<p>with slight extrapolation of what you say (about the initial state of the universe being different for lots of universes, and each follows a defined path) it means you say that what i do or think is entirely dependent on the initial state of my universe. i am not saying you are wrong (i dont carry enough credibilty to do so) but i think there something you are missing. it isnt just a simple f(x) or f(t) or whatever. you need to put in something which allows decision making, or believe in fate like noone ever has before.</p>
<p>Remember this man, If the universe started out anyway different u wouldnt be here typing these messages. But thats beyond the point.
If the universe splits for every possible event then we cant think any further. There must be infinite number of universes now. I dont really understand what u r trying to say.
There is another throry that the big bang occured many times and only in one of these "bangs", the universe could be formed, i.e. the forces, matter etc developed to be favourable for the formation of the universe as it is today. But thats only a theory.
Another thing is that we know about the beginning of the universe only upto 10^-43 of a second. Scientists have not been able to determine the condition of the universe at t=0. Their math goes haywire as they reach t=0. So we dont really know the exact initial cdondition of the universe.
I hope this means anything to this thread b'cos i dont really understand what u guys are trying to discuss about.</p>
<p>
[quote]
There must be infinite number of universes now. I dont really understand what u r trying to say.
[/quote]
Well yes, Shirish, that is an actual hypothesis (infinite parallel universes). Hawking's Brief History of Time describes it pretty lucidly.</p>
<p>Well yeah, I guess that would mean I believe in fate. Except that it is impossible to predict the future. </p>
<p>I think rather than consider the universe to be some f(t) it would be easier to define it as a recursive function:</p>
<p>X = state of universe</p>
<p>lim p-> 0
Xn = X(n-p) (the n is sub-notation)</p>
<p>Maybe this summer I will read more Hawking. I remember reading his stuff in 4th grade, but now I think I will take another go at it.</p>
<p>My friend read hawking. Then he started speaking some of the most...how to say it...unbelievable...science fictional... something like that stuff. Hawkings ideas are really beyond this world. Especially abt time. He declares no such thing as actual time. Then describes arrows of time. And all that. Here's an example. No we know whats happened yesterday and not what will happen tommorrow. But if time went in reverse we would know what will happen tommorrow and not what happened yesterday. I cant understand how one can come up with such conditions. If time were reversed, yesterday will be tommorrow and tommorrow will be yesterday. Hawkings has just used english language cleverly. But most of his thinking are very interesting and mind blowing. But just unbelievable.</p>
<p>Keep in mind that the book is really for the layperson... pop sci as they call it. So he uses such sentences.</p>
<p>And laypeople repeating what they've read in popular science books can sometimes be even more dangerously ignorant than those who haven't read anything, which isn't necessarily the fault of the author.</p>
<p>
[quote]
A little learning is a dangerous thing;
Drink deep, or taste not the Pierian spring:
There shallow draughts intoxicate the brain,
And drinking largely sobers us again.
<a href="don't%20know%20the%20html%20for%20attribution,%20but%20it's%20Pope">/quote</a></p>
<p>the verse of that poem is saying that drink once from the foutain of knowledge and you will have to continue drinking, not that laypeople don't know what they're talking about because they read a bit of science</p>
<p>and isn't ironic that you're mocking "laypeople" (what are you, phds?) for talking about popular science when you are doing the exact same thing. answer me that riddle...</p>
<p>that was on the AP Lit Exam.</p>
<p>Well, certainly no reason to get nasty. I wasn't commenting on the rest of the discussion, just noting that people who "drink once from the fountain of knowledge" are, according to Pope, "dangerous" -- specifically, I was commenting on shirish's friend, who read Hawking and began repeating lots of odd things.</p>
<p>
[quote]
and isn't ironic that you're mocking "laypeople"
[/quote]
And what were you doing a few posts back, my friend? Stop for heavens' sake.</p>
<p>Tell me if the layman can ever completely understand Hawking's Thories. Most of us cant. Then why has he written a book for the layman. Just so that we too can think abt those theories and discuss them. U can't really experimant on anything to prove if there is absolute time or not. These ideas emerge from thinking deeply into the subject. If there is a fault in any of these discussions others have to point it out. Not completely stop the discussion saying that we know too little to talk abt this. That way man would never have developed to what he is today since in the beginning we knew nothing.
