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#551
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The travel time to the target is irrelevant. The one second pulse hits the target. After reflection the pulse will be less than one second. Goodbye. |
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#552
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Tom, I encourage you to take another look at Bunny's post a few pages ago:
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error 3), in my mind the most basic Quote:
I am very much a layman, so I apologize for any errors I may have made myself. My point is that even someone with a very rudimentary knowledge of basic physics can see the gaping holes in your reasoning. Your unwillingness to address these errors (among many others) proves either that you 1) aren't arguing in good faith, or 2) are suffering from a serious case of the Dunning-Kruger effect, as has already been mentioned, or perhaps some combination of the two. I'll be surprised and impressed if you actually address the errors in the quotations I posted. Last edited by John Cazale; 05-15-2012 at 02:16 PM. |
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#553
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Painted yourself into a corner, I see.
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#554
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The reflector does not reflect 20 cycles in a second. If you remember, I fell into that trap with ZenBeam. The reflector reflects 10 cycles, yes. But it reflects them in half a second not one second, so the frequency is doubled. Quote:
Paragraph three - incorrect. 200 pulses have not been reflected, only 100 have been reflected, but they have been reflected in half the time. Paragraph four - same as three. You are confusing pulses (cycles - period) with cycles per second, which is Hertz. Quote:
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Point 1. The beach ball. I was using poetic licence. A beach ball has a very low weight to size ratio, the characteristics are unknown, and air resistance plays a big part. Substitute for a ball of known characteristics, and use that. The characteristics of this ball are that is heavy, so air resistance can be (nearly) ignored, and it reforms at 10kph. When this ball is hit by a bat and therefore compressed, it will compress to half its size in the direction it is hit, and then reform again. The bat moving at 10kph (WRT the ground) hits the ball, which compresses while still in contact with the bat. The bat is still moving at 10kph and the ball is fully compressed. Now bat and ball are both moving at 10kph WRT the ground. The ball reforms to its original shape while the surface of the ball is still in contact with the bat and is attempting to move towards the bat at 10kph (WRT the bat). As the two surfaces are in contact, this means that the centre of mass of the ball is pushed away from the bat at 10kph. The bat is still moving at 10kph WRT the ground, so the ball is now moving at 20kph WRT the ground. We have moved on since then. Now you tell me why I am wrong in saying the Sagnac effect is incompatible with radar. See my posting #547. |
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#555
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Let's again place the transmitter at A and the reflector at B.
Let's nail down our description of the rotating reference frame co-rotating with A. In this reference frame neither A or B moves, and there's a constant distance between them. The speed of light differs in the AB and BA direction due to it being a rotating reference frame. Let's look at just two wavefronts, one cycle, emitted from A at 25GHz, i.e. 40 ps apart. If we start transmitting at t=0, the second wavefront will be emitted at t=40 ps. We can call travel time from A to B tAB. The first wavefront will hit B at tAB, the second wavefront will hit B at tAB + 40 ps As they hit they are reflected. The first wavefront is reflected at tAB, the second wavefront is reflected at tAB + 40 ps Travel time from B to A is different from the travel time from A to B. We can call travel time from B to A tBA. The first wavefront will return to A at tAB + tBA. The second wavefront will return to B at tAB + tBA + 40 ps They're received at A on their return 40 ps apart, which is 25GHz. Now I suspect you'll disagree that A and B are not moving, but in the reference frame co-rotating with A they are still. That's what's meant by a co-rotating reference frame. One can pick an infinity of other reference frames, both rotating, accelerated and inertial, where A and B do move, but the only one that makes sense to examine (the other's will give equivalent results, just with horrible math) is an inertial one co-moving with A and B's center of rotation. In that frame A and B do have acceleration and velocity, but as in all other inertial frames of reference, c is constant and the radial velocity between co-rotating points A and B is 0. Now the following is just an animation I made for my own amusement which shows "photons" moving with or against the direction of rotation, it's not meant to really enlighten anyone in this thread. But it's as good a place to share it as any: http://www.geogebratube.org/student/m9696 (requires up to date Java, and in my case, use of my second choice browser) |
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#556
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I'm sorry, Tom, but you are clearly being disingenuous. You only "explained" one of your obvious errors. Is this
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Again, the lack of knowledge exhibited in that quotation means you just don't have the ability (at this time) to make sense of something like relativity. Lastly, a few times throughout the discussion you've expressed interest in converting others to your view. If you really want the ether theory to gain traction I'd encourage you yourself to stop talking about it, as you are supremely unconvincing. Last edited by John Cazale; 05-16-2012 at 07:27 PM. |
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#557
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#558
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Again: I know what velocity is. You seem to not. If you don't understand velocity, you couldn't possibly understand the physics you're asking about. Last edited by John Cazale; 05-17-2012 at 04:29 PM. |
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#559
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Isn't this the core of the issue? According to SR, this doesn't happen. It's also never been observed to happen.
