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In reply to an earlier post on Jul 10, 2012 7:12:34 AM PDT
Matt,

<<- `do I really see anything ever `come out of a "future"' >>

Imagine we are playing a game of tic-tac-toe. I'm X and you're O.

X _ O
_ _ _
X _ _

is the current position. It's your turn. What are you going to do?

Because there is a future, you are obligated to put your O between my two X's, or else you will lose. That is, the future has reached back into the present, and via "backwards causality", affected (determined) what you are going to do now. You see what is "going to happen", and so do I. My future actions have restricted your present options. How does this happen, unless you are assuming it's existence?

So, yes, I do see things 'come out of a future'. Every day, at every instance. Our actions will have consequences, but only in the future. All my present actions are designed to be consistent with futures that I think will be desirable.

<< -do I ever see anything sinking into a past >>

The reason you have to play the obvious move is that there is a history to the game. That history includes my two X's being aligned in a certain way. That history is what determined your future, and the future consequences have determined your present.

Because there is a future and a history, I know that you are going to lose this game of tic-tac-toe--provided you keep playing.

X _ O
O _ _
X _ _

X _ O
O _ _
X _ X

and you resign, because you can see that you are in a no-win situation. You lost it on your first move.

In reply to an earlier post on Jul 10, 2012 8:45:00 AM PDT
I propose we give horse his very own button: "Horse? Do you like this person? Yes or no?"

In reply to an earlier post on Jul 10, 2012 9:03:21 AM PDT
Nova137 says:
rofl!

In reply to an earlier post on Jul 10, 2012 9:26:20 AM PDT
Nova137 says:
M: Sounds very interesting, especially 'if time travel is possible, time itself is not." , I`d like to understand the reasoning that gets to this particular, seemingly, contradictory point. - I`ll check out the link, thanks.
N: The time in question is the kind we all come to feel physically. It is an arrow that starts at our birth and ends upon our death. Its direction is in one direction, to wit, from the moment of our birth to the moment of our death. There is no reversing it or going back upon it. So, the apparent contradiction is cleared up when we consider the irreversibility or reversibility of time's arrow. There can be no arrow if we can go back upon it (reverse it). No arrow is being equated, then, with no time.

M: The essence of my point is that many people seem to start discussing 'time' in great detail, without first checking that what they think they are talking about really checks out. So I`m never surprised when a contradiction arises, in fact I think they are inevitable especially if people discuss 'the past' or 'future' without checking they can prove these 'things' exist.
N: This is circular reasoning isn't it? How does one first check that these things exist so that they can prove that they exist?! In any formal system, one cannot prove the axioms are consistent from within the system. Does this apply to subjective experiences as well? What say ye?

In reply to an earlier post on Jul 10, 2012 10:46:24 AM PDT
NH,

I agree completely with that assessment. Barbour is doing the right thing by exploring these possible extrapolations of physics in the quest for simplification. The thing is, it may be possible to pare down our set of required assumptions in this way. It is an interesting question what the minimal set might look like.

But I am under the impression that reality may be describable by many qualitatively different sets of axioms, subject to various possible measures of their simplicity. For example, let's take a question like "What determines the value of pi?" On one level, the decimal representation seems hopelessly complex, an infinite train of "random" digits that admit to no sensible pattern. But on the other hand, there are all these cool formulas that seem quite orderly and predictable, and enable us to precisely predict the "randomness" that at first seems so intractable. Why should such a common, simple idea be so involved, in decimal format? This was where we stood for quite a long part of history.

But along came Wallis, who showed that:

A)
pi/2 = 2/1*2/3 * 4/3*4/5 * 6/5*6/7 * ... ;
= INFINITE PRODUCT of ((2n/(2n-1)) * (2n/(2n+1))) ;

Historically, let's imagine we are at the point where we only know of the Wallis formula
Would we be inclined to say that this is the "reason" the decimal expansion has the value it does? We very well might.

