tar

Owl,

I think "outward" from the big bang, as if it was an explosion is not a correct way to look at it.

In some ways we are still "where" the big bang occurred.

And if you notice, the cosmic background radiation is out there in all directions, not just in one direction.

If there were such a center, away from which everything was moving, we could probably identify which direction that was. Things would look different if we looked "in" or "out" or "across". But since things look about the same in all directions (if we kind of ignore the MilkyWay), we are still "at" the site of the big bang.

Regards, TAR2

Owl,

But there is such a thing as conventions.

My favorite example being, that if a group of explorers and scientists, talking to each other, comparing notes and building together a model of the world, created a globe, a model of the world, but they where from an area of the world, below the equator, they probably would have put Antartica at the top, and the Earth would be spinning in the opposite direction as we conventionaly have it going. (I came to this example while teaching a copier repair class, standing in front of a copier I asked a student behind the copier "which way is shaft A spinning" he replied "clockwise" when those in front clearly saw it spinning counter-clockwise. I thought he was looking at the wrong shaft, and we argued a bit, 'til I walked around the back to see what he was looking at, and (duh) the correctly identified shaft, WAS spinning clockwise.)

Regards, TAR2

Which way does the Earth spin? The way that appears counter-clockwise from the top, and clockwise from the bottom, of course. You take time to determine such things, because you have to look at it from different places, and different times, and determine the thing that stays the same in all cases. That is what is objectively real. Then you agree on a conventional way to call this direction and you have to carry with you all the same rules and conventions, and base the understanding on the "same" real objective examples for the "way you call it" to have meaning.

Owl,

Maybe I am half on your team, half on SwansonT's.

I have always had a problem with discussions of the delta ts and delta t's and the u that appears when you think the t and the t' should equal out and they don't. One way to look at it, is that if you thought they should equal out, and they don't, you were wrong in the first place. What if you thought the t and t' were different in the first place. Then there is no u to have to figure.

Illustrated by Einstein's train example with the simultaneous lightning bolts hitting the front and back of the moving train, o and o' standing on ground and train, respectively, midpoint between the strikes. I already have both of them having seen both strikes, and the example has o' seeing the forward strike, before the trail end strike?

If strike B is going to take time to get to o', then its going to take twice as long to get to strike A, which means from the beginning the strikes were separated by a train length. In which case they were not similtaneous to begin with.

It seems to me that the example shifts meanings from the start to the middle. You can not say two events, separated in space are happening similtaneously, and then use this "universal" now to prove that the events are indeed not happening at the same time to experiencial observers.

Can you?

Regards, TAR2

light is going to take half a train to get to the middle of the train, whether it starts in the front or the back, or whether the train is moving forward or backward. How could the guy standing in the middle of the train see the one before the other?

Owl,

I was in the low 140s IQ wise when I was younger. Probably in the 120s or 130 now, have not been tested.

And I am with you in a lot of what you say. But on this relativity question, I have defected to the enemy.

Other 170s are on the case. And they have not ignored our concerns. They have figured them out.

Regards, TAR2

Janus,

I accept.

Regards, TAR2

Consider the notions abandoned.

Owl,

There may be some subtle, difficult to translate, but important differences to talk about here. I have read your posts carefully and some several times. I easily may be misunderstanding, and I have not read your thoughts, on threads other than the ones I post to.

There may be some areas we disagree on. And I restate similar ideas with some important distinctions that I think are pertinent. Not so much to prove that I don't understand, as to point out an area of disagreement.

I am also on the "twins" thread, in Physics/relativity and subjectivity/objectivity and the theory of relativity, and the Ontology of time. All having this in common. Our personal model of the world, is of the same world that everybody elses model is of. It is important for each of us to have a "correct" model, it is built into our nature, to feel good when we "get it" and get it right. And we have no hestitation in sharing our "correct" findings and discoveries with others.

However the search for the "correct" understanding is complicated by each of us holding our own "correct" model, that while it jives with reality, does not jive with somebody elses model in all cases.