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#560
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Your posting contains another mistake, but reading it made me realize that there is a mistake in my work also. I will get to that later, but now to yours. Not a quote, but you said “On the outward journey, to the reflector, the radar pulse is traveling at say 300,000,000 M/s, with a time between wavecrests of 40 ps. On the return journey, at say 200,000,000 M/s, the wavecrests are still 40 ps apart.” That is what you put ( I may have the velocity/direction wrong, but the maths will still be correct). You also said that the frequency is 25 Gig in both directions. For the outward pulse, the wavecrests are 40 ps apart in time, so they have moved 0.003 M in that time. This corresponds to a frequency of : F = V / W = 3e8 / 0.012 = 25 Gig They are reflected also at 40 ps apart. Now the velocity is not 3e8 but is 2e8 (the return pulse). The wavecrests have moved 0.002 M in that time. This corresponds to a frequency of : F = V / W = 2e8 / 0.012 = 16,666,666,666.66 Gig This took me by surprise, and I looked harder at my previous postings. There is a mistake there, but as I am about to leave for a well earned holiday in Crete, you will have to wait until my return for my announcement. Of course you are all allowed to speculate in my absence. A quick answer to Trinopus. Relativity says that the speed of light is a constant (c) in any and all IFRs. To be constant in an IFR, it cannot be constant in an RFR. It is for that very reason that a ring laser (Sagnac interferometer) works. Read up on that. To John Cazale. You consider yourself a layman, but that does not stop you disagreeing with the points I have made in this discussion. You cannot hide behind a layman's tag when it suits you not to answer a question, and yet come out from behind it to disagree with me. Read back through these posts, you will find that I do know the difference between speed and velocity. You may be making that remark based on the observation that I sometimes use the word speed, and at other times use the word velocity. Sometimes they are interchangeable, sometimes they are not. |
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#561
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From Wikipedia: Quote:
Here's another, simpler page that be at more your level: Quote:
Last edited by ZenBeam; 05-20-2012 at 02:27 PM. |
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#562
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I have just got to say that the difference between RFRs and IFRs has never been so well explained before. I have two years of college physics under my belt, but it was a while ago. Thanks to naita for pointing out that radial velocity is what Doppler shifting is all about, even in RFRs. I made a remark about a month ago regarding my enjoyment of the thread and I have since kept pace reading along. Let's see if I have my facts straight:
I am on track here? |
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#563
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Yes. As viewed from any IFR the fringe pattern is the result of a difference in path length. As viewd from the RFR the fringe pattern is the result of a difference in the speed of light. |
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#564
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Moving at 3e8 m/s 40 ps apart we get a wavelength of 0.012 m as you correctly put in your formula. I don't know where you get 0.003 M (and the symbol for meters is m, not M.), unless it's how far the waves move in 100 ps. Moving at 2e8, we get l = v*t = 2e8*40e-12 = 0.008 m. Again it looks like you've calculated how far they travel in 100ps, but you've kept the wavelength from the first situation, which is wrong. If the first wavecrest is reflected at t = 0, the second is reflected at t = 40 ps, the first wavecrest is then gets a head start of 0.008 m, which is the wavelength. Using this correct wavelength in f= v/l, we get f = 2e8/0.008 = 25 GHz . |
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#565
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TV Signal
Hi, I'm new to this board and this thread caught my attention.
