Nagel Posted September 23, 2011 Share Posted September 23, 2011 You can't mix units like that. Maybe you should stick to slagging off Muslims on other threads. John X (BTW did you know that modern mathematics owes much of its existence to Islam?) Sheffield Forum at its finest. You couldn't make it up... Link to comment Share on other sites More sharing options...
Phanerothyme Posted September 23, 2011 Author Share Posted September 23, 2011 gah, I hate it when I post to the bottom of a page - no-one will see it now Link to comment Share on other sites More sharing options...
HeadingNorth Posted September 23, 2011 Share Posted September 23, 2011 As far as I am aware time slows down for objects travelling at ridiculous speeds........but never thought there was any possibility of time going BACKWARDS. But a couple of news reports have also suggested time travel backwards could be possible due to this find? Anyone know anything about this?? No, that won't be the case. Einstein's Theory says that you cannot travel faster than (or even as fast as) light, and also gives an equation to calculate exactly how much time will slow down for you, and how much more massive you become, the closer you get to light. If you ignore the fact that it's impossible and do the calculation anyway, it will tell you that when you reach the speed of light, your mass will be infinitely high and time will come to a complete stop; and that if you exceed the speed of light, time will flow backwards and your mass would be represented by an imaginary number. If it is discovered that neutrinos actually do move faster than light, then it will mean that Einstein was wrong, and so that equation won't apply; so you cannot conclude that time will move backwards for them. In fact you wouldn't be able to conclude anything, until you replaced Einstein's Theory with some other conjecture which explains the speed of the neutrinos, and all of the other measurements already done which have all said that Einstein was right. Link to comment Share on other sites More sharing options...
HeadingNorth Posted September 23, 2011 Share Posted September 23, 2011 You could just use the (slightly flawed) chocolate bar in a microwave method instead. You'd be measuring the wavelength of microwaves and multiplying that by their frequency to determine the speed of microwaves in air. Which should be pretty close to that of light in vacuum. At least I think that works, seems a bit circular to me but it's what I read somewhere. In essence that's exactly how it is measured nowadays. They use incredibly accurate crystals instead of a chocolate bar in a microwave, but it is by measuring wavelength and frequency, and combining the two, that the speed of light is calculated. Such experiments can be done in artificially created vacuums. Link to comment Share on other sites More sharing options...
azazel666 Posted September 23, 2011 Share Posted September 23, 2011 No, that won't be the case. Einstein's Theory says that you cannot travel faster than (or even as fast as) light, and also gives an equation to calculate exactly how much time will slow down for you, and how much more massive you become, the closer you get to light. If you ignore the fact that it's impossible and do the calculation anyway, it will tell you that when you reach the speed of light, your mass will be infinitely high and time will come to a complete stop; and that if you exceed the speed of light, time will flow backwards and your mass would be represented by an imaginary number. If it is discovered that neutrinos actually do move faster than light, then it will mean that Einstein was wrong, and so that equation won't apply; so you cannot conclude that time will move backwards for them. In fact you wouldn't be able to conclude anything, until you replaced Einstein's Theory with some other conjecture which explains the speed of the neutrinos, and all of the other measurements already done which have all said that Einstein was right. Aha! So they're basically saying that as Albert said that going back in time was impossible, if he was wrong about the speed issue he COULD be wrong about that too. Fair enough. Thanks man. Link to comment Share on other sites More sharing options...
HeadingNorth Posted September 23, 2011 Share Posted September 23, 2011 Aha! So they're basically saying that as Albert said that going back in time was impossible, if he was wrong about the speed issue he COULD be wrong about that too. Fair enough. Quite so. Einstein's entire reasoning was based on the assumption that the speed of light is always measured the same; if neutrinos can go faster than light, then that assumption itself is false, and his entire reasoning can be dismissed. (But you'd have to find some other explanation for why light always has been measureed at exactly the same speed regardless of relative motion, since that is an observable fact and must be accounted for.) Link to comment Share on other sites More sharing options...
andyofborg Posted September 23, 2011 Share Posted September 23, 2011 The classical mechanics of Newton, Copernicus etc stood for 400 years and for ordinary objects at ordinary speeds continue to work. NASA uses them to make sure that when it launches a probe it's target is in the right place even though it sometimes takes decades for the probe to get to the target. Relativity and Quantum Mechanics came 100 years ago, arose because mankind started finding things which classical mechanics couldn't explain and have withstood every challenge since then and will, in the future, continue too explain whatever it explained in the past. Most people accept that neither Relativity nor Quantum Mechanics were the ultimate description of the Universe since in certain aspects they are incompatible. If these measurements hold up then it gives us a deeper glimpse of reality which will alow us to take the next step in our understanding of the Universe. It's all rather exciting Link to comment Share on other sites More sharing options...
HeadingNorth Posted September 23, 2011 Share Posted September 23, 2011 There is something of an error in the news reports - it is impossible to get to the speed of light, however it is perfectly within relativity for something already moving faster than light to move faster than light. Think of light speed itself to be a barrier that cannot be crossed. A valid point, but since there is no evidence that tachyons exist, I left them out of discussion. It's already close to being more complicated than I can deal with! Link to comment Share on other sites More sharing options...
HeadingNorth Posted September 23, 2011 Share Posted September 23, 2011 I can handle the concepts of special relativity, as long as you don't ask me to do the calculations; I can just about understand general relativity but I don't think I could explain it very well to someone else. I try not to think about quantum mechanics. Most of it is far beyond me! Link to comment Share on other sites More sharing options...
andyofborg Posted September 23, 2011 Share Posted September 23, 2011 I try not to think about quantum mechanics. all you need is a quantum spanner Link to comment Share on other sites More sharing options...
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