Thus the power and draw of the special relativity, and the general relativity theories and the efforts to find the way the two domains complete each other in an overall theory that fits together seemlessly.

Here, outside of my floating my own concerns, with other people's models, including those of physicists, I have a pretty reasonable feeling that although I don't understand the equations and what they are saying and not saying, it is way more likely that "their" model is a correct model of reality, than is yours, or mine, alone. That is because they are addressing, and have been addressing the same reality that we are referring to, but have done it in a systematic, triple checked way, in concert with others with the same intent. For many years. Ideas that seemed reasonable, but did not hold up, under the strain of logic, precise definition and testing, were discarded. What remains is a vast body of work that not only fits reality, but fits the careful models of it that were built by others in the past.

If you and I say "time dilation" makes no sense, it is more likely that we "are not listening" to what they are saying, than it is that they are saying an incorrect thing. Hence the "strawman" that SwansonT brings up from time to time. We can't point to a misunderstanding of the theory, and say "there" you see where you are wrong.

I have to resign myself to the fact that I am not the first to look at this, not the only one to look at this, and certainly not the smartest to look at this. And the best train going to my destination, has already left the station. It is probably better to try and catch up, or take the next train, than to think the train is on the wrong track.

Regards, TAR2

SwansonT,

Well good point about sound not being a good analogy for light.

But because light is so much faster than sound, we can investigate sound "going" from one place to another.

Light on the other hand is so fast, we have no way to get where its going before it does. The only way we can measure it, is by sending it on an outing and back, and divide the time it took by 2. It has left our frame of reference and returned, by the time we have measured it. Perhaps multiple times if the mirror system is set up so.

Or I suppose its been done by polarizing light and splitting it and crossing the resulting beams and measuring the interference and such after one beam has taken a longer route.

In any case, you always have control over both ends of where the light started and where it ended. You know "which" peaks of which electric wave and which magnetic wave you are measuring.

Once you get to outer space, say Alpha Centuri, you have no way to "be" at both ends at the same time. You have to use historical info to "build" the distance, and the time it would take light to travel it, out of the results of previous experiments.

Once so carefully built, the objective distance, becomes a true thing, that will only vary with the motion of the repective stars. One can predict, from previous info, exactly where, in reference to us, Alpha Centuri will be in 5 years, as both stars continue on their course around the center of the MilkyWay, and know from this distance how long it would take for a projectile, traveling at .866 the speed of light to reach the star, "bounce" off of it, and return to the projected position of the Sun. If the resulting calculation yields 10.4 years, then that is how long the trip will take.

What has already been established as what must be the case, will not dissolve. The preferred frame of reference is the collective findings of all the measurements, and all the discoveries, and all the imaginary models of objective reality that we have been fitting together for 10s of thousands of years. That includes the effect that gravity and speed have on our perceptions of objective reality.

We still have the ability to construct a working model of objective reality from this preferred frame. That putting ourselves into another frame is froght with apparent difficulties is not surprising, since we have not had 10s of thousands of years to figure everything out, from there.

Regards, TAR2

Olvin,

I was wondering however, if something about what you are saying might be sensible. For instance, although there are galaxies of all different shapes, there do seem to be a number that are like the MilkyWay, sort of "flattened" out, with a bulge in the middle. And the voids of space, with strands of galaxies around them, sort of like the galaxies being the soap and water and the voids being the air in a bucket of suds. And the picture I remember of a simulated black hole, with high energy particles shooting out, top and bottom.

Not "agreeing" with your model. Just offering suggestions as to what I meant by "showing physicists where to look". Show how it explains something, that can be observed. (In all cases.)

Regards, TAR2

Janus,

The same number. Though the rate will vary as the trip progresses. At 0.866c, she will see the tick rate go from 3.73 the pulsar source rate to .5 as she's goes from Earth to midpoint and from .5 to 0.268 as she travels from midpoint to Alpha C. Even located at 10,000 light years perpendicular to the flight path there will be a Doppler shift effect.

