md65536

You could rig it so that the box does drag everything. For example, if you're using rockets for acceleration, you could attach additional rockets and time them to implement the action of the box. (Then, another mistake I made is to consider moving the box using Newtonian physics, but consider the contents using SR.) Thanks for the link. It's interesting to see how Einstein is able to think about all of this in such abstract ways, which I've never been able to do. I suppose that comes from understanding the the maths and their meaning.

Well it's a bit over my head. What is the force of time? Is it a force like other forces? Or is there a better name than "force"? How is time like a stream? Is that an analogy, or are you saying time has a material existence? "objects, could INCREASE some form of their lifespan, by employing fast moving information" -- Is this a conclusion based on accepted science, or based on your new ideas? Either way, how exactly does that work? "Harnessing information is like adding some form of mass." -- How much information adds how much mass, and how much lifetime does that add? Mine's not an authoritative opinion on this, but I think that you're wrong. Perhaps someone else can understand what you mean, but for me you'd have to dum it down a lot. But I don't encourage you to waste your time trying to convince me personally because I doubt I'll get it. Are you more interested in developing your ideas in agreement with mainstream science, or as an alternative to it? If the former, you might have to express it all using established terminology, theory, and math. If the latter you might need experimental evidence.

Yes, I certainly didn't consider all of the details. When I first wrote this, it was because I was wondering what would happen if you basically put an entire twin paradox experiment in a box and then accelerated the box to counteract one of the observer's acceleration. Then I drew some conclusions and posted without thinking it through fully. I think in the most basic case, you simply couldn't accelerate everything in a box at the same time according to all observers, and the results of the experiment would be different than without accelerating the box. Perhaps frame-dragging could be exploited to accelerate an experiment in a box and get identical results to the original experiment??? But then anyone experiencing proper acceleration in the original experiment would experience it in the modified experiment too.

Error in my previous post: The thing about "two" ranges is something about how the brain processes color, not how the eye senses it, as there are usually 4 different overlapping ranges detected by 3 types of cone and 1 type of rod cell in the eye.

Agreed. I suggest photons because it's the simplest form of information transfer that I'm aware of. If for example you instead consider information in the form of moving matter, then you can break it down into subparticles, velocities, temperature (with internal motion), etc. All of these things can carry additional information, which either complicates things, or can be misleading if you skip over it. Are you saying that all information ages, and is affected by time which can be dilated? If so, then what is the change in a photon as it leaves its source, and the same "aged" photon as it approaches its destination?

Well, to be pedantic, gravity is an outside force, so it remains at rest if the forces are in equilibrium. Also the lace's molecules aren't at rest; there are some materials that would naturally "untie themselves" or change shape over time. Also the human body is not at rest; heartbeat and breathing can cause significant movement. Also your office is likely not very still; vibration from nearby traffic and other things can have a measurable effect. I don't think these are answers (I think other things like friction and tension from the knot are bigger factors, so even if everything was perfectly at rest internal forces could still untie a knot???), just a critique of assumptions. Oh... so I think a serious answer might be that there are some knots whose tension keeps the knot tight, and others that pull the knot apart, and perhaps you're using the wrong kind of knot.

Well, the questions only make a little bit of sense depending on interpretation. The EM spectrum is a continuous range of wavelengths, and the sun emits EM radiation along a wide range including visible. So UV, IR, and visible aren't "different ways"; they're all light just at different wavelenths. Also, visible isn't "one of the waves" but a range of wavelengths. To the eye it could be considered two---I think---overlapping ranges that are responded to differently by 2 different types of cone in the eye. If you remove visible light then you'd see no light. However we can still detect other frequencies, eg. you can feel the warmth of sunlight on your skin. Different animals have different ranges of visible light and can see wavelengths that we can't. I think different people also have varying sensitivity to different wavelengths. I guess plants also have different light requirements, eg. shade vs. direct sunlight. I imagine at least some can survive on visible light alone. Apart from whether atoms could exist and what other physics wouldn't work, and imagining that everything is completely dark on all wavelengths, then I think the entire Earth would be molten as there would be no cooling of its surface through radiating energy into space, which is how its crust formed in the first place.