I haven't read every page and this may have already been talked about, what if the space ship traveling to a distant star was receiving a television signal from Earth. The space ship is on a launch pad and has a TV set with a signal from mission control. The astronauts are seeing on the TV everything in real time and it's normal. The space ship blasts off and starts accelerating away from Earth. As they accelerate does the action on the TV slow down? Since the signal is traveling at the speed of light and they are accelerating to a speed that is only 98% of the speed of light, then they will never pass the signal. I know that it would take a very powerful signal to reach the space ship but, let's say it is powerful enough. Would the action on the TV slow down the faster the ship goes? When the ship starts slowing down, would the action on the TV start speeding back up? When the ship returns to Earth would the action on the TV start going really fast the closer they get to Earth? Like I said, I'm sorry if this has already been discussed. It just popped into my brain and I just had to ask. |
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#566
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You can simplify this by considering the case where the travellers are just looking at the earth through an incredibly powerful telescope.
Just by moving away from the Earth you are getting a steadily increasing delay in your visual impression of happenings on Earth, in effect a slowing down of the observed action. And yes, the faster you move the slower the action. Slowing down will speed it up until it's back to normal when you're at rest relative to the Earth. Moving towards the Earth the action will speed up, but the speed of the action will depend on the speed of the spaceship relative to Earth, not the distance. At very high speed the colour will be off, while if you stick to the TV-example you need to keep adjusting the frequency. |
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#567
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It'll be a bit more complex than just the action slowing down.
First, the carrier frequency that the TV signal is being transmitted on will shift. As the ship accelerates, the signal coming from Earth will appear to the people on the ship to be blue-shifted, with the signal apparently decreasing in frequency. On the other hand, as they approach the speed of light, time dilation will cause the people on the ship to experience time more slowly than those on the ground, which will make it seem like the signal is increasing in frequency to the people on the ship. I'm not sure which of these effects will dominate over which range of speed. In either case, the ship's receiver will need to adjust what frequency it is listening for the signal on, as they apparent frequency in the reference frame of the ship shifts. Secondly, the amount of time it takes for one frame of the TV signal to be transmitted will change. If the TV signal is being transmitted as a plain old analog TV signal, the TV on the ship will very quickly be unable to interpret the signal at all - analog TV signals require fixed timing of various parts of the signal in relation to each other, if time is passing at different rates at the transmitter and receiver the signal will be unintelligible. If we assume the receiver is capable of handling the frequency shift, and is smart enough to deal with the timing shifts in the transmitted signal, then yes, the action will seem to slow down or speed up, as it will take more or less time to transmit each frame of video. |
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#568
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Thanks for the replies. I thought that the action would slow down the faster that the ship traveled away from Earth.
Both replies I read just confirmed it for me. I didn't say it in my post, but I was thinking that the TV would have to automatically adjust since the frequencies would change the faster the ship went. Thanks again. |
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#569
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Actually, no. From the perspective of Earth, time is flowing more slowly on the ship. But from the perspective of the ship, time is flowing more slowly on Earth. As the ship approaches light speed, the frequency of the signal from Earth will continue to drop (assuming that the ship's thrust is kept low enough to minimize the time dilation from the acceleration itself).
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#570
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By the "clock paradox," if I fly out into space, very fast, and then turn around and return, a large amount of time may have elapsed on earth. I might only age 20 years, but come back to earth and find that they're celebrating the year 2550 (the twenty-fourth-and-a-half century!)