If she sees half or a quarter of the pulses, in half the time (having only experienced 5 years during the 10 year trip,) how does that add up to the same number of pulses?

Vilas,

I am not doubting the physics, or the math.

I guess I am a lousy teammate, 'cause I will probably leave you hanging on a few of your points.

I think they are correct when they say we are doing ourselves a disservice by not doing the math.

But I am not sure.

I do still hang on to common sense, at the same time as I accept the observations, and continue to look for, and ask for the explanations that do not require me to do partial differential equations. I am not sure that this means I can never see it correctly. Perhaps it does. But considering that I have already philosophically come to the understanding that my model, is just that, a model, I am hoping that I can readily incorporate anything that is found to be true into it with ease.

Even though my model includes matter that is made up of tiny atoms and particles so that I know everything I am looking at is mostly empty space, I still pretty much ignore that fact, and pour my soda into a glass, with the understanding, that none-the-less, the soda won't leak though the spaces.

Regards, TAR2

Besides, reality was still real for everybody that lived in the 19th century. And they did OK without knowing they were taking a geodesic path. In fact, I have no reason to believe that Maxwell didn't know. He just didn't describe it that way.

Sure we have discovered a lot in the last 150 years, and sure, it was done primarily by people that could do the math. But that does not mean I cannot comprehend their discoveries. And it does not mean that I cannot question something that does not make sense to me.

"photon lag" puts what is currently happening on Alpha Centuri forever 4.5 years from us ever knowing.

I say, according to my model, that the background microwave radiation, redshifted 1000 times, showing us that portion of the universe that at the time of the photon release was in a universe that had just become transparent, is now a portion of the universe that has had 13.7billion years to evolve and may be sort of like here and now, with galaxies and strings of galaxies. I don't think I am countering observation or physics to come to that conclusion. Just using common sense.

Janus,

Or are you saying she sees it pulsing twice as fast, in half the time?

Regards, TAR2

Janus,

Would that also mean the frequency of light she saw it pulsing in would be double what we see it pulsing in?

Regards, TAR2

Owl,

I believe there to be a few problems with "All the universe happening now".

For instance, if that was true yesterday, what is true today?

Or, which "now" are you considering happening "now" on Alpha Centuri?

Problem with, or perhaps the nature of, the universe is that it does not all arrive everywhere at the same time.

I have no problem with considering everything happening "now", from a God's eye view, that is not constrained by the speed of light, but that is an imaginary condition. Possibly a "true" way to view it, but the happenings in this "now" do not arrive here instantly. 8 minutes for happenings at the Sun, 4.5 years for those on Alpha Centuri, hundreds of thousands of years for distant parts of the Milkyway and so on.

And you can never "get to" those other nows. You can only be at the one you are at.

There remains a slippery thing, even to consider one's own now, much less the translation to something light-years away.

For instance, what happened to my now, that I was experiencing 2 hrs. ago at work. It is no longer present here and now. However somebody on Jupiter, or whatever platform is 2 lighthours from here, with a powerful telescope, trained on the building I work at, would see me outside, smoking, NOW!

So all the universe is not happening now. We can designate our now being shared immediately by every other point in the universe, and substract back and find out when that now will arrive here, and when our now will arrive there. But its a mental excercise, except for what we know had to have happened in retrospect. When we see light coming from the Sun, we know it had to have been shining 8 minutes ago, and when we see Alpha Centuri shining in the sky, we know it had to have been shining 4.5 years ago, but we have absolutely no way to see what it is doing now.

Unless of course if we consider, as far as we are concerned, what it is doing now, is what we see it doing.

These are the "two" nows I can count. The universal one we imagine, and the actual one we see.

And in actuality the universal now comes into our actual now, at various times, depending on the distance of the event.

But I do not believe you can call both types of now, by the same name, without keeping them as separate conceptions. One that you experience, and one that you imagine occurring.

