an information system which will then apply complex processing to it.
It may really be that when we look out into the universe through a telescope, we can potentially force whole uninhabited galaxies to throw off most of their possible states so that they can appear to us in a particular, specific form rather than a fuzzy mess of multiple possibilities. This would not result in any causality travelling back billions of years through time though, because it would only force that galaxy to take up a specific form now, while it's entire past history up to that point would remain fuzzy. The first complex observer to look at it would force a collapse, and that collapse would be transmitted throughout the universe in an instant such that no other observer could force an incompatible collapse of the wavefunction of the same object.
2
« on: 21/05/2013 18:20:24 »
The trouble with that is the part where the object moves faster than the speed of light. That isn't going to happen. But, there is gravitational lensing, which allows multiple images of a galaxy to be seen round the edges of a nearer galaxy which is directly in front of the other. Even then, all the distorted images of the further-away galaxy will be following roughly the same length of path. What we really need is a series of gravitational lenses taking light on a much longer path, but it would take a lot of luck to get enough galaxies in the right places to do this, and even if it happened the image would be so degraded (distorted and dimmed) that it probably wouldn't be identifiable.
3
« on: 21/05/2013 18:13:16 »
In science, anything that can't be detected is officially regarded as "nothing". That doesn't mean it's a literal nothing, but just that it's beyond the boundaries of what can currently be explored.
4
« on: 21/05/2013 18:10:08 »
The question only makes sense if you add Newtonian time to the model, but even when you do that you find that the speed of everything else changes to match the new speed of light to the point that no difference can be detected.
5
« on: 20/05/2013 18:04:50 »
Why not make it edible? We obviously wouldn't want to eat it, but I'm thinking in terms of animal feed. All the packaging we get things in should be made of something that can then go on to be used as animal feed.
6
« on: 20/05/2013 18:02:51 »
Which means you wouldn't use it. I expect you'll have heard the expression, he has a radio face. Well, I really do have a book voice (and a radio face to boot).
7
« on: 19/05/2013 19:30:52 »
In that case, assuming that it was him singing, I can finally be impressed.
8
« on: 19/05/2013 19:26:06 »
I don't like the sound of my voice and have a very bad microphone which makes it sound even worse. Fortunately, you shouldn't need my contribution.
9
« on: 17/05/2013 17:57:21 »
Even now, it would be hard for special effects to create fake footage of people moving around on the moon - everything they do in CGI still looks to me like a cartoon, but the moon landings look real.
10
« on: 17/05/2013 17:50:40 »
It is a good question. It would be interesting to know how the density of the atmosphere affects it too, and if there's a difference between area and the type of parachute - the old round ones (which you'd use with a rocket) look a lot bigger than the steerable kind used by people today.
11
« on: 17/05/2013 17:47:32 »
I don't have enough bandwidth to play videos, so I still don't know if he was miming to the original or to his own version.
12
« on: 17/05/2013 17:42:39 »
What's really needed is a phone that gives the person at the other end a good view of the road ahead so that they can behave like a passenger and shut up when they can see that the driver needs to concentrate more on the road.
13
« on: 17/05/2013 17:37:18 »
I've noticed with digital TV coverage of formula 1 and cycle racing that the road can be very blocky due to the compression and it's extremely offputting if you look at it, though it also depends on how compressed the channel is - the compression on ITV4 is particularly bad. The same applies to ripples on water, smoke and dust in the air where it all turns into ugly flickering squares if the compression is too great, but on some channels which aren't too compressed you only see these defects if footage has been recorded on cameras that do too much compression.
With digital radio, the BBC World Service is uncomfortable to listen to because of the low bit rate, though it's infinitely better than trying to hear it on shortwave.
14
« on: 15/05/2013 18:00:41 »
Artificial intelligence will soon wipe the floor with human geniuses. We need to think about teaching children how to live good lives instead, and part of that will involve giving them back the freedom they should have rather than continuing to lock them up in suffocating institutions which turn so many of them bad.
15
« on: 15/05/2013 17:53:34 »
With FM you usually have to hold the aerial all the time to stop the thing farting, and MW now has a terrible buzz on it from those weird things that have replaced light bulbs. Digital radios cure both those problems (though they can still go a bit garbled if the signal's weak or being blocked by too much of the building you're in). The worst problem until recently was the battery consumption, but you can now get tiny digital radios that run for 8 hours on a single rechargeable AAA battery for £25 (I've been using one to try it out), so we've got to the point where it's well worth dipping a toe in the water, and once you've done that, you'll probably want to jump right in.