But now, run the clock ahead, and we find that ALSO,
B)
pi = 4/1 - 4/3 + 4/5 - 4/7 + 4/9 - 4/11 + ... ;

Is this ALSO the explanation of pi's value? Moving on, we might discover that

C)
pi^2/6 = 1/1^2 + 1/2^2 + 1/3^2 + 1/4^2 + ... ;

Now we have three potential explanations for pi's decimal value. They are obviously different formulas with differing mechanics, different operations, and so on. Some of us might say that A) is simplest, since it only has one type of operation. Others might prefer B), because addition is more fundamental than multiplication--which is repeated addition. Still others might like c), because you don't even have to subtract, or because the denominator pattern is just counting. Simplicity is in the eye of the beholder, it seems.

But to me, the real confusing question is, Are they all "the" explanation? Is there a "THE" explanation, at all? That is, are we chasing rainbows when we seek to discover "The TOE", as if there was only going to be one of them!

(WIKI lists maybe 100 or so different ways to get to pi. They come in flocks that have certain similarities within that flock, but the flocks are quite distinct. Some formulas look very orderly, whereas others are full of arbitrary constants that defy easy comprehension.)

In QM, we have a similar sort of situation. We have this theory that works very well at a calculational level. But it doesn't seem to make a lot of sense, so we struggle to develop these "interpretations" of the theory. The idea is, I guess, to find "THE" interpretation that explains the theory's gears and workings in a way that seems satisfactory to humans. Currently, there are at least 14 or 15 different types of interpretations that are apparently logically consistent with the theory. Is one of them going to be "correct", and all the others, "incorrect"? I doubt it. I think these are all like the formulas for pi, above. There are many ways to skin Schrodinger's cat.

In reply to an earlier post on Jul 10, 2012 12:14:40 PM PDT
nope, i noticed this '0 out of 1 people' thing a lot but just thought it might be some Amazon forum coding bug and couldn't be bothered to mention it. Who's doing it, it's not me, is it you?

In reply to an earlier post on Jul 10, 2012 12:31:05 PM PDT
It's horse. It's about all he can do, given that his interface is apparently a cell phone--and not one with an alphanumeric keypad, at that.

In reply to an earlier post on Jul 10, 2012 1:12:56 PM PDT
John Donohue says:
>>Jody R. Bailey says:

G'day w,

Is that true?

I haven't heard that gravity affects an instrument as vaguely precise as a clock.<<

Indeed it does -- and for gps the accuracy needed to get the error down to a few meters requires the correction for both the relative speed of the satellite compared to ground stations (makes satellite clocks run slower) and the lower gravitational force felt by the satellites (makes satellite clocks run faster). The calculation, simplified for us less skilled physics mavens, is presented in Exploring Black Holes: Introduction to General Relativity by J.A. Wheeler.

In reply to an earlier post on Jul 10, 2012 2:12:19 PM PDT
Someone don't like you very much. But it's not me. I never vote one way or the other.

If Einstein himself posted something on relativity, e.g., I'm quite sure I know of at least 2 morons who would vote him down immediately.

In reply to an earlier post on Jul 11, 2012 8:30:09 AM PDT
Nova137 says:
Randall,

I'm reading this material covered in this link http://en.wikipedia.org/wiki/Quantum_field_theory and some of the material from the links within it. Aside from getting a little dizzy in the head ("and I'm feeling blue"), I'm charging along digesting what I can. The following caught my eye toward my sense a reconciliation isn't necessary (or even possible):

"Observed physical phenomena can be described well by quantum mechanics or general relativity, without needing both. This can be thought of as due to an extreme separation of mass scales at which they are important. Quantum effects are usually important only for the "very small", that is, for objects no larger than typical molecules. General relativistic effects, on the other hand, show up mainly for the "very large" bodies such as collapsed stars. (Planets' gravitational fields, as of 2011, are well-described by linearized gravity except for Mercury's perihelion precession; so strong-field effects-any effects of gravity beyond lowest nonvanishing order in φ/c2-have not been observed even in the gravitational fields of planets and main sequence stars). There is a lack of experimental evidence relating to quantum gravity, and classical physics adequately describes the observed effects of gravity over a range of 50 orders of magnitude of mass, i.e., for masses of objects from about 10−23 to 1030 kg."
From http://en.wikipedia.org/wiki/Quantum_gravity

In reply to an earlier post on Jul 11, 2012 8:45:34 AM PDT
Last edited by the author on Jul 11, 2012 9:00:23 AM PDT
I think these are all like the formulas for pi, above. There are many ways to skin Schrodinger's cat.
-----------------
I agree. In fact, the more I look into different QM interpretations, the more I realize that they are (almost) isomorphic. They give very different meanings to humans, but until QM theory is found to be incomplete, or we find a new measurement, none can be distinguished from the other. That in itself is reason to not create metaphysics based on only one, if your metaphysics is contradicted by the others.