Regards, TAR2

Ophiolite,

Thank you for your comment. It made me feel like I made a small contribution to the effort.

"By the way" my comment to Olvin, was also addressed to me. Too often I am in such a hurry to share an insight that I have had about the world, that I forget that other people, (in most if not all cases) have already had the insight, already shared the insight, and already "checked" it out against reality to see if it "holds" against it. If it does it is retained and new insights are built upon it. If it doesn't it is discarded.

What is difficult to know is "if" others have had an insight of yours. Even though the probability is that it has already been had, and most likely been had yesterday, last year, 20 years ago, hundreds or thousands of years ago, it still feels good to have a "new" (to you) insight, and the impulse to share it is strong.

Incumbent upon anybody therefore is to share your "new" insights with the world, but understand that, if true, they are most likely held by somebody already, and the sharing is a "teaching" about the world.

If "not true" they are an indication that you have something more to learn, and need to increase your knowledge, not only of the world, but of what others collectively have already determined about it.

Incumbent upon everybody is to know that the world is already true. Its ALWAYS our model of it that has room for additions and corrections.

Regards, TAR2

Chris,

Well, good point. The theory does explain "why" this happens. I yield (mostly.)

Would still like to know how many pulsar pulses she would count. According to the theory.

Regards, TAR2

Olvin,

Relaytons?

I read through your amended considerations. You "added' this particle to your model. I was having trouble with the "constan" arrangement. I don't know where to "put" these newly imagined particles within the "constan" arrangement. In fact, I did not know where to "put" mass in the "constan" arrangement.

Does mass displace constans in any given space (made up of these constans)? Or do the constans continue to exists, touching each other, thoughout the mass (which would tend to "push apart" the mass, if that where to be indeed what constans did to mass). In either case there seems to be a problem, because we have to wind up with reality, if the explanation is to be of it. And what particles is this mass made up of?

Relaytons smell like epicycles to me.

Regards, TAR2

By the way, I am not a physicist, just a layman, that "uses" the facts about the universe that physicist have discovered. I do not think that physicists would have any reason yet, to "look at" your theory, team together and study its implications and so on, because it is not complete, not consistent, and does not "explain" anything that isn't already being looked at and is not already, in great detail, described and studied and agreed upon, to be true. It is not anybody elses job to repair your model, but yours.

Remember, a physicist has no way to test your model in your mind. They can only test it where you tell them to look for it in reality. But first you have to find it there. Reality is not required to fit your model. Your model is required to fit reality.

Regards, TAR2

Chris,

Well OK, this happens. I do not doubt the findings. But WHY the muons act in this way is still open to wondering. After all, this shortening/dilation that the muon experiences would be experienced by ANYTHING and EVERYTHING coming into the Earth with the same direction, speed and mass. The objective conditions of the test site, remain.

Regards, TAR2

Cap'n Refsmmat,

But you can put yourself in the shoes of the oblate sphereoid pilot, do a loop-de-loop and come by the Earth again from a 90 degree different direction, and find it still an oblate spheroid, but squished the OTHER way.

You would immediately know the squishing was due to your speed and direction, land and find the Earth a sphere. Would you not?

The idea of relativity did not arise with Albert. We have been putting ourselves in other people's shoes and walking around stuff to understand its nature, since we starting remembering and predicting stuff.

The whole idea of "objective reality" is based on our comparision of our current point of view with another point of view, and taking what remains unchanged, as real. Individuals can do this by themselves by moving around in space and seeing what "always seems to be the case". Or simply wait a moment...then compare what you remember to what you are experiencing. Or check with someone or something else an see if something is true for them too. Or imagine yourself in the shoes of another established true entity and imagine if they would also find this thing true. Or make up an entity, give it as many "true" characteristics as you can remember, and pretend it was experiencing reality, imagine what you think it would experience, and then test it out "for real" and see if it indeed is the case.

