between3and26characterslon

Is there anyone sciency here who works in a sciency place with sciency equipment who could carry out a quick experiment to see what happens. Perhaps if anyone's still in education they might have access to the necessary apparatus. My thought is that you will see fingers of light emminating from the slits in a diffraction pattern. The biggest problem is thinking of waves of light in the same way as waves of water (water being the medium most often used to explain this phenomenon). If a photon is a quanta does this quanta split and go through both slits? Probably not. If the quanta splits is it then spread over the entire diffratcion pattern? Simply, no. A single photon or electron fired one at a time will over an extended period build up a diffraction pattern. The entire photon or electron hits your observation plate (where the diffraction pattern is seen) in one place, it is a particle (Feynman). By saying the photon knows it is being observered it would suggest the photon also knows it is approaching two slits (what do photons see with?) A particle fired at two slits will go through only one slit and hit the observation plate in only one place. If you emit a single particle, and you know it's a single particle, and you receive that single particle, and you know you've received a single particle, then why is it not a single particle in between. If you carried out the double slit experiment with laser light (firing xnth photons) and fill your experiment with just enough smoke to see the laser beam you would see a single beam of light hit the double slits and split into fingers and a diffraction pattern. You will see the beam of light becasue a photon has entered your eye, that photon will have bounced of a particle of smoke. If you can see an uninterupted beam of light followed by several fingers of uniterupted beams of light then at evey point along those beams of light the photon must be a photon. I'm not trying to rewrite physics here, I'm trying to understand it. I don't work in this field and don't have the equipment to carry out experiments nor the education to know enough to put all the pieces together or the time to do it. What I can do is think and look at things logically which inevitably leads to questions sbout my understanding (or lack thereof).

^^ Don't really understand what you are saying^^ The point I was asking about is that the interference in the double slit experiment is not interference between photons or electrons it's that every single photon or electron only ever interferes with itself whether fired individually or en mass. If you were to use two lasers firing at single slits you would not get the same interference pattern so interference can not be between two photons (another interesting experiment would be to split a single source of light into two signals and fire them at two appertures and see if interference happens in this case, I expect it won't) The point is that the electron does not know you are watching, if you detect the electron by using an electromagnetic device you will cause it to only go through one slit. But what would happen if you set up the experiment firing the electron through a reduced pressure gas (one that would illuminate when excited by a high energy electron). Would you see fingers of illuminated gas spreading out from the slits?

Sometimes things are really obvious and you just don't notice them. Here's what I was thinking. If you have electron gun A firing electrons at slits A and B and you will get a difraction pattern. However, If you have one E-gun A firing at slit A and another E-gun B firing at slit B and there is a wall between slit A and B (on the E-gun side) you will not get a difraction pattern. My assumption had always been that electron A inteferes with electron B but this is not the case, electron A inteferes with electron A. (<that's the obvious bit) This is true when on electron is fired at a time and when 'n' electrons are fired they all interfere with themselves not each other. (<that's what I just realised) Now its said that if you were to fire one electron at a time it will travel through both slits as a wave and interfere with itself on the other side but only of you don't observe it. If you do observe it it will only go through one slit (I beleive this is true regardless whether you observe it before the slits or after the slits) What would you see if you fired a laser at a double slit so that you could see a difraction pattern and then filled your experiment with some smoke. Would you see a single line of light hitting a plate and then fan out in lighter and darker 'fingers'. Is this not making observations throughout the experiment, before and after the slits. Do you not still get a difraction pattern. Maybe I'm not understanding or knowing enough. Your thoughts... (editted for spelling and grammer) (edited again to spell edited properly)

