View Full Version : I Need Brian Cox.
Okay.
For those of you who don't mind a bit of brain straining watch this:
Dr Quantum (http://youtu.be/DfPeprQ7oGc)
Right. Hmm. I get the whole wave scatter thing and the pattern on the back wall.
I can *kind* of accept the electron becoming waves of potential... but I don't understand it. I just accept it.
As for the whole observing thing... seriously... WTF?!?!
What?!! WHAaaaaa!? Why... why... how does the electron know it's being watched or measured?! HOW!? It... how... it's just an electron... I just... how... ?!?
My Pa said that it's something about observation changes space and time. Which I don't get.
Please someone... this kept me up most of last night. Help me hire Brian Cox for the week. I need his brain.
No ideas people?! No simple way of putting it?!
Mc Chrispycoats suggested it was magic. Which I kinda liked.
Bum nuggets!! Bum bum bum nuggets! *wish I was clever to get this*
semi-pro waster
13-11-2011, 18:30
Essentially as I understand it it's the act of measurement that cause the particle to "commit" to one slit or the other i.e. to measure where a electron is you need a photon to interact with it and that changes how it behaves. If you don't measure then it is free to go through both slits, either one or neither.
It's difficult to think of a correlating example in the non-quantum world because once beyond that scale things will tend to behave in relatively predictable ways normally and cannot appear to be in two places at once.
However I'm not a scientist so I may be completely wrong with my understanding.
The problem is that no-one understands it, we've simply come up with a hypothesis that best fits. The only plausible explanation is that the particle goes through both slits... which is clearly implausible. Quantum theory explains it, but not by any knowledge or discovery we've yet made. Until we find a way of observing electrons without interacting with them we may never know the truth. I've basically come to peace with the fact that I'm only smart enough to know that I'll never understand it. :D That is, until some genius works it out and is able to explain it in terms we can all understand.
Lex parsimoniae. The simplest explanation is usually the most likely. Since we don't really know we have to theorise and as such the perceived correct answer is the duality of existence of a particle. Observation changes everything although not directly, IT. Doesn't know it's being watched but the fact it's being watched means that it's state is different.
I kinda like these theories as they're beautifully impossible to grasp sometimes. This is why I like the fact that spiritual beliefs and science tie in with one another as whilst they can clash they can support one another too. If you are of the belief of a greater being(s) then all particles are always being observed hence why they can exist, but until we observe them they hold multiple states.
It's all rather fascinating. I love the light duality too that it behaves like a wave but like a particle too.
volospian
14-11-2011, 11:53
It's an interesting conundrum... It strongly suggests, imo, the plausibility of the "multiverse" style theories (or, to put it more simply, Terry Pratchetts idea of "the tousers of time").
As I understand it (which is admittedly not much) it suggests that a particle can exist in several states (or places or "spins" or whatever, for now we'll ignore the technical minutiae) but we cannot entirely know the state of that particle until it is observed. Observation then "locks" that particle into place... however, it only "locks" it into that particular moment of time (and therefore, space).
The ensuing "reaility" is then based upon the position of that particle at that particular moment in time. It doesn't specifically "lock" the underlying quantum effect, per se, it just means that an "observation" means we only detect it in that state and that that state then becomes our reality. If we could go back and observe it again, the result may be different... although we wouldn't have the original result for us to compare it to... so it cannot be different as there can only be one result.
Anyway, the fact that our reality is based only upon the observed state of particles suggest that there are an infinite number of alternatives that can exist as every possible permutation of every particle could be observed. If this is so, I wonder what holds this "reality" together?
It's worth remembering that, as the guys have said, we don't really understand half of this stuff. I mean, I don't really understand the nature of time itself. It's easy to say we understand "time" as a chronological series of events, and that everything flows forwards in time, but is time the driving force, or just a byproduct of entropy, or gravity, or does quantum exist outside the "time" field? We believe that time works differently in different gravities, so why is that if it is not a "force" in its own right?
Also, if time is not a constant, how can we measure the "speed" of light (as calculated as the distance travelled in a set time). This suggests to me that the speed of light cannot be "constant" as it can travel the same distance in different times as it passes through different gravities, yet scientists insist it is a constant and nothing can go faster... but, if everything is relative, if I were travelling "east" at 3/4 the speed of light, and you were travelling west at the same speed... we would appear to be travelling away from each other at one and a half times the speed of light, but if we were both travelling east at that speed, we wouldn't appear to be moving at all... This suggests that it is only a constant in relation to a specific moment in the space/time continuum... but that's a bit pointless as the moment of space/time that existed when I started this sentence has long since passed... it all just boggles the mind :)
I also need Brian Cox, however, science has nothing to do with it. I just want to name him George and hug him and pet him and squeeze him and pat him........ :p
leowyatt
14-11-2011, 20:38
I also need Brian Cox, however, science has nothing to do with it. I just want to name him George and hug him and pet him and squeeze him and pat him........ :p
And just get him to keep telling you things are brilliant :D
What no mention of Schrödinger's cat? http://en.wikipedia.org/wiki/Schr%C3%B6dinger%27s_cat
It's much the same thing - just expressed in a different way. :)
Yep it's pretTy darn confusing.
