Regarding the demon I implied, without clearly stating so, that it can be a being from another dimension in a way that it can observe this dimension without changing its state (as we do) and without necessarily our limitations of time. The same can be said for the imaginary supercomputer and that I believe would get away with most common paradoxes and limitations. For example the supercomputer wouldn't need to have memory for itself or the demon as those our out of the universe in question. This would of course imply that the demon could still not know everything in its own dimension so you somehow transfer the problem, but still strictly in the field cosmology as we mean and observe it the demon I believe could have full knowledge.
I am sure I would disagree with a lot of theoretical scientists but they would probably say that I am cheating by removing the demon from the universe (which probably I am a bit).
Originally Posted by C_ntua
But speaking of a First Cause, Yarin seems to have anticipated your point with the assertion that:
at least treating "space" to mean "space-time".Quote:
Originally Posted by Yarin
It's important to reinstate that a pulsating universe can never be proved. The laws of physics make it impossible for us to do so. We can only eventually one day observe a universe collapsing, but our calculations can only put us close to an eventual singularity.
(EDIT in the shape of a PS)
An analogy can be made (carefully) with the idea of self-awareness. The moment at which you gained your idea of Self. When was this exactly? You cannot ever measure it precisely. It is lost because your brain never registered the moment it turn that aspect on or it did so in a time where there were no active receptors to store it. And more importantly, was there ever a "You" before You?
Do not be tempted to gain refuge in future science. We may reach a moment when one day all answers to the mystery of self-awareness will be reached. But this is so only because we benefit from an advantaged observation. We can observe others. As if an observer in another universe could study us and our universe. But were you living all your life in isolation in a cave, you would in fact properly emulate our universe boundaries in terms of what knowledge you could gain of your self-awareness. Regardless if you lived 90 years or a billions years, you would only be able to contemplate that you had a beginning, not sure when or how, and there was no time before you.
I find this thread very interesting, since relativity has always been my favourite physics problem :D
I know that my knowledge is very limited (through I must admit to have been reading and thinking on this subject much), but nonetheless, I would like to share my understanding as a young person. I will purposedly be using "I know, I should" instead of "we know, we should". And I am sorry if I am ignorant.
The thing I know is that there are at least 4 dimensions. The first three are spatial and the other one is time, all four forming a space-time. As far as I know, I should be looking everywhere for patterns and common features, and generally try to treat everything in a uniform manner. If so, this means that I should not differentiate dimensions into spatial [x,y,z], time [t], and others like let's say atomic-level (or whatever I heard of) [w1,w2,w3] etc. These all dimensions have common properties, and the only difference is that I percieve them differently. I percieve them differently because, e.g., [x,y,z] change slower for objects which surround me than [t]. Light moves at zero speed in the 4-th dimension [t], but with maximum speed in [x,y,z], unlike me who move with almost maximum speed in [t] and almost zero speed in [x,y,z]. This makes me think to treat all dimensions in a uniform manner, no matter how many there are.
Now I would like to create a universe equation. I have several possibilities. The most obvious one for a human being like me is to associate the function's variable with [t]:
1. fy = f(t)
This function returns all particles (and so forth) and their coordinates at the specified time point. This is the most obvious one, because as the time elapses things move and interact.
2. fy = f(x)
This one does the same, except that it accepts x as an argument. It is pretty hard to visualise through.
3. fy = f(y,t)
Or any combination as above.
The problem with my approach is that it seems to be introducing a global reference point, meaning that relativity does not exist for God who knows this function.
Having defined a function, do I really need to simulate it? What would be that simulation?
I have a function y=x^3 and this function just exists - exists in theory. If I want to check what is the value at x = -1000, I do a substitution. If I want to check what is the value 2,3,n units before that x, I just do a substitution. And my understanding of a universe (which changes everyday...) is something like this. If I want to know what happened at t = <some_t>, I substitute and get all possible coordinates of all possible information. If I want to know what happened before big bang, I need to substitute [t] to the equation and I will get the result. So I did not have to simulate it in a continuous form from the beginning of f(-inf) at all. It just exists for me as y=x^3 does for x = -1000.
The problem with my understanding is that I do not know whether I introduce a global reference point or not. I do if I have a reference state, like f(0), but I do not if this function does not have a reference state like y=x^3 does not. However, the function itself is defined in some way, so some information is somewhat globally predefined. I could use infinite recursion, not introducing any state, but this one seems impossible because it would require continuous simulation from the beginning. In any case such my function would allow my universe to be non-circular (not a "pulsating universe" as somebody before said?), and could be either discrete or continuous.