We all have found that we exist in an objectively true world. And we ourselves are objectively true to our neighbors.

Regards, TAR

Mathematics is not symbols. Neither is mathematics primarily equations or even solutions to equations. Mathematics is not only describable in words, it is in fact described in words -- see any good mathematics text. The symbols are merely shorthand for a great many words. Those words are important The use of words in mathematics is exquisitely precise, and you need to know what they mean.

DrRocket,

Thank you much for post 117.

I am on this talk board for a dual purpose and this serves them both well.

One is to test my model of the world against reality and the findings of others (and adjust my model accordingly.)

The other purpose is to investigate language, and the meaning behind the words.

To these dual purposes, I will float this;

Math is precise shorthand for a great many words and words in turn are themselves shorthand for a great many meanings. Front and back (the words) have some portion of analogous meaning to +1 + (-1). But let the subject be a woman... and various interpretations are possible in either English or Math when the two terms are used. Futher clarification of what one "means" may be required. Hence the rules and grammar and the "long forms" that more precisely describe which meanings were meant by the statement.

But the communication of meaning, is done between two minds that know the same shorthand, and go by the same rules.

Which brings us to "that which is meant".

Vilas and I have limited knowledge of the shorthand of physics.

We do however have full access to reality through our senses, and have each "noticed" the order of things, and have an analogous model of it, resident in our brains. Our models do not "fit" reality exactly. We don't have all the info. But then again we have a lot of info, and the info fits together.

We can throw and catch a ball, drive our cars around turns on highways, and do all sorts of calculations and manipulations and predictions and interactions of and with reality, without even once knowing how to solve a partial differential equation. (and maybe Vilas even DOES know how to solve such a thing)

Insights that I have had, that are new to me, I later learn have already been had by other minds. And those minds have no doubt progressed to further insights. Difficult to know what insights another mind holds, if you yourself have not had them. But "insights" implies to me, that I have noticed something new about the world, that improves my model of it. The actual world has not changed a wit. (till I "do" something about it)

With these twins, we are discussing a few things, comparing models, attempting to see what the other "means" by time dilation, length contraction, speed and position. The actual universe stays the same and fits together the way it fits together.

Regards, TAR2

Owl,

But this is not to deny that now is the present both here an on the sun... and throughout the universe.

Well as long as you differentiate between the universe's now, and an observer's now.

The entire observable universe is visible "now" from an observer's point of view. But not in its universal now state. The universal now state can only be imagined to exist. But it (the universal now) can be reasoned to exist, because we have experiential proof, that an earlier observer's now (yesterday) coincided with an earlier universal now, by witnessing the arrival of images of the events that occurred one lightday away, in yesterday's universal now.

The trick (which I am still working on) is to advance ones own now, at the same rate as one advances the universal now, and factor in the distance/time between events that occur in the universal now, that show up here and now with various delays, depending on their distance. (Events happening in the Universal now, today, on the other side of the Milky Way, won't show up here for 100,000 years.) (And we consider the Milky Way our "home" and "nearby" galaxies our neighbors, as if we could run over and borrow a cup of sugar.)

The stars we see in the sky are "present". They were there yesterday, and will be there tomorrow. We can count on them. They exist in our reality, in just the condition we see them in. But from our observer point of view, our here and now.

Regards, TAR2

J.C. MacSwell,

Well thankyou for understanding what I meant by what I said. I was trying to figure out how to defend my statement against SwansonT's harse criticism.

Yes, I think there is time dilation. Yes I believe relativity is the proper way to look at reality.

I was merely investigating what that means to things, in terms of their relative age, and considering the idea that since the universe has shown its ability to keep exact account of itself, there maybe a "conservation of age" type of thing that the universe does.

I was sort of drawing an analogy to the other "balancing" things the universe does. That the universe always is balancing the checkbook, at every point, all the time, without error. Take heat for instance, always finding ways to even out.