If relational methods for deriving GR and time are found to explain more with less, our minds will consider it a more fundamental theory. It isn't clear yet if this will happen.

In reply to an earlier post on Jul 11, 2012 10:01:59 AM PDT
Right. The logical extension of this quote is that a theory of quantum gravity is only necessary under those very extreme and unusual situations where there is so much energy/mass packed into such a small area that gravity cannot be ignored on the microscopic scale. This basically only happens in 2 situations: inside a black hole, and during the very first moments of the Big Bang.

In reply to an earlier post on Jul 11, 2012 10:09:34 AM PDT
Nova137 says:
The wiki article mentions those two extremes specifically, yes. Those will be difficult to measure. hehe. I wonder if Randall will provide some insights into why we need to keep going. He has some interesting angles on these things.

In reply to an earlier post on Jul 11, 2012 10:24:33 AM PDT
Because they're there?

In reply to an earlier post on Jul 11, 2012 10:41:09 AM PDT
Nova137 says:
This is why we would keep going?

In reply to an earlier post on Jul 11, 2012 11:29:12 AM PDT
Well, it worked for Hilary (the mountain climber, that is).

In reply to an earlier post on Jul 11, 2012 1:12:40 PM PDT
Last edited by the author on Jul 11, 2012 1:26:40 PM PDT
Nova,
These extremes are where all the "theoretical action" is, so to speak. Our two main theories certainly produce predictions (in their respective domains) that are accurate to within the limits of our ability to measure. However, it seems clear that GR has a theoretical issue that QFT is not known to suffer from--at least, QFT doesn't suffer from it any more, since Feynman (et al.) developed the 'renormalization' procedures.

This class of mathematical techniques enabled QFT to overcome the rampant plague of infinities that bedeviled it, early on. In the case of GR, it is pretty obvious that these techniques will not work--at least, not in the same way--and no one has figured out how to get GR not to produce infinities in these extreme cases. (There are a few 'ad hoc' possible fixes, but they feel like they're not in the spirit of the basic theory.) On the other side, QFT makes one startlingly bad prediction about the vacuum energy (cosmological constant) that is off by at least 40 orders of magnitude! (This has to be some kind of record, worthy of the Guinness Book, I think.) So, while it may be quite accurate for it's comfort zone, that zone is not as big as we might hope.

I would point out that there are other places where these to domains come together, or at least within spitting distance. One place is in the GPS satellites, which have atomic clocks described by QFT, but orbiting in a low-gravity field, and at sufficient speeds to require relativistic treatment of their interface with earthbound components of the system. Also, workers at the LHC must "where different hats", as they perform their researches.

Another is in the fine-tuned version of QM called "relativistic QFT", developed in large part by Dirac. Only by making relativist corrections to QFT equations can the much touted accuracy of these calculations be achieved. So far, only special relativity plays much of a roll in this hybrid theory, since masses and energies are still quite low, compared with what goes on in black holes & big bangs.

The thing is, these other examples are getting close to the point where a full, consistent theory that uses (or models) the principles of both QFT & GR may be a technological necessity in the near future. If, for instance, the LHC manages to produce mini-holes, as some suspect it might, then these creatures will need some theoretical description that we haven't exactly got 'on the shelf'. I think the particle physics community feels this heat rather palpably, at this point. And they understand what strange bedfellows GR and QFT are, and how uncomfortable their marriage looks from our present POV.

Both GR & QFT are like the jealous god of Abraham, in that they each demand that the universe adhere to their respective rules, totally and without compromise. QFT demands that the universe is entirely quantum in nature, and GR demands that it isn't quantum at all! GR demands that the universe have no fixed "background" of time & space coordinates, and QFT says, "What? Are you nuts?" GR sets a specific restriction on c, more or less by definition. But QFT allows (nay, requires) photons to go at any speed at all, and maybe all of them at the same time!