There was a discussion some months back about travelling to our nearest star, Proxima Centauri, and how long it would take to get there if you accelerated to the speed of light at 1g. A 1g acceleration would be a reasonable acceleration to be comfortable to those who are travelling. Some of the more mathematicaly inclined and knowledgeable proffered the suggestion it would take about 7 years (if I remember correctly) whereas I said I had heard it would take some 245 years. So my question is this; if our Sun and Proxima Centauri are rigidly attached to an inertial frame A with time t and our mode of transport has its own frame B with time t' then is it correct to say that an acceleration of 1g in A = 1g in B. In other words if time for B t'=t/2 an accereration of 1g in A would = 2gin B. This means to maintain a 1g acceleration aboard our transport the acceleration as measured from the intertial frame would decrease. If this is correct how long would it take, both in the inertial frame and our transport's frame, to accelerate to c at 1g and travel for the necessary distance to allow us to turn round and decellerate at 1g and arrive at Proxima Centauri?

It appears you would do well to learn what's in the box before thinking out of it (no offence intended)

http://www.einstein-online.info/spotlights/dialectic

I don't think you've quite understood what Cap'n was getting at here. Have a read of this http://www.efm.leeds...al_analysis.htm What it is saying is that all the terms in an equation not only have units but have dimensions as well, so for instance: velocity 'v' has units of ms-1 and dimensions of LT -1 (where L=length and T=time) acceleration 'a' has units of ms-2 and dimensions of LT -2 so if you wrote an equation v=a you can test its validity by checking its dimensions and you can see. LT -1 ≠ LT -2 In terms of dimensions used in an equation the lefthand side must equal the righthand side. In regards to your equation to 'tweek' Einstein's theory I'm affraid you can not pull an equation out of thin air, presume it's correct and then reverse engineer it to find out why it's correct. What Swansont is saying is the E=mc2 was the result of a lot of work not the beggining.

Maybe the OP is asking is the Sol AND its constant nature just something we measure or is it something derived from first principles and then confirmed experimentally. What theory, if any, predicts the Sol. Is there something that predicts that it should be 3*108 ms-1 or do we just have to accept the fact that is what it is?

It stops everything happening all at once

I'm sure everyone is aware of the experiment whereby a moicrowave signal was split in two and sent to two equidistant receivers. One of the signals was uninterupted whilst the other was blocked by a bar of copper. Upon closer examination of the osciloscope it was discovered that not only did a small signal make it through the copper block but it actually preceded the unhindered signal. The conclusion reported by the dimwits in the press was faster than light speed signals, the conclusion drawn by the scientists conducting the experiment was quantum tunneling (the early signal was exactly equivalent to the thickness of the copper block). The point is, though the one signal did not "actually" travel faster than light it "effectively" travelled faster than light but it still arrived after it was sent... cause preceded effect. If a tachyon is sent to a receiver 1Ly away it might only take 6 months to get there but it will still arrive 6 months after it was sent... cause still precedes effect. The only problem arrises in the frame of the tachyon itself. It's only in its frame that effect precedes cause, that it arrives before it is sent.

And if you have two buckets spinning in opposite directions is the universe spinning the other way to boths buckets at the same time, or two buckets spinning in the same direction at different rates. What about if only one bucket is spinning (and the universe is therefore spinning in the opposite direction) would this not cause the other bucket to spin.

Light dissipates from a spherical body following the 1/r2 rule, the amount of light hitting you from 8 million miles from Saturn is 4 times what it would be from 16 million miles away and many times more than from 800 million miles away. The amount of light reaching you from Saturn is tiny, how big would your telescope need to be to collect as much light as your eye would from 8 million miles? Or how long an exposure would you need to collect as much information? A telescope does not make things closer it makes things appear bigger, much like zooming in on a picture on your computer and you don't expend megawatts of energy doing that.

what about a reflected or refracted photon, in both cases a change of direction has occurred and therefore an acceleration.

If it existed in something we would then have to explain where the thing we existed in existed in itself. It would be turtles all the way down!