Time dilation in the analogy would be like talking about things being hot or cold. A system would have an average age as a system would have an average temperature. And perhaps in the analogy, the age of the universe is the age of each of its grains added together and divided by the number of grains you are considering.

I have not tried out this analogy for but 24hrs or so, so I am not sure whether to consider slow, hot or cold.

That is, if tickers should influence neighboring tickers, would time flow from fast to slow, or slow to fast.

For instance, is a particle in an accelerator being "refrigerated" or "cooked"? Would mass be an insulator from, or a conductor of age?

Sorry, my analogy, my job to see if there is anyway it could hold.

Overall point being that C is the invariant, but space and time are not arbitrary, they are characterisics of the real arrangement of real particles and fields, and each particle and its position has to "fit" the scheme.

If A is related to B then B is related to A in the opposite manner. If A ticks faster than B then B ticks slower than A. But the distinction makes no sense unless you consider a time period in which A accumulates more ticks than B. Can't go by A's clock, can't go by B's clock. Have to go by C's. (no pun intended)

So let's take a pulsar, 10 thousand light years exactly, from both the sun and Alpha Centuri, that lies on a perpendicular that bisects the path her ship is taking. How many pulses will she count on her trip, compared to the pulses counted by her stay at home twin?

Regards, TAR

Swansont,

OK then. Back to the twins. There are assumptions made and frames switched all along the way, and certain SR effects and GR effects that are confounded, depending on your "starting" point in each consideration.

In many cases, as with the cesium clocks that have moved at different velocities, all the clocks, whether they are going up or coming down, moving with or against the spin of the Earth, or staying at the airport are constantly under the combined effects of the rest of the universe, with which they "need" to stay in tune.

It struck me in your response to my hydrogen absorbtion line question, that "assuming the hydrogen in the Earth and Sun STARTED at the same age" is not necessarily a correct assumption. The "path" that each particle, that created each hydrogen atom, and the subsequent path each hydrogen atom took to get from the Big Bang, to our solar system, define a different history. Almost impossible to consider the "actual" age of each sub component, from any given starting point, considering that the starting assumed age may be incorrect. There does seem to be however, ways that the universe balances things out, as in the SR and GR equations, where something can only be given up here, if it is gained over there. The total age of the universe will be conserved. None of the universe should be able to get too far ahead, or fall too far behind, because each part is affected by and conversly affects, the rest of it, at the speed of light.

When we pick a frame and consider all points starting at the same age in the same place, the assumption is not completely correct. The stuff at one end of the frame, is at a different place than the stuff at the other end. The math gets incredibily complex. The universe however, can figure it out, in an instant and know exactly how to behave, considering ALL the "effects" of motion, ALL the time.

I believe my problem with the twins is that I can not conceive of the travelling twin actually leaving the universe, and becoming 5 years younger than ALL of it. I would think that inorder to make the trip, she would have to take a substantial part of the universe with her. Considering how much energy it takes to get a tiny particle up to relativistic speeds, she would have to rearrange a lot of the local universe, to get herself and her ship up to that speed. And the universe would find a way to balance things out, so that she would not fall substantially behind.

Regards, TAR2

Swansont,

I am sometimes perplexed by the nature of experiments designed to test, say gravitational redshift, in that the setup is complex and many assumptions are made, where it is hard to know what is being already taken into account and what has possibly been overlooked, when there seems to be simple experiments that would do the same job. For instance, wouldn't the Sun provide a sufficient enough gravity well, that we could consider that the adherence of nature to the scheme of general relitivity would cause clocks on Earth to tick faster than at the sun, measure a hydrogen absorption line from some Earthly hydrogen, compare it to the same hydrogen absorption line from some solar hydrogen, and say "There." "See the difference?" "That proves that hydrogen ticks faster out here, than it does deep in the Sun's well". "And look!" "It fits the formulae exactly!"

Regards, TAR2

But wait. Wouldn't that mean that the hydrogen on Earth is "older" than the hydrogen at the Sun?

