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| What is TIME ??
Posted: 3/7/2007 10:05:24 PM |
At present, the only available explanation for this is that information about the present has been "transmitted" into the past in a manner that appears to determine the photons past behaviour
But when each single photon is going through the detector, how does it know that the sum of many photons should cumulatively cause the positive interference pattern? I don't think it has anything to do with the past being aware of the present...
Maybe I'm understanding the double slit wrong but the way I understand it is that even though individually each photon is sent through the slit it ends up in a random point on the screen. But then when many many photons have been shot through one after the other individually they make the ame interference pattern that would have been if all the photons had been sent at the same time. The end result of both ways of sending the photons (sending many photons individually or sending all at the same time making a wave) is a wave pattern of light. I don't know if this is the right understanding but if it is then that implies that the photon knows even if it sent as a particle that its sum of many particles will create a wave?
So doesn't that mean that some other force or energy that we don't know about is making these subatomic particles "know" where they should ultimately "be" before they "be"? | |
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| What is TIME ??
Posted: 3/7/2007 10:55:41 PM | "Neccessity is the mother of invention.", Salty Towers. So I would answer your questions with each other. Time, in that respect, helps mapping and geography. Time puts more order to travel in that now instead of just distance alone we have RATE of travel or Velocity. One tool helps and defines another. This is the order of science. It becomes more orderly as the term time is added and utilized.
But what is interesting is how time is defined very much by what it is paired with. The subtle connotation I refered to in my first post in this thread is that Time becomes more humancentric because before time there was still plenty of awareness of events passing but the markers were/are all relative to the earth and its seasons. The sun setting, the first cherry blossom, fall harvest....etc.
Time being invented very much strengthens humankind's own importance in the way it thinks about itself. It is handy but at the same time it removes us from being aware of nature and that is truly a large loss. Get what I am trying to say?
To some extent this is a large mistake, we function best when we are aware of the patterns of our world and the nature around us.
TIME (as it is defined) is simply 'one' of those tools developed in order to measure and define, in an attempt to understand/prove/justify an existing hypothesis.
Maybe we could have a thread on what is in acre? You could get into a headspin over the measurements and practical applications and even the histories of it. You might picture something tangible, like a piece of farmland, or a city block (the perception of it) you can get into the division of land, the history of civilisation, urbanisation. All sorts it CAN conjure up in our mind. All merely perceptions.
But what is an acre? Really?
Nothing. Truly nothing. It is an invented measurement for the convenience of those who needed to create a consistent definition and for their own purposes. An acre does not really exist at all.
Does time? | |
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| What is TIME ??
Posted: 3/7/2007 11:43:43 PM |
Maybe I'm understanding the double slit wrong but the way I understand it is that even though individually each photon is sent through the slit it ends up in a random point on the screen. But then when many many photons have been shot through one after the other individually they make the ame interference pattern that would have been if all the photons had been sent at the same time.
No, that is a correct understanding. The point is that, in order for the many photons, sent one at a time, to create a visible interference pattern each individual photon would still have to be interfering with itself (travelling through both slits). If the interference pattern (visible or not) were not there for each individual photon then the many photons would simply create a random pattern of dots on the film.
Regardless of whether you send one photon, many photons consecutively one at a time or many all at once, if the detector is present the interference pattern is not seen. If the detector is absent the interference pattern shows up, it simply takes many photons for it to visibly register on the film. Either way, the presence or absence of the detector makes the difference.
This holds true for the many photons sent one at a time even when the detector is added after the photons have begun their journey through the apparatus.
Even if it is due to an unknown energy rather than some indefinable information the result is still the same for the delayed-choice variation, the information or energy must still effectively travel backwards in time to produce the effect. | |
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| What is TIME ??
Posted: 3/8/2007 12:22:25 AM | If the detector is absent the interference pattern shows up, it simply takes many photons for it to visibly register on the film.
Is this with the single slit or both slits open...? I think I am missing the point of the single slit open or double slit open? My teacher told me the purpose of the slits and sensor had something to do with "tricking" the photon into something...I didn't understand when he was explaining it back then, and unfortunately it is still going right over my head...
This holds true for the many photons sent one at a time even when the detector is added after the photons have begun their journey through the apparatus.
Ok, so what are they trying to prove when they put the detector on?
Is that because the photon acts like a particle before the slit and then acts like a wave after..so they put in the detector before it hits the slit but that just makes the photon go random? Why are they putting the detector in?
Also, how is it that this experiment implies that the information must travel back in time?
What do you mean by delayed-choice variation?
Sorry for all the questions but this topic is very interesting and maybe some other people want the answers to these questions but are too scared to look dumb..
And thank you MungoJoe for your patience and answers
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LBP
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Joined: 12/27/2006
Msg: 55 | |
| What is TIME ??