In other words, I imagine that God invented such a function, together with perception and ability to differentiate time from space. I know it does not make much sense through... ;)
Hey, I was meant to be getting back to something constructive like reading
through a zillion pages of Linux documentation, and instead I'm dragged back into
metaphysical speculation and even G. O. D.?:rolleyes::)
Anyway, what I was saying is that IF the big bang theory is correct ( currently its
known as the Standard Model and all observational data is generally talked about
with reference to it e.g. the recent discovery that the expansion is continuing to
accelerate.) and if it reaches a good degree of precision they will have found the
reference frame in which an observer would be accelerating in sync with the general
expansion.There is only ONE reference frame in which this would be true in space and
This reference frame would thus be a kind of absolute frame of reference throughout
In a static universe no such reference would exist.
Whereas to talk about before the big bang or 'outside' the universe would be the realm of
metaphysics - it would be trying to talk about a 'different reality' entirely maybe.
For example 'before the big bang' would effectively be to talk about before or beyond
time which is the definition of 'eternity', and notions of non-existance as opposed to
existance which as Mario wrote also have parallels with our own individual lives.
As the Nasadiya Creation Hymn from the Rig Veda says ' who really knows?'.
(Not that I'm recommending the Rig Veda or anything, it's just one short interesting passage.)
Of course, the other Big Bang is Life itself.
And what life is, is still another really biggy science has yet to answer as well.
So we have 2 mysterious big bangs.
As for God, well, we all know he sits on a cloud in front of a control panel with thousands
of buttons,pulleys and levers and if we pray hard enough he will give us next weeks lottery
"That is what I would disagree with. In my understanding of relativistic space, there is nothing outside our universe,
nor was there ever anything outside of it. There was nothing here at all until the "explosion" of the cosmic egg. And
then there was only what was in the "sphere" of the expanding universe" - me
I should have been clearer. The only point was that there is nothing outside the universe as we know it,
and there was nothing here before the Big Bang in the form of spacetime as we know it. That was all in
relation to relativistic reference frames. I would imagine that the "cosmic egg" itself was here at least,
immediately before the Big Bang.
So not the first cause, just the origin of spacetime.
in the same way?
Also, we can measure accelerating forces, like we experience just standing here on the earth, or the centrifugal
forces of the rotating earth. But this in itself doesn't indicate motion (Einstein's Elevator and Newton's Bucket).
Some will argue that there is no physical test that you can perform to indicate whether your experienced effects
are due to acceleration through space or gravity. This has nothing to due with the likelyhood of one or the other
being correct, just that both are equally valid.
It's intrinsic to the big bang theory that you can model the Universe
and that observation can be married with theory.
So the field equations are used to form a mathematically non-extrapolated
4d Riemannian universe. This riemannian equation describes a reference frame
in which an observer is accelerating in sync with the expansion.
All I'm saying is that if it is true it can be modelled then it would represent
a default absolute in the sense that intelligent cosmologists all over the universe
should agree on this model and thus this reference frame. This follows directly as
a consequence of the theory.
And whereas the expansion is only apparent on the large scale such that, for example,
our local cluster of galaxies take part in the expansion as a group, I would agree
that as an actual absolute against which ALL motion could be referenced, things might be
Ok, that's interesting.
Would that also imply an absolute center of the universe?
Would such a space be non-isotropic?
Well its been a while since I looked at this stuff, and I'm certainly no
expert, so you're probably better off googling for the minutae.
I mean, I have always taken the text book line that there was no universally
agreeable reference frame up until reading your piece when this 'irritant' thought
entered, so I'm still wondering what it means exactly, if anything.
I would think in a closed system a reference that different parts of
the system can agree on would normally be an absolute for that system.
But it may be in this case that whereas there can be agreement on the
model/reference it has no use beyond that.
So its some kind of Non-absolute Absolute.
Any cosmologists about?:)
One thing I don't fully comprehend with relativity is why do we choose to consider space and time relative but not speed. For example, if I talk about curves in spacetime I am basically saying that it curves compared to an "imaginary" 3-dimensional space. When I say that two reference points will see a different sequence of events I am using an "imaginary" absolute time where I could take two snapshots that would be different. All I know really is that if you are in motion using the same measuring devices we will end up with different results. We assume that the measuring devices are not affected thus we need to change how we view space, speed and time but I don't comprehend why we cannot just say that the measuring devices function in a specific way, meaning that the speed of light is not constant in that sense. Then we can keep the space 3-dimensional as well as the time absolute which at least to me feels more solid as modelizing the world just because I can understand it better.