If my receiver was any good, I'd have centuries of old tv shows archived on my ship's computer. And I thought it was hard keeping up with my soaps as it was! |
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#571
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#572
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I should have included this in my last posting. I agree with you on your point that A and B are not moving WRT each other, and I have always held that position. This is from an earlier posting :- “The radar pulse is c relative to an IFR, not to the Earth. According to relativity the target is moving in a non linear fashion relative to that IFR, and is therefore moving away from or towards the radar pulse.”
I actually made two mistakes. One which I made in that reply and did not spot until after I had posted it was that I had used the outbound wavelength for calculating the reflected frequency. The mistake which I knew I had made after reading your posting was in using the conveyor belt analogy. If a conveyor belt running at 1 M/s is loaded with packages every 100 milliseconds, they will be on the belt at 0.1M intervals. This corresponds to :- F = V / W = 1 / 0.1 = 10 If the belt is speeded up to 2 M/s, the packages will still be at 0.1M intervals, but will now pass a particular point every 50 ms :- F = V / W = 2 / 0.1 V = 20 : The frequency has doubled., while the wavelength has stayed the same. However, this is not the correct way to look at light. This is a more correct analogy. That conveyor belt running at 1 M/s is feeding another belt which is running at 2 M/s. The packages drop off belt 1 and onto belt 2 (this corresponds to the radar being reflected and changing speed). As the packages transfer onto belt 2, they still drop onto it at 100ms intervals, but as the belt has moved 0.2 M in that time, they are now spaced apart 0.2 M. This corresponds to :- F = V / W = 2 / 0.2 = 10 . The frequency has not changed, the wavelength has changed. I got that wrong, and I do admit my mistakes. Well done to you, naita. You just worked at it, using maths and logic, and did not resort to a smear campaign or personal attacks as some (most) people on this forum have done. The upshot of this is that although the frequency does not change with the change of speed when light/radar changes direction from E to W or vice-versa, the wavelength does change. I will look into that to see if it throws up any anomalies. I was hoping to be able to bring this to a conclusion without needing to set up a new experiment to prove it. That goal is eluding me. One way to prove whether relativity is correct or not, is to make into a reality the Wiki setup of splitting a light beam and sending it around the globe. This does not have to be done at the equator, any line of latitude will do. It can be done near the north or south pole, with a length of fibre optic cable running round it to form a ring laser. Lay the fibre optic cable in a circle of 10 Km radius centred on the pole. This marks out a line of latitude which is 62,840 M long and rotates in 24 hours, so the speed is around 5e-5 radians per second (or 0.7273 M/s radial velocity) which is well within the operational capability of a ring laser. Split a pulse of light and send it round the loop in opposite directions. If the pulses appear back at the entry/exit point together, relativity is wrong. |
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#573
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Here is your big break. Take a tape measure or any other measuring device, and measure the distance form London to Bath. Wait a day or a year or however long you like, and measure again. Barring tectonic plate movements, the measured distance will not have changed. It will be the same whenever you measure it. Report back to this forum what change in distance you have found, and what the relative speed/velocity is between London and Bath.
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#574
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In physics, "velocity" is a vector. It has a magnitude, and a direction.
Since London and Bath are moving around the earth's axis, the direction of their motion is constantly changing. (Yes, it is always to the "east," but....) Their velocities are changing with respect to each other, also, for the same reason. An object in a circular orbit never gets any closer or farther away from its primary, but it is still always *moving* with respect to its primary. |
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#575
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#578
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Actually it does, but the difference between the two wavelengths is very difficult to measure. I am trying to find a way to amplify that difference.
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Using the setup I described (setting up a ring laser round the pole), you would expect the ring laser to show rotation then. |
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#579
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I'm no physicist, but I drop in on this thread once every few months or so just to see where it's going.