Posted: 3/8/2007 1:55:41 AM | | I don't know, I need more of it though. | |
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| What is TIME ??
Posted: 3/8/2007 2:36:50 AM | Not quite. The percieved passage of time is relative to the relationship between the observed and the observer.
To a stationary observer time appears to stop for the object in motion. To an observer in motion time will appear to speed up for a stationary object.
If a clock travelling at the speed of light were observed by a stationary observer the clock would appear to have stopped while a stationary clock will appear to keep normal time.
If the observer is moving along with the clock it will appear to be keeping normal time and a stationary clock will appear to be keeping time too fast.
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YES , mungojoe.
If the clock inside the spaceship has stopped then time is not passing for them at all !
It does not take 1 year for them to travel a light year, it takes NOTHING for them !
A year passes for US on the outside.
That's what a light year is, how far light travels in a year, for us.
For the passengers on the inside the light year passes instantaniously, in fact, it doesn't exist.
In fact the whole universe doesn't exist !
The point is, that our whole experience of the universe is directly proportional to our experience of TIME.
Mass, gravity, space and time are all interrelated.
Gravity is a function of mass, space is a function of gravity, and time is a function of space.
Does a photon experience the universe ? No it doesn't.
I'm not sure what it experiences but certainly not what we do.
Is there a Theoretical Physicist in the house ? | |
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| What is TIME ??
Posted: 3/8/2007 1:23:23 PM |
If the clock inside the spaceship has stopped then time is not passing for them at all !
It does not take 1 year for them to travel a light year, it takes NOTHING for them !
The clock in the spaceship only appears to stop when viewed by the stationary observer on Earth.
For the spaceship passenger, the clock in his spaceship continues to tick along normally. For the passenger the only clock which appears to stop is the one on Earth while his local time (on the ship) remains the same.
The opposite is true for the stationary person on Earth.
If he gets in his ship, heads out as close to c as he can get and travels for one year (by his clock) he will percieve that only 1 year has passed for him. For the Earth-bound person it will appear as though ~22.2 years has passed (I did the calculations at work and that is, to the best of my recollection, the number that came up).
Because the universe outside his ship (the stuff not travelling at his speed) will also appear to compress, and c stays the same for everyone moving or not, the apparent distance will seem to be equal to 1 lightyear (for him the outside universe will appear to have become smaller. He may realize on an intellectual level that this isn't exactly the way it really is but on a sensory level it will appear that way) while the person on Earth will see him as having travelled a considerably longer distance. Bear in mind that this is individually relative to each observer.
A year passes for US on the outside.
That's what a light year is, how far light travels in a year, for us.
For the passengers on the inside the light year passes instantaniously, in fact, it doesn't exist.
This is true if the traveller uses a stationary clock as his only frame of reference but his real frame of reference is himself, his ship and the clock within. | |
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rake_
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Joined: 7/16/2006
Msg: 58 | |
| What is TIME ??
Posted: 3/8/2007 7:15:04 PM | This effect is observed even when the experiment has been arranged such that the photon is emitted before the choice of measurement by detector or no measurement is made. In this scenario, a photon which would otherwise function as a wave becomes "locked" into one path or the other after it has already begun it's route through the apparatus. In other words, the photon becomes "locked" in it's "particle state" by the mere presence of the detector even if it is still possible for it to behave as a wave. At present, the only available explanation for this is that information about the present has been "transmitted" into the past in a manner that appears to determine the photons past behaviour.
In the delayed choice quantum eraser setup, it is important to focus on the fact that the interference pattern that the signal photons made was only observable AFTER their entagled idlers were detected at D1 and D2. This is because the interference pattern made by the sgnal photons whose idlers went through D1 can only be observed AFTER the signal photons whose coresponding Idlers went through D2 are REMOVED from the pattern....and vice versa.....the assumption that with or without observation the interference pattern MUST have existed BEFORE the idlers went through D1 or D2 (rather than D3) is based on classical thinking that cause precedes observation so the "photon must have "locked" in it's "particle state" to avoid violating causality....but while in this state, the signal photon cannot be said to be here nor there nor in both places at once....in this state NOTHING at all can be assumed or said about the photon except in terms of probability....therefore, for all intents and purposes since the interference pattern cannot be observed until the D1 and D2 idlers are detected and then separated out, it is as good as saying that the interference pattern did not exist until then....as a result there is no closed-timelike loop violation of GR and causality is not violated by the wavefunction....i always try to remember that if a theory is making nonsensical predictions it means that im analyzing it incorrectly. | |
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| What is TIME ??
Posted: 3/9/2007 5:00:53 AM | OK let me get this straight.
I sit here and see a spaceship passing by at the speed of light.