And if we calculate the age of the universe, should we go by age of the Earth's hydrogen, or by the age of the Sun's hydrogen?

Dr Rocket and Swansont,

I truely do yield to the logic and thouroughness that scientists and mathematicians have used to discover stuff about our world and our universe. And I have always found logic and completeness in the explanations and formulae "once I understand what they mean."

But not having a complete understanding of the steps, and the explorations built on established findings, built on previous explorations and established finding, I sort of have to take the journey again, myself, insight by insight, to get to the same place as I would be if I just "accepted" the findings.

Its not that I don't trust science, or that I do not realize that the sensible thing to do, is to yield to the many more agile minds, that have in concert investigated and documented their findings and reviewed the findings of others to assure the "reality" of what is "known" to be objective reality and its nature.

But what it is, is a desire to be part of the investigation. To add something. To "check" if an insight I have come to, has already been had or not. If it has already been noticed, fine. I just need to be told. If I am wrong about something, I might need some reasoning as to why I am wrong.

I often seem to "not get" what is considered "proof" of something. Some obvious things to me are "not scientifically" proven, and some "scientifically" proven things seem fanciful and unreal to me.

I have a general inability to discern when something is a questioning of somebody else answer, and when something is an answer to somebody elses question.

For instance I always thought that E=MCsquared WAS an answer to what the universe was about...till I read about this or that person's "solution" of Einstein's field equations.

How do you know when an equation is a statement of fact, and when its a question, that needs to be answered?

If E=MCsquared is a statement of fact, can't you just express it in real units, and do some algebra and substitutions and express anything involving energy, in terms of mass time and distance. Anything involving mass in terms of energy time and distance, anything involving time, in terms of energy, mass and distance, and anything involving distance in terms of energy, mass and time?

If E=MCsquared is a question, what is it asking that we don't already know the answer to?

Regards, TAR

I guess my mind is neither agile enough nor educated enough to get it.

I have read various descriptions and attempted to understand various formulae and always there are assumptions made that leave out realities that I have determined through the understand of other discoveries, need to be the case.

Perhaps I would be satisfied with my stupidity and ignorance if everything that Physicists said, actually made sense.

Most of it does, but some of it is contradictory, and thats where I draw the line.

I guess comprehending a vast universe and ones place in it, and ones relationship to it is in the end, a subjective, personal thing. My model does not have to satisfy anybody but me. It just has to be internally consistent, and fit reality.

For instance black holes that deform spacetime to such an extent that nothing, not even light can escape.

And this is proven by the discovery of structures that EMIT high energy radiation?

Swansont,

I agree, that Physics is a discovery of the Physics of the universe.

There are problems determining both the position and change in position over time, of an object, from the contradictory perspectives of two observers who themselves are changing their positions over time, in respect to each other and perhaps the object in question. But Vilas's and my contention is that the object must obey the laws of physics, and each observer must obey the laws of physics.

If the laws of Physics have predicted that light will take 4.5 years to get to Alpha Centuri, then an object traveling at .88C will take 5.114 years to get there. Whatever the traveler sees in her rear view mirror and through her windshield (gamma ray shield?) will conform to the physical laws of the universe. She cannot measure her progress through an already established distance at a speed greater than C. She will measure her speed at .88C, or else she has violated reality, or made a mistake. She in my imagination, will age right along with the rest of the universe, because she never leaves it. If we on Earth watch her on the trip out, she will appear to us as a redish or infrared or microwave image, and she will appear to be waving to us in slow motion and her trip out will appear to us to take a good portion of the 10.2 year round trip. But on the way back she will appear as a blueish or ultraviolet or x-ray image and appear to be waving at us at a fast rate, and we will time her trip back at only a couple years, or whatever the remainder of the 10.2 years is left, once we see her turn around.