If the speed of light is not constant that means that other laws become relative in that sense. For example, if we measure the time using the frequency of atoms that would mean that motion affects their frequency or motion would affect electromagnetic waves, which is something that we say is not true. Yet mathematically speaking you can say it is if you were to keep time itself linear. The difference is really how you imagine it and for me it is easier to say that motion affects matter in a fundamental way rather than changing the way I view time and space.
I don't fully comprehend the rest of your reasoning and you may need to clarify.
Let me go to the twins paradox again. Let me change it saying that the twin returns to earth and he looks exactly the same as his brother (we cannot prove yet if this is true or not), but the atomic clock in his spaceship shows something different. The question is if time slowed down in which the answer would depends on what do you define as time. If it is related to aging then time didn't slow down. If it is how the atomic clock measured it would (according to SR). At the end of the day both have to do on the effect of acceleration in atoms which we have trouble measuring anyway according to the uncertainty principle. The assumption is that time affects all atoms the same way, since it affects the clock it would affect the body. But "time" is really an abstract idea and with SR it is even relative. So instead of saying that acceleration affects time and time affects the body, you can say that acceleration affects the body itself, every atom of the body. The same can be said for speed. Instead of saying that space contracts or expands you can say that matter went faster or slower and that is what is what I meant that speed is relative or "more" relative including the speed of light.
I am not implying that SR is wrong, even if you think of matter fundamentally changing still the end result is the same and the differences are between different frames. But it is just a matter of how we view time and space and I don't think we can view them differently as we "normally" do. So spacetime can have a mathematical meaning but it is really not space and time the way we imagine it and somehow "overriding" the terms of space and time creates more confusion.
On the other hand we can imagine a clock going slower or faster easily. The reason is that we envision time using an "imaginary and absolute" clock. If we were to view a clock going slower it would be slower compared to our imaginary clock. If now we take the faster clock it would go faster compared to the imaginary clock. In both cases we assume of course that the imaginary clock stays the same.
If we want to imagine one twin aging slower then we would need to take a snapshot from both. SR shows there is no simultaneity. Yet there is no other way imaging it. This implies again that time is not relative, not in the way we actually imagine it. That is also what I meant of the spacetime having curves as a curve by itself means nothing if you cannot compare it with a straight line. So we put the "real" spacetime in an imaginary space which is in its sense 3D space not being affected by motion. Now if we were to use pure Newtonian laws then it seems that we can imagine things as we describe them. Time is the same as our imaginary time and space is the same as our imaginary space. You can say that this is due to the complexity, but my point is that you there is a certain way you will imagine or modelize them. So instead of trying to make a complex model or a complex explanation on how space and time is we can just describe the laws in a more complex way. When you put everything together you still have the same result regardless the model chosen.
(I am not sure I make sense anymore...)
Ah, I see your point now.
Well, Special Relativity was the beginning of a "new wave" of science that will invariably make our universe harder and harder to understand. Possibly for the simple reason its just the way it really is. Our understand of that which surrounds us has no doubt reached a threshold in which it no longer needs to concern itself with basic explanations meant for a practical life. I know i'm stretching it because there's still many things we need to discover, but I think you get my meaning.
And that is; On our quest for knowledge of the Cosmos (all things that are, were, and will ever be, from the smallest to the largest) we obviously are overshooting our still young and undeveloped human brain cognitive capacities. Most of the modern science today needs to be explained in all manner of tropes (analogies, hyperbole, anthropomorphism, parables, paradoxes, etc). In fact many of the things we have discovered in the past have evolved themselves into radically more complex entities that are hard to understand in modern science. The atom is a notorious example. It's cloud-like shape has evolved from the simpler orbiting electron form, but we know that even that is a gross representation of an object we cannot comprehend in the physical reality we inhabit.
And let's not even get into quantum mechanics.
But the important thing to retain about the Twins Paradox and other similar constructs is that they aren't real science. They are Thought Experiments meant to expose a complex scientific concept that can only be fully understood in the closed world of mathematical calculations. Let me make this perfectly clear: The Twins Paradox is not science. It's a way to convey science. It opens the mind for initiates to the actual science that will take place in its only possible domain; mathematics. And it can often also help convey science to the untrained. For this reason, the Twins Paradox and other constructs are potentially ripe with... I wouldn't call it inaccuracy, but are clearly loose in the way they describe a concept that can only be described in a mathematical format.
A true representation of a superior intellect has always been in my mind that of a being capable of having full cognitive understanding of a physical reality that isn't in the same domain/dimension where his senses inhabit. In that regard, we humans are lesser beings. Mere nothings in our ability to perceive the physical reality of our universe. Mathematics have been our greatest achievement so far in that evolutionary process. But that stands to reason being us so young in the universe.