I look in the window and the clock inside it has STOPPED at 12 mid. Jan 1st. 2007.
It's stopped, it's not moving.
Now, the spaceship travels a circular course that is 1 light year around and comes back 1 year later.
You say that the clock which was STOPPED has moved ahead to 12 mid. Jan 1st 2008 !
Somehow, when my back is turned, a stopped clock starts to move again ?
And only when I'm not looking at it ?
If I look at it, it won't move ?
I'm sorry but I must insist.
The year passes for us, not the spaceship.
It takes 1 year for us, for the ship to pass between 2 points 1 light year apart.
If I shoot a laser beam at an object 1 light year away, it will take 1 year my time, for it to get there.
For the spaceship, NO time passes. The light year doesn't exist.
Sure for the passengers, everything seems the same.
The problem is, the universe outside has compressed to nothingness.
The universe has gone back to it's state before the Big Bang.
Does anyone have Steven Hawkings phone number ? | |
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| What is TIME ??
Posted: 3/9/2007 5:59:54 AM |
]OK let me get this straight...
You are only considering the question from your own frame of reference not from the spaceship/travellers frame of reference
Relativity does not consider that all observers are equal, only that all observers within the same frame of reference are equal. This is a big part of the reason it is called relativity, it is relative to the frame of reference.
For the spaceship, time and space are dependant on the specific frame of reference which is different from your frame of reference. It may seem to you that the clock on the spaceship has stopped but, it only seems that way to you not to the spaceship. The person in the spaceship observes and experiences something completely different from you. | |
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| What is TIME ??
Posted: 3/9/2007 6:50:20 AM | Yes, Yes.
The point I'm trying to make is, how radically different the observers inside the ship see the universe from what we do.
Our experience of the universe is entirely dependant upon how we perceive time.
When it takes no time to travel between 2 points then that distance doesn't exist anymore.
If I shoot a laser at an object 1 light year away, it takes 1 year , my time, for it to get there.
But, for the photons which make up the laser beam, it takes no time, the distance is reduced to nothing.
When it takes no time to travel a light year, then it takes no time to traverse the whole cosmos.
The passengers in the space ship have entered into a totally different experience, a different type of space, in which the universe we see doesn't exist.
We see and experience this particular universe, photons experience something completely different.
The double slit experiment is an observation of the space which makes up the experiment.
It has nothing to do with the photons. The photons don't run up to the slits and decide which one to pass trough. To the photons, the space doesn't exist.
Rather, our space itself, has become altered by the objects in the experiment.
At least that's the way I see it. | |
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| What is TIME ??
Posted: 3/9/2007 9:53:52 AM | "You are only considering the question from your own frame of reference not from the spaceship/travellers frame of reference
Relativity does not consider that all observers are equal, only that all observers within the same frame of reference are equal. This is a big part of the reason it is called relativity, it is relative to the frame of reference.
For the spaceship, time and space are dependant on the specific frame of reference which is different from your frame of reference. It may seem to you that the clock on the spaceship has stopped but, it only seems that way to you not to the spaceship. The person in the spaceship observes and experiences something completely different from you. "
So then doesn't this come down to consciousness and the speed of light? The reason that it weird is because relativity relies on different frames of reference and thus different centres of consciousness. It is only because we are considering our consciousness of the clock and moving through space at the speed of light that we can create this paradox. It is a good thought experiment but we all know that a being who is conscious cannot travel at the speed of light. But it does point towards a link between consciousness and how it relates to time. Isn't there something inherently flawed with relativity in that the same conscious observer cannot be in two places at once? | |
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| What is TIME ??
Posted: 3/9/2007 12:38:40 PM | Imagine that you have a space ship capable of the infinite energy necessary to reach the speed of light.
You must somehow fire the engines and hit the brakes simultaneously or else, once you reach the speed of light time stops and you instantly run off the edge of the universe. Or rather, the universe collapses upon itself and becomes a pre-big bang singularity.
You will then be trapped spending an eternity waiting for a billionth of a second to pass (perhaps this is heaven ?), so that you can fire the brakes, dip below the speed of light and bring back the cosmos. Or, some future version of the cosmos after untold billions of versions have collapsed and big bangs have happened while you were waiting for a billionth of a second to pass. | |
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| What is TIME ??
Posted: 3/9/2007 12:52:06 PM | "You must somehow fire the engines and hit the brakes simultaneously or else, once you reach the speed of light time stops and you instantly run off the edge of the universe."
Except time wouldn't "stop" for the observer who is going at the speed of light. Time only would appear to stop for the statinoary observer who is observing the observer passing by at the speed of light. That's why it's relative I believe.
If you were on a spaceship and travelling at the speed of light you would have a clock on there and the minutes and seconds would be ticking away just like if you were stationary. You could count to ten mississipi and walk around on the spaceship and play chess and stuff just like if you were stationary.