Although see appears to us to be aging very slowly on the way out, and very quickly on the way back, she did 5 years worth of aging on the way out, and 5 years worth on the way back. If we count her waves, there will be 5 years worth on the way out, and 5 years worth on the way back. If she left here 27 years old, the immigration officer on Alpha Centuri will confirm her to be 32 and when she returns, our scientists will confirm she is 37.

The wierd thing happens when we observe the Centurian immigration officer signing the 32 year old's papers when we, (her twin) are 36.5 years old. But then again, not so weird, since we know it took the image 4.5 years to get to us.

Seems to all add up to me. Don't know where the laws of the universe say that she should return younger than her twin. That, in my imagination would break the laws.

Regards, TAR2

Swansont,

Not sure what your point is.

Physics is a human invention. A description of the rules and laws that the universe goes by, according to our view, and to increase our understanding, and give us the ability to predict what will happen if we move around in it and manipulate it. So we can know what will work and what will not.

The Physics of the universe don't have a point of view. Not any. Not a preferred frame or a unliked frame. No frame at all. You have to refer to it, to have a frame.

Regards, TAR2

md65536,

I don't see the problem. I fully agree that our present is not the same present as any other place and time. This is probably the basis of relativity. A fact that can not be ignored, and should not be ignored. Light takes time to get around. But it is also the case that starlight enters our eyes, and reports to us the "presence" of said star. We have to admit that the star is real, and existant in the universe. It therefore must have existed to emit the photons, however long ago it took for the photons to get here. The "long ago" assumes a hypothetical, imaginary consideration, that a "now" that is not dependent on light to report its presence, but that can be "figured out", exists concurrently at my eye, and at every other "place" in the universe, that has exactly the same amount of history from the big bang that my eye has.

Us actually experiencing the events that are occuring "now" everywhere else in the universe, depends on their distance from us. What is happening at the other side of the room will reach me in nanoseconds, what is happening at your location will reach me in less than a second, what is happening at the Sun will reach me in 7

minutes, what is happening at Alpha Centuri will reach me in 4.5 years.

So what is happening similtaneously to my now, is every other positions "now". At every place in the universe, there exists "age of the universe" worth of history, "age of the universe" worth of photon emmission and reception, "age of the universe" worth of evolution of particle development and decay. And in a nanosecond, every location will experience a "new" moment, in which their location is "age of the universe"+1 nanosecond, which, as soon as the nanosecond passes, is the new "age of the universe".

What is difficult is to "know" this is the case, and never being able to "see" it. Light is too slow, to allow us to ever experience the entire universe, in this "now" condition.

In fact, we can only experience our own now, ever. That this is everything elses now as well, is a fact that we can only share in thought. We can never actually share the moment...till later...in retrospect.

So this universal now, has no practical importance, but to visualize the stage upon which we are set. And to comprehend the nature of that which we experience, and that which the "stuff" that makes us up, has experienced in the last 13.7 billion years.

What is nice about the arrangement, is that we get to actually see in the sky, what stuff was doing in the past, and by analogy can study our stuffs history. Close stuff, our recent history, and far away stuff our distant past.

But the separation, in time and distance, between ourselves and the rest of the universe's "now" is both real and immense. On the other hand, our involvement with all of the observable universe is immediate, because we experience it in our very real now. AND this input from the rest of the universe has been going on continually, since the universe became transparent. So we have had a constant historical connection, with it all.

Which now one talks about can vary. Whose shoes, when, are you putting yourself in the shoes of?

For instance, one has to define the collective observers you are lumping together, and the grain size of the moment you are considering, as in "now" meaning the early 21st century for Earthlings.

I think where you get in trouble is thinking that past present and future define the same subsets, from both our now, and the universal now. This is not the case. Remember, what we figure to be, is not the same as what we experience.

We always experience our present. We always remember our past and we always predict our future.

A different place experiencing our universal now, is what will actually appear in our future. And anything we actually see represents what was going on there, in one of our past universal nows.

There is no actual platform from which one can actually experience the universal now. (Other than human imagination).

Regards, TAR2