May I threadshit? I'll put it in a spoiler for those who don't want to see it. SPOILER:
Last edited by Senegoid; 06-13-2012 at 05:36 PM. Reason: minor wording clarifications |
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You all seem to think that I had made up my mind long ago about everything that is going on in this forum. That is not so. When I started this discussion (or perhaps joined in), I did have one basic starting point, and that is that relativity is wrong, and local aether theory (or speed of light relative to the local gravitational field theory) is probably correct. I have not changed my mind on that, but through this discussion I have enlightened myself, and some of you, as to what actually is going on on our planet, and some of the ramifications of SRT.
For instance, I have not "finally realised I was wrong on frequency change with change of speed" Which Zenbeam posted. The wording "finally realised" is totally wrong and infers that this is a long held belief, which it is not. I opened up that subject not knowing any answers as I had never before asked the question. I had just assumed, as I suspect most of you had, that the speed of light in our atmosphere was c/n regardless of direction. Because of working through (sometimes tortuously) the questions and answers, and digging deeper than most people would do, and yes - playing Devil's Advocate, unforeseen answers came to the fore. As recently as May 17th, Trinopus was still of the opinion that the speed of light here on Earth is c ( c/n ) in any direction. Originally Posted by tomh4040 . . . If the radar increases its velocity . . . Trinopus reply "Isn't this the core of the issue? According to SR, this doesn't happen. It's also never been observed to happen." Have you learned something from this exchange Trinopus? |
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It took over two months and who knows how many posts for what's a very basic relationship. I stand by "finally realized".
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#585
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(Yes, I know, it changes velocity, by changing direction. But it doesn't increase velocity. That implies an increase in the absolute value of the magnitude of the vector.) On the Straight Dope, asking people, "Do you see my point now?" has been shown to be a really, really rotten debate technique. It's your duty to make your point clear, and to defend it when it is questioned. |
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#586
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SRT says that the speed of light is c relative to any and all IFRs. The Earth is not an IFR, it is an RFR. That is an acronym which I have coined to differentiate it from other non IFRs such as a linearly accelerated frame of reference or an AFR. Restricting our discussion to east west travel at the equator, in order for the speed of light to be c relative to an IFR, it cannot be c relative to the Earth, as the Earth is an RFR. Because of the rotation of the Earth, a light beam split and sent round the Earth in opposite directions will not arrive back at the starting (entry/exit) point together. The beam going west to east will have further to go than its counterpart sent east to west and therefore take longer. This is because relative to an IFR, the Earth has rotated while the beams were circumnavigating, so shortening the east to west path and lengthening the west to east path. That is how a ring laser works. That description is when looking from an IFR. Looking at what is happening from here on Earth, and making all measurements relative to the Earth, the beam of light traveling west to east has exactly the same distance to travel as the beam of light traveling east to west. As the east to west beam arrives back at the entry/exit point before the west to east beam, its speed was faster. There are therefore two speeds for light, with the caveat that we restrict our discussion to the equator. If you are still of the opinion that the speed of light is c on the Earth, then by definition it is c in an RFR. If light is c in one RFR, it must be c in all RFRs. It cannot be c in a rotating ring laser (which is an RFR while it is rotating), or the two beams would arrive back at the entry/exit point together whether the device was stationary or rotating. They arrive back together if the device is not rotating (when it is an IFR), they do not arrive back together if it is rotating (when it is an RFR). This is covered in the Wikipedia article already referenced on the subject, and is also agreed by your fellow relativists here on this forum, so you really are alone in this. Wiki quote “If a number of stations situated on the equator relay pulses to one another, will the time-keeping still match after the relay has circumnavigated the globe? One condition for handling the relay correctly is that the time it takes the signal to travel from one station to the next is taken into account each time. On a non-rotating planet that ensures fidelity: two time-disseminating relays, going full circle in opposite directions around the globe, will arrive at the originating station simultaneously. However, on a rotating planet, it must also be taken into account that the receiver moves during the transit time of the signal, shortening or lengthening the transit time compared to what it would be in the situation of a non-rotating planet.” From a fellow relativist :- Quote:
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#587
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I find some fundamental flaws in thought processes in this thread. If anything relativity really shows the problems of scientific observation than it does about reality.