I think that by the end it's gone off into nonsense, and I think it does this perhaps because you've misapplied some general concepts to specific examples, and then generalizing from that to draw conclusions with no justification. Information does not need intelligence. Information transferred between intelligent entities obeys the same laws of physics as information transferred between anything else. I don't think abstraction is needed for intelligence, because it can be modelled with only what's concrete or real. Physics already deals with information (such as that carried by light, or measured as entropy) and the transfer or movement of information, without needing new physics for intelligent communication. I think it could be improved by removing outlandish claims, and going for depth rather than breadth. For example, starting perhaps with the paragraph "Consider two people...", rather than just jumping to new ideas, isolate exactly what information is being transferred (in the simplest form), and how existing theory describes that information transfer, and what is lacking in that description---or how a new description offers an improvement. By simplest I mean eg. "a light signal, or photon" rather than say "speech + movement of air molecules + vibration of eardrum + nerve signals etc".

No, they just need to be brought together. If they pass and touch, even if they have relative velocity, everyone will agree on the "touch event"; everyone will agree on the two observer's proper times (age) of the event. Edit: There is only one *essential* change of inertial frame in the twin paradox, and that's the one that happens when they're separated. Anyway, I think we're all now talking about slightly different setups. Not all of us are talking about the standard twin paradox. I think we all agree there's no physical paradox here.

"Everyone must agree" means everyone agrees that when R and E come together, E has aged 4 years and R has aged 2, as an example. It doesn't mean that everyone aged the same amount. Essentially it means, "Everyone may measure things differently, but everyone agrees on what anyone else measures." All the different measurements agree. Twin paradox is focused on because it's a very simple situation with a clear classically unintuitive effect. Oh wait... I reread this and I see what you're saying. Yes, in this version when they meet they'll have aged the same amount. In this version both E and R make symmetrical movements, according to an observer on Earth for example, just at different times. In this version both observers experience the same proper acceleration. Edit: But the velocities DO matter. In this version they age the same amount specifically because you made them travel at the same velocities for the same proper times. Also, the essential "paradox" is still there: With time dilation, each twin measures that the other is aging slower while moving, so how can they end up at the same age? The answer is "because of length contraction and relative simultaneity".

It turns out (as should have been expected) that if R remains at rest it ages LESS than E does. The way that I was getting R to age more, and it would be the same problem with getting E and R to age the same amount, is to try to force it so that "E spends t seconds moving away from R at a velocity of v, and then spends 14t seconds (for example when gamma=2) moving toward R at a velocity of -v" which is not possible in Euclidean geometry. The separation of a huge distance is important, and I'll try to explain why. The u-turn itself is not that important. For example, in the case where only R is accelerating: suppose instead of a u-turn that R decided to make a huge arc around E so that the turn was more of a triangle, or even a semicircle. That would take some time, and there could be relativistic effects to calculate, but it would not change the physics of separation or return trips. Or, say that R got 100 LY away, and then accelerated a thousand times back and forth in 1 second. There are a thousand HUGE changes in relative simultaneity with E, but they cancel each other out and in the end this addition only adds 1second*gamma to E's aging in the whole equation. The equations depend on v and t (and d)... what's important is how long an observer spends traveling at v. But v*t = d, so I might be tempted to say "Really it's all about distance!" And yes, distance is important because you can't spend a long time traveling at high velocity without an accumulation of distance. But why it's WRONG to think "it's all about distance" is that there are different ways to get to the same distance... different paths to take and different velocities, and so different proper times or even two paths with the same proper time at R but that will have different relative aging at E. If you know d and t at every step, you can work it out (as v can also be determined). If you know a and t at every step, you can work it out. But how you accelerate can be neglected. If you can accelerate from v to -v in 1 second, or if you can accelerate in one millionth of a second, the difference in aging of the other observer will differ by less than gamma*1 second. If you must take a thousand years to do a u-turn, you can take a snapshot of the experiment at the start of the u-turn, and a thousand years later, and (assuming the u-turn starts and ends at the same point) you can remove the aging of R and of E during the u-turn and it will work out the same as if there was an instantaneous u-turn. The effects of acceleration only matter during the u-turn, so you can choose to neglect that time with negligible effect on the experiment.