Edit: correction - two AAA batteries. It shows how often I don't have to change them that I was able to forget how many there are in it.
16
« on: 15/05/2013 17:38:31 »
He was clearly miming, but was he miming to his own voice or to the original track? I don't know the song or David Bowie well enough to be able to tell.
17
« on: 15/05/2013 17:36:08 »
The word "natural" can be contrasted usefully with the word "artificial", though the latter is actually a subset of the former. The words "supernatural" and "natural" could have a similar relationship, with the latter being those things made by a god, but then it's real meaning would be "artificial" while the real meaning of "supernatural" would become "natural".
Another possible meaning of "supernatural" is "magic" - something that works without any rational mechanism, and if you explore this you can disprove God with it: if he has no magical aspects, he can become a scientist and understand himself as a natural being, thereby disqualifying himself from being God, whereas if he has magical components, he is incapable of understanding how he works, in which case he is again disqualified.
There can be no such thing as the supernatural or magic other than as a description of something imaginary that cannot be, or as an incorrect description of something that isn't understood.
18
« on: 12/05/2013 15:38:47 »
You should think seriously about insurance too if you're going to fly heavy weights over people's heads.
19
« on: 10/05/2013 16:32:35 »
The thing you're continually failing to understand is that the details, really, really matter. Of course the details matter, but you're chasing all manner of kleinigkeiten instead of tackling the point that really matters. The way the clappers hit the gong, the shape of the clappers, the timing of the clappers, whether the particular point on the gong that it hits is moving or not. Use your imagination and picture the difference between ten bongers hitting the gong at the same instant in the same direction and ten bongers hitting it with the same force but at random times such that some of them reduce movement of the gong rather than adding to it. There is a clear difference between these two cases and it will result in a different amplitude for the sound produced by the movement of the gong (though it's also important not to be confused by the sound of the bongers hitting the gong as these are additional sounds and not the main event - the bongers could actually be padded such that there is no impact sound while still transferring energy to make the gong bong). In the normal case, where you hit the gong with ten clappers, the energy added to the gong is ten times the amount of energy- and most of it will NOT end up at the centre; the wave energy will spread out in different directions in an inverse law from each clapper, and only a small fraction ends up in the centre at all.
If you've got a real big gong, all ten bongers can hit it practically at the centre. In fact, we can even eliminate this trivial problem altogether by having them hit the exact same central point, not at the same time but at intervals matching the frequency of the gong bong such that the resulting waves match up exactly and add together without any cancellation. If they hit at random times instead, the amplitude after ten bongers have hit will be considerably less.
20
« on: 09/05/2013 18:46:58 »
Let me simplify things further for you. Imagine a gong with ten people hitting it with their bongers (correct technical term for gong-hitting implements not known). If they all hit the gong with their bongers at exactly the same instant, the amplitude of the sound produced will be ten times as loud as if only one hits it. There will be ten times more energy in the gong.
I'm not sure it actually works though as it's harder to push something that's already moving away from you, and ten bongers would accelerate the gong faster such that it may be hard for each bonger to transfer as much energy to it. It may be better to go back to using an example with ten sets of electromagnets. If they all hit it at different points in time though, with half of them hitting it when it's coming back towards them, they will cancel out a lot of the movement of the gong and it will be a lot quieter. No, that's not right. If the hit it at different times, they will add ten times more energy to the gong at different times. (To a pretty good approximation, it does depend a bit on precisely what way it's struck).
No, it's like trying to push a child on a swing when they're moving towards you - you end up absorbing energy from them instead and they swing less far afterwards. You still have to work hard to do this, and the energy must become heat. It might be better to think of half of them hitting the gong from the other side, so if two bongers hit the gong at the same time from opposite sides, they will cancel each other out and create heat instead. Only if they hit it at EXACTLY the same time, then they will effectively not have hit the gong; the hammer will bounce back at exactly the same speed it was struck at, and no energy will be added to the gong, but in virtually any normal case, this perfect strike will not happen.