I understood that time reversla theory of Hawkings only in this light. If anyone has a better explanation, please post it.</p>
<p>What Happened? Why no replies? Is everyone too angry to reply? Or are all of u researching Hawking's book?</p>
<p>Actually my humble opinion of quantum mechanics is still that tis deterministic.</p>
<p>The much-quoted Heisenberg Uncertainty principle actually only deals with US (humans) trying to measure the velocity and/or position of a particle. The uncertainty comes with the fact that to measure its velocity/position, you have to shine atleast a photon onto it and see what happens. Obviously this radically changes the particles velocity/position because it is being forced to absorb/emit a photon. In reality, I think the universe is completely deterministic; we only think there is uncertainty because of what really is insurmountable INSTRUMENTAL UNCERTAINTY.</p>
<p>"The much-quoted Heisenberg Uncertainty principle actually only deals with US (humans) trying to measure the velocity and/or position of a particle. The uncertainty comes with the fact that to measure its velocity/position, you have to shine atleast a photon onto it and see what happens. Obviously this radically changes the particles velocity/position because it is being forced to absorb/emit a photon. In reality, I think the universe is completely deterministic; we only think there is uncertainty because of what really is insurmountable INSTRUMENTAL UNCERTAINTY."</p>
<p>This is untrue. Heisenberg's uncertainty is independent of the measurement.</p>
<p>"This is untrue. Heisenberg's uncertainty is independent of the measurement."</p>
<p>I'm sorry, but I disagree. Read any article about it. Heisenburg's uncertainty only comes up when you try to measure position or velocity.</p>
<p>"Some students incorrectly interpret the uncertainty principle as meaning that a measurement interferes with the system. For example, if an electron is observed in a hypothetical experiment using an optical microscope, the photon used to see the electron collides with it and makes it move, giving it an uncertainty in momentum. This is not the idea of the uncertainty principle. The uncertainty principle is independent of the measuring process and is grounded in the wave nature of matter."</p>
<p>Physics
Serway, Jewett</p>
<p>What you described is the explanation used in popular science books and articles because it's easier to convey, but it is absolutely incorrect. While there is uncertainty introduced by bouncing a photon off what you're observing, it has nothing to do with heisenberg's underlying uncertainty. If you beleive in that description so strongly, try to use it to explain single and double slit experiments from a particle perspective. There is no measurement being made in that case.</p>
<p>Sorry bombl4stik, uncertainty principle is mostly (wrongly) described as being caused due disturbance caused while measuring. Search back in this thread, I posted about this...</p>
<p>Look at it this way - if you need to measure the momentum of a particle, you need to wait at least a little amount of time (concept of instantaneous velocity ruptures here). But in that duration of time, the particle moves so position changes. To figure out this new position accurately you need the velocity, which you are trying to measure in the first place.</p>
<p>I'm gonna have to go with samwise on this. It is fundamental, not a practical limitation.</p>
<p>heisenbergs uncertainity cannot be overcome by getting better microscopes. i think it is best put this way - the system has a specific configuration or attribute or whatever but this cannot be measured by something foriegn to itself.</p>
<p>"the system has a specific configuration or attribute or whatever but this cannot be measured by something foriegn to itself."</p>
<p>That's just the thing: The particle doesn't have a definite momentum and position. It's not a "hidden variable" of any kind. All it has is a wavefunction, the square of which gives the probability of finding it in at a given point. In the words of Stephen Hawking- "Thus it seems that even God is bound by the Uncertainty Principle, and can not know both the position, and the speed, of a particle."</p>