I've looked this up a couple times and never found anything. I know I've seen animations of deformed turning gears, sometime in the past, but can't find them now. (Not quite as popular as "me dancing to popular song" videos, for some reason.) Here's what I think: - It'll look spherical. - The surface will look deformed and stretched. If you're not looking from above its pole, the side that is turning toward you should look stretched, and the side that's turning away from you should look squished. So the whole surface should look like it's being pulled or scrunched toward the side that's rotating away from you. - I *think* it would look the same size??? This (skip to 5min mark): suggests that you would see a smaller portion of the surface than "usual", or is this only when the observer is moving, not just the sphere? This: (vs. a similar but non-relativistic: ) suggests the opposite. Hopefully someone can give better answers.

If the masses can be approximated by point masses then I defer to swansont's answer (yes). But suppose m1 is a 1kg point mass and m2 is 2 planets connected with a bar a few AUs apart. I think that if you start with m1 some astronomical distance away, and have m2 oriented so that one of the planets is closer (say with m1 at an angle of 45deg relative to the bar), then m1 will accelerate toward a point very near the center of mass of m2, but as m1 gets very close it will accelerate toward the nearer planet. So the path of m1 will curve.

A relativistic Doppler analysis will tell you what anyone sees. Sometimes that makes it a lot easier to understand and cleaner, sometimes it's harder and more of a mess (see my recent posts for examples!). But nothing's swept under the rug. The relativistic Doppler factor can be derived from the Lorentz factor just by including the travel time of light. It should not be surprising that everything is consistent, whatever variables you want to use.

At time t=0 everything was a singularity, right? Could there have been different states of that singularity, and would they have been ordered? Time is a metric, a measure of distance between events. You could conceivably have a system with different ordered states but no measure of time between the states. If you use the word "before" implying a measure of time, it doesn't make sense and you can't talk about "before the Big Bang". If you use it to mean only relative ordering, then it could make sense -- I don't know if it would apply to the Big Bang though. ??? You would be speaking about the ordering of different states that all happened at time t=0. An analogy: "A is before B in the alphabet" but it has nothing to do with time. It might make sense to speak of preconditions of the Big Bang??? but not a time between them.

Edit: I'm double-checking the math and I think I've made an error somewhere here... ---- Here's an outline of a thought experiment that shows that the effects of the twin paradox are not determined by who experiences proper acceleration. Start with a basic twin setup: Observer E stays on Earth, observer R is on a rocket that passes Earth at time 0, moves at a velocity of [math]v[/math] for a proper time of t, then turns around and returns at a rate of [math]-v[/math] for a time of t. R then has aged 2t while E has aged gamma*(2t), where gamma is the Lorentz factor. Only R experiences proper acceleration. Now modify the experiment so that R doesn't turn around. Instead, R keeps moving inertially for the full 2*t, but at time t it sees E instantaneously accelerate and approach at a relative closing velocity of [math]-v[/math]. E catches up to R at time 2t. In this version, only E has experienced proper acceleration during the experiment, but it still ages at a rate of gamma relative to R. What allows this is that the proper times of the two phases of the experiment aren't equal to each other for the accelerating twin, as it is in the usual twin setup. So, I haven't actually analysed this to show it's true. Is it intuitive enough to be certainly true? Edit: So I decided I'd better do the math and it's not working out, I think I'm forgetting about relative simultaneity or I'm using the wrong velocity... :S ---------------- I think I Gerry'd this up completely. Where's my (many) error??? I think I forgot to consider that in the second experiment, in E's frame the "last clock tick before instant acceleration" and "first clock tick after accel" are essentially simultaneous, but they're not simultaneous in R's frame. If R remains at rest I don't think there's any way to make E's clock tick relatively faster just with velocity, so I think the hypothesis is WRONG. ----------------- So I think the main mistake is thinking that if R sees E change its relative velocity halfway (for R) through the experiment, that E would take the same amount of time (in R's frame) to appear to catch up as it did to recede. In reality, E would be seen to accelerate after very little Earth time has passed, and it would appear to catch up in I think the same amount of E time (not Earth time, now!) appears to pass, which would happen in very very little R time. So R would see E aging less than itself in this experiment. Mythbusted! Sorry if anyone feels they wasted their time