It's as if God had published another set of tablets that had a sarcastic "...NOT!" at the end of each commandment, and gave Moses both sets to bring back down the mountain. The resulting confusion among the people would be a lot like what is now going on in the upper echelons of theoretical physics.

We could get into an interesting discussion about the specifics of these conflicting commandments, and why they oppose each other. But it might get awfully technical awfully fast.

In reply to an earlier post on Jul 11, 2012 1:20:25 PM PDT
"Both GR & QFT are like the jealous god of Abraham."

Now I understand why I've been wandering in the wilderness of confusion for 40 years trying to understand them!

In reply to an earlier post on Jul 11, 2012 1:56:38 PM PDT
Nova137 says:
I believe the order of magnitude is actually 120!

In reply to an earlier post on Jul 11, 2012 1:58:29 PM PDT
Nova137 says:
"Also, workers at the LHC must "where different hats", as they perform their researches."

Explain.

In reply to an earlier post on Jul 11, 2012 2:41:22 PM PDT
Under QED alone, that is true. But the more general 'umbrella' theory of QFT, which includes QCD (quarks & gluons), gives a refined result. Of course, the ridiculous accuracy which is attributed to quantum predictions of things like the fine structure constant are performed in QED, exclusively. QCD has yet to approach anything near this precision, but apparently, it isn't off by 120 or 122 zeros, when you figure out the vacuum energy. Only 40. That's like a factor of 10^80th improvement! So, I guess we're making progress. As Obama says, "We have more work to do."

In reply to an earlier post on Jul 11, 2012 3:15:30 PM PDT
I mean they must alternately make their sacrifices to the two different 'godheads' of QM & GR, depending on the task at hand. I'm not sure, but my (so far shallow) exploration of the Higgs mechanism looks like there might be some GR-based corrections to the mass estimates involved. In which case, this would be another area where QM & GR collide. Also, it might account for why all these theoretical mass estimates are so vague. If any lighting strikes me, I'll let you know.

The Higgs mechanism (and again, I warn you, I'm probably talking thru my hat) is largely a creature of Supersymmetric Supergravity, which is an attempt to rationalize the two 'godheads' into one (much larger) symmetry group that would include gravitons (and thus, gravity) as a quantum field. The 'super' prefix used to be commonly attached to "string theory", as well, since the strings are supposed to be "supersymmetric superstrings", technically. But I think physicists got bored with sticking "super" onto every noun in every sentence they had to speak, so now it's just tacitly assumed.

Nota bene that--as of now--the Standard Model does not include gravitons, and thus, cannot unify the "four forces" of old. (Nowadays, it isn't so accurate to count the forces this way, BTW. Gravity, under GR, isn't a "force" at all, but rather, a byproduct of geometry. And in QFT, what used to be counted separately as EM and Weak, are now seen as one composite force, with strong implications that the Strong Force--aka, "Color force"--may soon be brought into the fold.)

In reply to an earlier post on Jul 11, 2012 3:20:30 PM PDT
Jeff Marzano says:
N. Hunt says:

[That in itself is reason to not create metaphysics based on only one, if your metaphysics is contradicted by the others.]

Do you mean that QM theory is metaphysical ?

Jeff Marzano

In reply to an earlier post on Jul 11, 2012 3:29:18 PM PDT
Last edited by the author on Jul 11, 2012 3:32:25 PM PDT
BTW, that was another area where the GR & QM world views are in stark contrast. GR says gravity is the geometry of space-time made manifest; a "false force", like the so-called "centrifugal force". QFT says that if there's a unification to be made, then this must be another force, proper, complete with a boson and everything. It stops looking like pure geometry, at that point. Gravitons would be detectable things (in principle), like photons are. They would be responsible for deflecting the paths of objects in a newly flattened space-time, presumably, just as photons don't seem to require curved space-time to do their thing. [Or perhaps the space-time is overall flat in the large, but really twisted up good at the scale of Calabi-Yau manifolds in all those extra dimensions.]

In reply to an earlier post on Jul 11, 2012 3:40:06 PM PDT
they are all crude approximations
first order simulation models

none of them are right

we have a long way to go
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