I guess if you could somehow that if the stationary observ er managed to stay in a perpetual state of that instance when the speed of light observer passes by that the clock would perpetually be stopped and time would stop. So if you could get into some kind of speed of light two rotating bodies with full acceleration at the speed of light then if you were on one of those bodies you would effectively be in a constant state where time would appear tostop...or something like that...
note: I am not a physicist (pretty obvious) and I feel that this discussion is becoming more and more science-fiction. | |
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Mr H2O
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Joined: 10/31/2006
Msg: 65 | |
| What is TIME ??
Posted: 3/9/2007 2:58:48 PM | Science fiction often becomes science fact.
Imagination combined with mathematics is what it is all about.
NOBODY really truly knows - they just think they do .
If I posted hard core calculations - you all would have tuned out weeks ago :-) | |
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| What is TIME ??
Posted: 3/9/2007 4:25:48 PM |
You must somehow fire the engines and hit the brakes simultaneously or else, once you reach the speed of light time stops and you instantly run off the edge of the universe. Or rather, the universe collapses upon itself and becomes a pre-big bang singularity.
Or, and this was part of the point I tried to make a few posts back regarding the dimensional structure of the universe, you exit 4d spacetime and enter 5d spacetime where, beyond the fact that pretty much everything but time is unrecognizable owing to not knowing how, or being unable, to process 4d spatial data, time continues as normal (since the speed of light is constant for all points in space/observers. | |
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Mykis
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Joined: 12/2/2006
Msg: 67 | |
| What is TIME ??
Posted: 3/9/2007 10:05:31 PM | | Now this is the good stuff. The ''tangible aspect of ''time'' and or ''space'' may not exist unless you say it does, or rather IMAGINE it does. The universe may be as expansive as only your mind may be or may not be. I'm sure we can all imagine black holes, or even australia for that matter, but if we hav'nt been there does it exist? Just because you guys say it does does'nt mean it's true. blah blah blah | |
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Mykis
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Joined: 12/2/2006
Msg: 68 | |
| What is TIME ??
Posted: 3/10/2007 12:21:14 AM | | I think trying to ''calculate'' the ''universe'', should be regarded as a mis-demeaner in a court of law......................punishable by something.. | |
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| What is TIME ??
Posted: 3/12/2007 2:46:10 AM | | "You have been sentenced to death by tachyon emission, Sir." | |
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| What is TIME ??
Posted: 3/12/2007 9:45:01 AM | | In the real sense, there is no such thing as time. All time is is a means of measurement so that humankind can measure its progress. That is the truth too. | |
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| What is TIME ??
Posted: 3/12/2007 5:43:12 PM | an interesting article on msn today that related to this topic. here is the link with a space after the "www." another after "msnbc." and one more after "msn.".
http://www. msnbc. msn. com/id/17544598/wid/11915829?GT1=9145 | |
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| What is TIME ??
Posted: 3/12/2007 9:30:57 PM | | We are all intricately connected to and by time. We all travel through it; we all rely on it, we all measure it yet we cannot alter its purpose. Time is the measurements of moments within the existence of this our universe. | |
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gaby.s
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Joined: 2/24/2007
Msg: 73 | |
| What is TIME ??
Posted: 3/16/2007 1:19:00 PM | Time is understood on a scientific level , the difficulties come with psychological , metaphysical and even mythological definitions ..............if you have not read it , read Time The Ultimate Energy by Murry Hope , ISBN 1-85230-237-2 great stuff .....
I think that time is subjective , our personal marker for events happening in our own consciousness ......an absence or irrelevance of time means death .... to understand the concept of time beyond ones own subjectivity will probably require an understanding of the 4th dimension but that is well beyond me to explain, would hope some mathematician could post that kinda sexy topic on here ? ..... g x | |
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Mr H2O
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Joined: 10/31/2006
Msg: 74 | |
| What is TIME ??
Posted: 3/16/2007 2:48:19 PM | And just what is this "scientific level" understanding of time gaby ?
Obviously the people on this forum are not all in concurrance of a definition. | |
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| What is TIME ??
Posted: 3/16/2007 4:37:41 PM | Time in and of itself, really doesn't exist.
It is not a force like Gravity or Electromagnetism.
What we experience is a constant procession of physical events, one after the other, even on the sub-atomic level. Like a movie, this procession of events produce the illusion of time. All references to time must in some way relate to some sort of physical event.
If somehow, you could find some part of the universe where nothing, not even sub-atomic particles existed, there would be no time.
By focusing your attention during different situations you experience time in different ways. 20 minutes in a dentists chair seems like an hour, waiting in line for a movie seems to take forever but the years pass by quicker as you get older. | |
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