It can happen and it's vital for science to account for that case. If you have a speaker in which the moving part contains a fixed magnet which is then made to move using electromagnets, it is possible to have ten sets of electromagnets which attempt to move the fixed magnet. If they all apply a force of 1 unit each in the same direction at the same time (which is very easy to arrange), the fixed magnet will move with an amplitude of 10 units (while a single set of electromagnets applying a force of 1 would lead to an amplitude of 1). If you make five of the electromagnets apply their force in the opposite direction, the speaker magnet won't move at all. If you let the electromagnets apply force at random times, the amplitude will be root 10. You can argue that 10 units of energy is put in in one case, no energy at all is put in in another case, and root 10 units of energy in the third, but in each case the energy will have been put into the electromagnets regardless of the result. The key point though is that if you do this, you can't then argue that the energy in the sound is the square of the amplitude, because the first case would need the sound energy to be 100 units. That is the point that needs to be addressed.
21
« on: 06/05/2013 17:34:37 »
If it ever works, it's most likely a placebo effect - the car thinks it's going to be more economical, so it is. Or, the driver thinks it's going to be more economical and drives less aggressively as a result, thereby making back the money spent. Experiments would need to take that into account with some drivers not knowing whether the devices are fitted or not.
If you don't know the device is there, it should make the car less economical due to the extra mass, so a better device to make the car go further on a tank of fuel would be a large bag of hydrogen inside the vehicle - not for burning, but just to get rid of the weight of some of the air.
22
« on: 05/05/2013 17:32:02 »
Let me simplify things further for you. Imagine a gong with ten people hitting it with their bongers (correct technical term for gong-hitting implements not known). If they all hit the gong with their bongers at exactly the same instant, the amplitude of the sound produced will be ten times as loud as if only one hits it. If they all hit it at different points in time though, with half of them hitting it when it's coming back towards them, they will cancel out a lot of the movement of the gong and it will be a lot quieter. It might be better to think of half of them hitting the gong from the other side, so if two bongers hit the gong at the same time from opposite sides, they will cancel each other out and create heat instead. If they're all deaf and blind, they will hit the gong at random times and produce an amplitude of root 10 with the sound energy supposedly being 10, but if they are able to coordinate the movement of their bongers perfectly they can generate a sustained amplitude of 10 with the sound energy supposedly being 100. It doesn't add up.
23
« on: 04/05/2013 19:46:07 »
This is a bit more subtle.
Basically if you're adding them electronically, there's no problem with that; you can get out more power than you put in, because you have an amplifier! You can't hide the problem in the amplifier. If we have a speaker with ten independent sets of magnets controling its movement, each set of magnets linked to a different input, we can have one input working on its own to produce an amplitude of 1, then add in a second (in exact alignment with the first) to produce an amplitude of 2, etc., all the way up to ten inputs generating a combined amplitude of 10. If you square the 10 to get the power, the official sound power is now ten times the amount of power that was put in. Do the experiment again with the outputs out of alignment with each other and you'll get a combined amplitude of root 10, and when you square that you'll get the sound power in the sense that it's the amount of power put in. It looks to me though as if this isn't the real sound power because you could only tap a maximum of root 10 units of energy from the sound if you had a mechanism to capture all the power in a sound wave.
24
« on: 02/05/2013 17:19:16 »
There are tribes in the Amazon which don't have words for left or right, but where they use north, south, east and west instead. They learn from an early age to keep track all the time of their orientation, but no one seems to have worked out how they do it. If you live in dense forest, most of the time you'll only get glimpses of the sky when looking directly upwards, but that could be enough to do the job. http://en.wikipedia.org/wiki/Haidinger%27s_brush may be the key to what they are doing. If you're reading this on an LCD screen, try tilting your head 45 degrees to one side and stare at a white bit of the screen for 20 seconds, then tilt your head 45 degrees to the other side and stare at the white bit of screen again - your eyes can detect polarised light, and it works on a blue sky so long as you're looking reasonably far away from the sun (so midday in the jungle is no good).
25
« on: 02/05/2013 17:10:26 »
You have to square amplitude to get power.
I believe that's your central mistake. I'd agree with that except for the problem that when you apply ten sine waves to a speaker with identical alignment, each having an amplitude of 1, the combined amplitude will be 10 rather than the square root of 10, so if you then square the amplitude 10 you get a power of 100 which is ten times as much power as you put in.
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