Einstein said that in Euclidian geometry a straight line is uniquely defined as being the shortest distance between two points situated upon it. By using this rule one can test whether the statement "a line is straight" is true or false. What one can not do is test the if rule is true or false. You can not ask if more than one straight line can pass between two points. You can not determine whether that is true or false, if it were a rule it would lead to different conclusions. So science is based on the notion of rules, if the rules lead to consequences that agree with observation they are good rules and if they don't they are bad rules. The Principle of Relativity first described by Galileo is that all frames that are at rest with each other or in uniform rectilinear translation to each other must all have laws of physics wich are no less simple than each other. In other words there is no difference between moving in a straight line at a constant speed and being stationary, if you drop a ball it falls to the ground in a predictable way in either frame. This is a rule supported by evidence, you've probably been on a plane and you know that when you drop something on a plane it falls to the floor. The plane's speed relative to the ground does not affect the laws of physics in the plane. Then you have another rule of physics which is that the speed of light is constant. In every experiment conducted the speed of light in vacuo is measured to be constant. If someone on the ground shot a bullet at 1000mph and you flew past at 800mph you would measure the bullet to be travelling at 200mph. The difference is with light you will both measure it to be the same speed. Einstein realised this paradox between the principle of relativity and the constant speed of light to all observers could be resolved if one were to consider that time and space were not constant. So if you are on a moving vehicle and you drop a ball you see it fall straight down but someone standing on the ground watching you go past will see your ball describe an arc as it falls to the ground. This means that although you do not have to take into account any motion when considering the physics of the frame you are in you do have to when considering the physics of a frame that is moving relative to you. You have to consider that time is dilated and length is contracted in the frame that is moving relative to you. That is its time and length change relative to yours, if you were to catch up with that frame and be at rest with it you would consider your time and length to be normal. Getting back to the twins you can approximate that the distance between our sun and proxima senturi is constant. This then gives you two fixed points of an enormous frame of reference which you can consider to be at rest. Both twins start of at rest relative to this frame and only one twin gains motion relative to this frame therefore only one twin is affected by time dilation and when he/she returns is younger that their sibling. Hope that makes some sense.

Take a look here http://www.einstein-online.info/spotlights/sr

My apologies if I'm hijacking this thread, a Moderator can move it if necessary. On the subject of Occam's razor. You have a system and you have two explanations for that system, one of those explanations is very complex and the other is quite simple. Could one conclude that the more complex explanation would necessarily embibe upon that system a higher entropy and the simpler explanation a lower entropy. Is it not therefore the direction of entropy, from high to low, that gives rise to Occam's razor and thus would indicate that the simpler explanation is more likely. On that note would a universe that has a higher state of entropy require a more complex exlanation than a universe in a lower state of entropy and, as a consequence of that, will our explanation of the universe get simpler as the universe gets older? Of course if two different explanations both give the same entropy to a system then the above is nonsense. (EDIT: I may have gotten the direction of entropy wrong)

Maybe if you had some very accurate clocks you could measure relatavistic effects rather than pre-supposing them. Are you invalidating the most fundamental law of physics? No. You will measure an acceleration to a speed of 0.01c from the frame you are in to the next frame. When you move from that frame to the next one you will again measure an acceleration of the next frame to 0.01c. This conserves the principle of relativity. If you were to stay in your initial frame and measure each sucessive frame from there you will notice they increase in velocity in increments progressively smaller than 0.01c, this is confirmed by comparing their clocks, and this is fundamentaly the special theory of relativity. edited for spelling

Is it not the case that in TBB theory the early stages of the universe were too hot for matter to form. You would then have space but no mass. If so my qustion would be did gravity exist before mass and was this the inflationary period. Anyway the point I was really getting at is that space without matter seems to be an accepted part of another theory. Space without field is somewhat different.