In the example of a person traveling to a near star system at the speed of light and returning. The person will return as exactly aged as those that stayed on earth. However, on earth they could show a second instance of the astronaut to himself through a telescope at a younger age. He would be observing himself in space time and mathematically that is what a scientist would get on his calculations. The light reflected from the astronaut is just a hologram. Unfortunately Physics needs two things in which to observe events; matter as in machinery in which to collate information and light in which to observe (anything at a distance anyway) It cannot observe events other than that and is therefore limited in viewing reality. Any instance in the universe can be observed by infinite amounts of perspectives with different results and none gathering an idea of reality as it actually happens unless it reverse calculates to compensate for distance and speed of light. The problem is matter cannot travel at the speed of light unless it is in the form of energy which Einstein correctly postulates as E=MC2, So only light itself and its own speed can be used to correlate reality. |
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#588
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Often when a relativistic thought experiment is described to someone who is new to relativity, they object with something like "But that is just the light!" -- because it sounds like a sleight of hand, it sounds like we're saying because light has a transit time then that in itself is time dilation. It's not what relativity is, but that's how it often comes across. I remember being told about someone travelling faster than c and why it implies time travel: but it was a badly described example and just sounded like someone seeing a set of events that had already happened in reverse order -- that's not time travel -- and it therefore took me a while to grok the time travel case. But the important point is that light itself is not special here, c is. You could basically see relativity as space and time being warped to preserve the invariance of c in all reference frames. Quote:
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Light that simply goes east, then west again, is not affected by this effect. The Michelson Morley experiment does not show any difference in speed of light beams that go east then west again, as compared to light that goes west, then east again, or north, then south. The Earth is both an RFR and an IFR, depending on what you happen to be measuring. Quote:
This does not apply to Earth as an IFR. Light that is sent out in a straight line, and reflected back again in the same line, moves at exactly c. This supports Special Relativity. We are in agreement. The M/M experiment, conducted in an IFR, supports the Lorentz Transformations of Special Relativity. Time, Distance, and Energy are compressed. The moving astronaut ages more slowly than the stationary astronaut. The effect of a ring laser does not disprove any of this. So....what are we disagreeing about, exactly? |
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#591
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To begin with, let's have the astronaut move at .99c, rather than at the speed of light. Moving at 99% of the speed of light is possible (although hideously expensive!) for a physical object. Moving at the speed of light is believed to be impossible for a physical object. Now: he goes to Alpha Centauri and back. Say, 4.00 light years for convenience. It takes him 4.04 years, each way. By the Lorentz equations, he only ages about half a year on each leg of the trip, so after the eight year round trip, he's only aged one year. Now: exactly how do you propose that "they show a second instance of the astronaut to himself through a telescope at a younger age." I don't understand what you mean by this. Once he has returned, he isn't in space any longer, and so they can't "show" anything to him. He's here. When he is in space, yes, he can send pictures of himself back to earth. People on earth can send him pictures. They can send him pictures of New Year's Eve, 2013, 2014, 2015, 2016, etc. He is amazed, as these "years" seem to him to be a month and a half apart. He can't send a picture of himself to himself. The light waves of the tv transmission move faster than he is moving. He could send a messenger rocket to himself, but this would add additional complications; you'd have to calculate the speed of this messenger, and how it related to all the other frames of reference. It's pointlessly messy. Quote:
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What Relativity tells us is that events that may seem simultaneous in one frame of reference may seen non-simultaneous to another frame of reference. Quote:
You and I might be in the same place at a specific instant, but you're stationary, and I'm moving very, very fast. We're both watching two distant stars, which go supernova. You might see them both go supernova at the same instant; yet I might see one go supernova before the other one does. Neither of us is "wrong." Both of us are right. You see two events as simultaneous; I see them as sequential. That's the price of relativity. |