Might be just BS: A sphere is one of the simplest shapes, where every point on its surface is equidistant to a particular point. If the universe had a definite center, and a shape, then "spherical" would be quite a simple shape. Planets etc. have a center of mass. A sphere is like... the best approximation of "flat" across the entire surface of a 3d shape, maybe??? Like... flat land is closer to a spherical Earth than are mountains. Gravity pulls things toward the center of mass, roughly, filling the valleys and tending toward a spherical shape as a stable shape. Same with water droplets: "mountains" have more surface area than flat land; surface tension also tends toward flatness as stable. It wasn't a point or dense ball that exploded in 3d space. Time and space didn't exist "before" the Big Bang into which it could explode. Is it okay to say that at time 0, the universe was 0-dimensional? There is a theory or speculation (I could look it up if anyone cares) that the universe wasn't 3-dimensional in its very early forms, but had fewer dimensions. BS again: I imagine a point, being split in 2 directions (everything expanding uniformly but in only 1 dimension). As soon as you can measure distance between anything, you can measure time. As you separate the matter of the universe along this line, maybe there's curvature or something that allows you to measure a straight-line distance between some pairs of points as shorter than along the curved 1-d line, and it is consistent so that you can treat it as an additional spatial dimension. Perhaps fractional dimensions can appear as an increasingly curved space until at some point it can be consistently measured as an additional dimension. Perhaps space (and/or time) on a large enough scale will appear increasingly curved until a 4th spatial dimension is measurable. This is how I currently envision the Big Bang. Obviously it doesn't make clear sense in my mind, and I don't know if there's any value in the description.

It's already been explained in the original thread I think that acceleration is not a part of the calculation. You already know v from gamma, you don't have to use acceleration for anything. Anyway, at Earth the distances between everyone is essentially zero. Any change in relative simultaneity at that length is zero. For example, it wouldn't make any difference if you had started B and C far apart and had them pass by Earth at time t=0 with no acceleration occurring near Earth. Similarly at the end they could pass Earth without ever stopping. As long as B and C move symmetrically and compare clocks at the same location, the clocks will mark the same time. Remember no one *measures* anyone else's clock running faster than their own (only slower in SR or absence of gravity), even if they see it. Going by what they measure, accounting for delay of light, B's measurement of A's advancement in age occurs during the change in relative simultaneity that happens when B changes inertial frames. Going by what they see, the asymmetry is: B sees A's clock running 13.9 times faster than its own, for a full year. It sees C's clock running 194 times faster than its own, but only for 1.88 days.

If you're calculating numbers, use math. I have no idea what results in your "should" conclusions, but that's the something that is wrong. From B's perspective, C is always aging slower than A. It catches up by "leaping forward" with a change in relative simultaneity when it turns around. This leap is not apparent to B, but is seen gradually as C closes the distance to B and appears to age quickly for a short period. Math: - Calculate velocity of B relative to A using the known Lorentz factor of 7. - Find velocity of C relative to B using composition of velocities. - Calc how much C appears to age according to B using relativistic Doppler equation. - Determine when C appears to turn around, using Doppler. - Add up the different amounts of C's aging that B sees (I think there are 3 different phases, each can use the Doppler equations). No, A and C don't behave the same in this example. IF B turns around and catches up to C without C ever turning around, then B will observe that C ages a lot more than B. But if this happens, B would spend a long time catching up to C, all the while C is appearing to age quicker. In your example where C turns around, it appears to age quickly for a very short period of time. Alright I got curious and did it quick and dirty. Pasting from spreadsheet and ignoring significant digits... (Also, I've been sloppy so I'll just say I'm using a symmetric configuration, where the velocity of O relative to P is the same as the velocity of P relative to O, and not worry about which is which. -- Sigh, so many little mistakes to fix...) gamma = 7 vBA = 0.9897433186 c, (velocity of B relative to A) by solving Lorentz factor for v vBC = 0.999946858 c using composition of velocities, where vCA = vBA The observed tick rate of a moving clock is given by the reciprocal of the Doppler factor, let's call this epsilon, where [math]\varepsilon = \sqrt{\frac{1-v_{BC}/c}{1+v_{BC}/c}}[/math] = 0.0051547761 On the way back, negate the velocity, which results in the reciprocal of epsilon. So the 3 phases: 1: B ages 1 year while C appears to age epsilon * 1 year = 0.0051547761 years. 2: B appears to travel at the same speed as C for some time, until C is seen to turn around. I'll skip this step for laziness. 3: B sees C age one year at an accelerated rate of 1/epsilon = 193.9948452238, so this happens while B ages 0.0051547761 years. From 3, we can calculate that phase 2 takes 1 - 0.0051547761 = 0.9948452239 years, during which C appears to age at the same rate as B. Adding up: B ages 1 + 0.9948452239 + 0.0051547761 = 2 years. C appears to age 0.0051547761 + 0.9948452239 + 1 = 2 years. Note: To double check, one should be able to calculate the time it takes light to travel from C's turnaround, to where it would intercept B, and you should find that it happens at 0.9948452239 along B's return journey. Note that when B turns around, C has only appeared to age 1.88 days, and remains .99 of a year behind B for most of the return trip. On the last 1.88 days of B's return trip, C appears to age a full year. --------- Now just for FUN, what does B see of A? There are only 2 phases, because A is never seen changing velocity. The reciprocal of the Doppler factor comes out to epsilon = 0.0717967697 Phase 1: epsilon * 1 year = 0.0717967697 years Phase 2: 1/epsilon * 1 year = 13.9282032303 years for a total of 14 years seen aging.