My understanding of the big bang model is that matter did not exist until some time after TBB. If the theory says that space existed before matter existed then it-(the theory) implies space can exist independant of matter. ------------- Is it so difficult to imagine we can only see a finite amount of an infinite Universe. When I look out of my window, over the sea, I can see the Horizon. I wonder what would happen if I could travel to the Horizon? Is there anything on the other side of it? Would I disappear from one side of the Earth and reappear on the other side? Is there any point in speculating what might be on the other side of it? As I move the horizon moves so I can never reach it so it is nonsense to ask what will happen if I get there because I never will. But what would happen if I got in my boat and rowed out to sea, I would be able to see farther than I could when I was on land and now I can see another island that I couldn't see before. That's because the distance between my island and the new island is constant, but what if the amount of sea between us is increasing faster than I can row. I will never see this new island no matter how fast or for how long I row. Suppose now that the was a third island half way between my island and the new one, I of course will never know about the 'new island' because I can not see it from my island nor can I travel to it fast enough to be able to see it. An observer on the third island however can see the 'new island' for he is close enough to see it, but it is moving away from him also. If I were to row to the third island (which is also moving away from me) it would take me so long to get there that the 'new island' will have dissapeared from the third island's view before I get there. I will never be abe to see the new island, although there are things beyond my horizon I will never be able to see them. In fact (figure of speach) more and more things will dissappear beyond my horizon never to be seen again.

Then you are mistaken. My objective is not to learn more things about this subject but rather to understand one thing. I wasn't seeking to broaden my knowledge, I wanted to deepen my understanding. If someone asked me what differentiating and integrating were I'd still have to answer "I don't know" Ok so the bits in bold are where I'm struggling, would you be so kind as to put some simple equations in so I can see what is going on. I got distracted by the rest of the posts here but now I've given this a proper read it is starting to make sense. Thanks Cap'n

This is a good explanation for me (if you've read any of my other posts you will notice a distinct absense of maths, I am more comfortable with concepts). Can I ask, if you plotted a graph of 'gravitational force of attraction against distance from the centre' following the 1/r2 rule you would get a curved graph. Could you differentiate and integrate this graph and if so how would you and what would it tell you? DrRocket, all those squiggly lines you keep posting mean absolutely nothing to me just yet, you may as well be speaking Klingon (which you probably do... phnarrr! no offence) thanx for your input, and sorry to single you out, but you're way over my head. Perhaps you're not up to the challenge of coming down to my level....?

What I mean is, in my limited experience, the answers to science or something analogous to an answer is quite often staring us in the face. I'm sure people used to wonder at rainbows and when Newton used a prism to make his own rainbow and prove light was made of many colours people would have realised that the knowledge that light was made of many colours was staring them in the face all along i.e. rainbows. So now take a body of rainfall 1km3 and shine some Sun at it. You will see a rainbow and so will I but we will not see the same rainbow. If you were to define the ends of the rainbow as a and b in relation to yourself c then mine would be defined as a', b' and c'. So the rainbow exists everwhere within this haze of rain but you can not be certain where exactly it is (or at least we can not agree where it is), and it is only there when you look at it (observe it). This is analogous to the quantum world (more precisely is a good analogy to my limitted knowledge and understnding of the quantum world) and it is relative to every observer which is a good analogy to the macro world. If the Universe is granular, which is a developing theory (and I guess that could mean either descrete untits of spacetime or a continuum which is mixed up at a quantum level), it makes the rainbow analogy even more appealing. You could then think that ou universe is a 'rainbow' in a haze of a much bigger Universe. We all think we see the same Universe because it's soo big but if we could instantly travel millions of lightyears we might be able to see parts of the Universe we can't see from here. Every observer sees a different Universe. So the analogy works from the micro to the macro Universe (for me anyway). But like I said it is not a theory, I have no thorough arguement or real evidence, so really it's more of a musing.

No insult taken, I havent a clue what you're talking aout. Nor do I have any clue why this arguement about FTC ensued. Sorry Zone Ranger but your comment was irrelevant here because it meant nothing to me and didn't help in any way to answer my original question.

Thanks, this is more my level. Thanks to everyone else as well.