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I've never quite managed to understand this. I don't know if it has been demonstrated using proper mathematics, or if it is an appeal to the unknown, since there is no physical meaning to the "square root of a negative number." I've done a lot of Google searching on this, and haven't seen a solid explanation. (Meanwhile, you do have the possibility of time travel in Tipler machines and other extravagances. Fortunately, no one is likely to send a probe in a high-speed closed orbit around a gigantic, hyper-massive cylinder that is spinning at extremely high rates of revolution! Tipler, Penrose, Hawking, and others suggest that this could lead to time travel...but I think the experiment will never actually be performed!) |
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To make it easier, imagine a signal can be sent instantaneously. In the black frame, send a signal to the right. Now accelerate to the right until you're in the blue frame, and send a signal instantaneously to the left in that frame. It can get back to x = 0 in the black frame in the past, in that frame. If the signals could be sent FTL, but not instantaneously, that may mean you need to accelerate a lot to send signals into the past. It's not strictly true that FTL signals always allows sending a signal back in time. It requires there also to be no privileged reference frame*. For example, if the black frame were a privileged frame, and these FTL signals were always instantaneous in that frame no matter what frame the sender was in, you wouldn't be able send signals backwards in time. * Our physics doesn't have privileged frames, but it also doesn't have FTL signals. Last edited by ZenBeam; 07-01-2012 at 07:39 AM. |
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#594
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(I'm only participating in this thread because questions have been asked which I *do* know the answers to!) Oh, well... I guess I'll just brew up a nice cup of Thiotimoline tea... |
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#595
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Two spaceships zip past each other at 87%c relative speed. Ten minutes after, you (on spaceship A) decide to send an (instantaneous) message to spaceship B, because their left rear light is broken. On spaceship B, from your point of view, five minutes have elapsed since the meeting, due to time dilation (at 87%c, the Lorentz factor is about 2). So the instantaneous message arrives five minutes after the meeting on B. The return message is sent immediately ('Thx, fixed!'), and, since from their point of view, only 2.5 minutes have elapsed on your ship (since you are moving, relative to them, at 87%c and five minutes have elapsed on their on-board clock), the instantaneous message reaches you 2.5 minutes after the meeting, and 7.5 minutes before you ever sent the original message in the first place. Which you now don't need to, seeing as how they've long fixed their rear light.
See also the discussion under 'tachyonic antitelephone'. |
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#596
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"Because of the rotation of the Earth, a light beam split and sent round the Earth in opposite directions will not arrive back at the starting (entry/exit) point together. The beam going west to east will have further to go than its counterpart sent east to west and therefore take longer. This is because relative to an IFR, the Earth has rotated while the beams were circumnavigating, so shortening the east to west path and lengthening the west to east path. That is how a ring laser works." That was what you quoted and is OK so far. This is what you omitted, did you agree to this? "That description is when looking from an IFR. Looking at what is happening from here on Earth, and making all measurements relative to the Earth, the beam of light traveling west to east has exactly the same distance to travel as the beam of light traveling east to west. As the east to west beam arrives back at the entry/exit point before the west to east beam, its speed was faster. There are therefore two speeds for light, with the caveat that we restrict our discussion to the equator." Quote:
Velocity of light west to east (VLWE) = 299,792,019.2 M/s Velocity of light east to west (VLEW) = 299,792,946.8 M/s Quote:
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Please answer this question. We know that in a (rotating) ring laser the two beams have different speeds or they would arrive back together. What size does a ring laser have to be before it ceases to be an RFR and becomes an IFR so that the two beams of light sent round in opposite directions arrive back at the entry/exit point together? Quote:
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#597
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Ask a question, and the participants here will try to answer it. |
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#598
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Like John Cazale, you ask questions of others, then refuse to answer ones put directly to you. |
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