I think you're right... I think that distance is meaningless except as a measurement of relationships between events, which are separated by information traveling at c, and so any non-zero time could consistently be associated with a non-zero length, but I don't think it could be proven. I doubt that either of us are conveying meaning precisely enough to have a useful conversation though... :S

Agreed. And yes, before C turns around, it ages less than A as measured by B, because it is moving away at a greater relative velocity. But when C turns around, there is a change in relative simultaneity. As always, calculations using length contraction and time dilation and relative simultaneity work out the same as relativistic Doppler calculations, which work out as expected that symmetrical observers will see symmetrical things.

B observes C appear to age faster than A only while approaching, but this happens for a much shorter duration than C appears to recede. The answer is similar to the Doppler shift analysis of the twin paradox: http://math.ucr.edu/home/baez/physics/Relativity/SR/TwinParadox/twin_doppler.html With pictures: http://math.ucr.edu/home/baez/physics/Relativity/SR/TwinParadox/twin_vase.html 1. No, according to B at this point, C has aged even less than A. 3. When B reaches X, it has seen C appear to age VERY slowly, because C's clock is slowed and also there is an increasing delay in incoming light as the distance increases. B turns around and heads back to Earth. It observes that the outbound journey is (and appears) to take the same time on its own clocks. Due to the delay of light, C is not seen to reach its turnaround for some time. Thus B sees C appear to age very slowly for a very long time, then---I think---appear to age at a normal rate while B is returning to Earth but C still appears to be receding, and then after C appears to turn around it appears to age very quickly (faster than A) for a short time, eventually catching up to B at the same time they reach Earth. In a Doppler analysis, differing amounts of time a distant clock spends appearing to tick slow vs. fast make everything work out properly. In a Lorentz transformation or spacetime diagram analysis, changes in relative simultaneity make everything work out properly.

Sure, his proper velocity (http://en.wikipedia.org/wiki/Proper_velocity) is greater than c, but that's not faster than light (whose proper velocity is infinite). He's traveled 7 LY but his destination has aged 7 years. Functionally it is equivalent to slowing his own time (eg. being in stasis in sci-fi). You can travel great distances with little aging, but you can't do it faster than light.

He's traveled 7 LY of distance measured from Earth's frame, in 1 year measured from the ship's frame. How is that faster than light? How long did it take light to make the same journey? (Example answer: It took 7 years according to a clock on Earth, but the ship took over 7 years according to the same clock. Is there any clock which records the ship traveling faster than light? Or do you have to switch between clocks and frames in order to measure the ship differently than you measure light?) He's traveled less than 1 LY in 1 year, both measured from the ship. Light is faster according to the traveler. He's traveled 7 LY in a little over 7 years, according to Earth. Light is faster. According to anyone else's measurement: Light is faster.

This is a very important thing to consider in these types of puzzles. For example: A woman has two children. You figure out that at least one of them is a girl. You ask her what it's like having a daughter, and she tells you a funny story about her daughter. Now, you keep talking to her and you're able to figure out that this girl is the youngest child. What is the probability of both children being girls? Why is the answer...