Oh and need Morgan freeman, love his voice and prefer the content. Wonders of the universe is far to cinematography and that makes it annoying. Put some graphics up, not a artistic shot of a desert with Brian randomly posing.
Pumpkinstew
14-11-2011, 21:30
Um, well, if you're happy with idea that matter and energy are equivalent that's always a good place to start.
Then you have to start thinking of particles as not being finite. Instead they're little bundles of waves which have a probability density which localises the vast majority of that energy in that one region of space (and time).
This wiki entry is a bit formal but has a useful graphic (http://en.wikipedia.org/wiki/Wave-particle_duality#Treatment_in_modern_quantum_mecha nics)
That gets you to the interference pattern (wavelike behaviour) being created by particles. And other phenomena such as quantum tunnelling and Hawking Radiation.
Then the thorny bit - how does observing the wave/particle cause it to behave more like a particle than a wave? Especially as it may have passed through the slit you aren't observing!
There isn't a definitive answer that I know of. Relational Quantum Mechanics (http://en.wikipedia.org/wiki/Relational_quantum_mechanics) has a bash at explaining it. But really it comes down to saying the same thing - by observing the quantum system you force it into a state instead of a range of possible states at the point in time and space when it is passing through the slits. Schrodingers equation is time and space dependent remember.
Importantly though in RQM the observer becomes part of the quantum sytem, and different observers may see different, but still correct, outcomes because the equation continues to evolve with time.
It's worth pointing out though that various detectors and particles have been used in the double slit experiment and the level to which the interference pattern is disturbed varies. this strongly suggests that the fundamental interation between the detector and the wave/particle at the point in space time at which it passes through the slits is what varies the strength of the interference pattern.
The QM I did at university is a hazy and distant memory though and i may have gotten totally the wrong end of the stick:o. If you were still in Exeter I could have suggested a professor who would know for sure. I may have an old textbook at work still. I'll have a thumb through it tomorrow and see if it becomes any clearer.
Pumpkinstew
14-11-2011, 21:39
What no mention of Schrödinger's cat?
It does illustrate the RQM (http://en.wikipedia.org/wiki/Schr%C3%B6dinger%27s_cat#Relational_interpretation ) way of looking at things quite nicely.:)
Before the box is opened, the cat, by nature of it being alive or dead, has information about the state of the apparatus
;D Poor cat.
;D Poor cat.
Of course, it seems that Schrödinger completely neglected the obvious solution to the problem - the zombie cat. ;D
One of my favourite books - "In Search of Schrodinger's Cat" by John Gribbin.
Okay... well the brain is a bit more accepting of the comments here! It makes me feel slightly better that it's all a bit mind boggling to all!
I like Schros Kitty Cat. I understood all of that (I say understood because I looked at it years ago and seemed to absorb it quite comfortably without my mind exploding. I'm sure I need a refresher read of it all).
I think it frustrates me that I have to just *accept* things and not be able to understand why!
Stew - Darnit! I am in Exeter soon but on business! Boo hiss!
Thanking you people and your brain strains! I've just started reading Stephen Hawkings latest book but have paused due to the whole CERN discovery. I have this fear of reading his book, understanding it for the first time ever only to be told it's all messed up and wrong! Hahahaa!
Something tells me my prophecy of me being able to comprehend it in the first place is a slim chance of occurring! ;)
Creature
15-11-2011, 00:37
Mc Chrispycoates suggested it was magic. Which I kinda liked.I still stand by this. That, or pixies.
volospian
15-11-2011, 10:12
Something tells me my prophecy of me being able to comprehend it in the first place is a slim chance of occurring! ;)
I doubt many people can really, fully, comprehend it all. We have snippets of information that generally explains some things in a very simplistic manner, such as schrodinger's cat but the deep stuff is, funnily enough, all relative.
You can't really get your head around D until you fully understand the concept of C on which it is built, and you can't fully understand C until you really get B, and even that is hard to understand until you know all about A.
I mean, think about gravity. You think you understand gravity, it's what makes apples fall out of trees and so on, but what is gravity? What is going on to make things pull themselves together, or spin around each other in space. The earth, for example, stays in a faily short orbit around the sun, and yet comets, which are much smaller and presumably much less dense seem to have orbits that take them way out as far as Pluto... so, if the sun can affect bodies that far out... how does the earth stay where it is and not crash into the sun? I know acceleration comes into play, but how are gravity and acceleration linked? Is acceleration a "force" like gravity? What's going on out there??
It's like trying to imagine the size of the universe, or what came "before" it. The accepted answer seems to be "nothing" as there was no "time" prior to the big bang, however, one model of the universe allows for expansion to stop and gravity to pull everything back into a "big crunch". This *may* be followed by a "big bounce" as everything is compressed until it reaches a point where the singularity explodes again into another big bang, so, based upon this theory, the universe could have formed and collapsed billions of universes before. We all may have lived our lives billions of times already...
It's also boggling to imagine what comes after it. Some theories suggest a "big rip" where the universe carries on expanding at an increasing rate until the expansion rate becomes infinite and the universe simply rips itself apart. If that's the case... what will it expand into? What is "beyond" our universe? It's hard to concieve of an expanding universe with nothing to expand into. The infinite is very difficult to get your head around...
Pumpkinstew
15-11-2011, 13:27
I mean, think about gravity. You think you understand gravity, it's what makes apples fall out of trees and so on, but what is gravity?
The standard model attempts to unify the four (or three depending on who you ask) forces of gravity, electroweak and strong nuclear. The last two are exerted by the exchage of particles. The supposition is that gravity should also be exerted by an exchange particle (the graviton) but it hasn't been observed and so the search for a GUT (grand unified theory) goes on.
I know acceleration comes into play, but how are gravity and acceleration linked? Is acceleration a "force" like gravity?
Yep, it comes into play. F=ma according to Newton. And this non-relativistic version is super accurate for describing how celestial bodies move around.
Acceleration isn't a force in the same way as gravity. It's the result of an unbalanced force acting on a mass.
one model of the universe allows for expansion to stop and gravity to pull everything back into a "big crunch".
Largely out of fashion now since it's been shown that the rate at which the universe is expanding is increasing not slowing down. No-one knows why this is. It's what the search for Dark Energy (ooooh, sounds spooky) is all about. Explaining the expansion of the universe.
volospian
15-11-2011, 15:30
The standard model attempts to unify the four (or three depending on who you ask) forces of gravity, electroweak and strong nuclear. The last two are exerted by the exchage of particles. The supposition is that gravity should also be exerted by an exchange particle (the graviton) but it hasn't been observed and so the search for a GUT (grand unified theory) goes on.
I've been reading lately about the superfluid vacuum theory, and while I don't pretend to understand it fully (or even partially :)) it makes more sense to me than the concept of gravitons.
Yep, it comes into play. F=ma according to Newton. And this non-relativistic version is super accurate for describing how celestial bodies move around.
Acceleration isn't a force in the same way as gravity. It's the result of an unbalanced force acting on a mass.
Well, ok... it is described as not being a "force like gravity", but the effects are both so similar... both the addition of "gravity" and the addition of "acceleration" increase mass, and both dilate time... is it not possible that acceleration is gravity, and vice versa?
I mean, an object at rest is still potentially subject to some kind of gravity, wherever it is.
To accelerate an object we need to add some kind of "force" which I presume is a transfer of energy? Adding energy should increase its mass anyway, shouldn't it? and increasing mass also increases gravitational pull, doesn't it, so adding energy increases gravity?
so... what we term "acceleration" is simply the "addition of gravity" above and beyond the local gravity field caused by increasing the relative mass by the application of energy... sort of thing... ?
Largely out of fashion now since it's been shown that the rate at which the universe is expanding is increasing not slowing down. No-one knows why this is. It's what the search for Dark Energy (ooooh, sounds spooky) is all about. Explaining the expansion of the universe.
Yep, that's why I included the "big rip" theory...
volospian
15-11-2011, 15:34
ps...
Mrs. Schroedinger to Mr. Schroedinger: What the hell did you do to the cat? It looks half dead!
I didn't mean understand what I posted as in fully... just understand the theories a bit more which I will be tackling in this book I'm reading!
I'm sure I was doing this to feel more intelligent but it just makes my brain ache and collapse!
Loving reading the posts! I would spend more time responding but am exhausted from a long day!
Bed time and a zombie book methinks! Simple evening for me, Stephen Hawkings can wait! :)
So CERN repeated the FTL neutrino results. Anyone care to suggest what they're doing wrong before we all have to tear up those text books. :)
Um wear gloves to tear up the rule books.
The reason they repeated the experiment was to answer any criticism. So it's getting more and more likely, still far away from bring confirmed, but getting closer. If true maybe that will make the uniformed solution easier.
The problem is that no-one understands it, we've simply come up with a hypothesis that best fits.
Always loved this bit from Stargate SG1:
NARIM: Ah! Kulivrian physics. An atom state is indeterminate until measured by an outside observer.
CARTER: We call it quantum physics. You know the theory?
NARIM: Yeah, I've studied it... in among other misconceptions of elementary science.
CARTER: Misconception? You telling me that you guys have licked quantum physics?
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