Spacetime; Why it exists. Why it must.

Dear fellows;
I strongly believe that that space and time are inexorably linked due to the fact that if the Universe wasn't expanding outward (foward in all directions ). Time would not exist. For without movement linear or not we would not have spacetime. They cannot be separated. Movement brings forth time as we understand it.

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Machiaventa Mechezeldeck

 

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Motion requiring time doesn't mean motion creates time. A car needs fuel, that doesn't mean it is the reason oil exists. Motion is something moving through space-time, it is defined in terms of space and time. That doesn't mean it creates them and even if it did you don't explain anything, you just shift the burden of explanation from space-time to motion except now you have something whose very definition requires a different concept, space-time. Why should there be motion? Why should there be space-time? For example, if we can construct a reasonable physical model for dynamical systems which doesn't require a notion of space-time then we've broken away from the "For dynamics you need space-time" assumption you're implicitly using.

Numerous attempts at constructing physical models within theoretical physics have made considerable headway in this regard. Loop quantum gravity doesn't start with the notion of space-time, it builds it. Non-geometric flux compactifications in string theory give rise to a well defined notion of space-time topological structure and string dynamics but without the notion of locations.

Taken to a bit of an interpretive extreme such quantum gravity models imply that gravitons, particles of gravity, form space-time as some kind of enormous ensemble of particles. The particles don't exist at some set of locations in space-time, they ARE space-time. Of course the very concept of having position and time created from some more fundamental construct is pretty mind warping but it illustrates how naive intuition based reasoning is quickly can fall on its face when confronted with the most universally fundamental problems.

 

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If you were born in space traveling at near light speed on a starship what time would be used to say when you were born and where?

 

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That doesn't tell us why either one or both exists. And, it's existence or non-existence is relative to what can observe and/or interact within that spacetime.

Lastly, the very word "exists' is a relative term. Something can both exist and not exist at the same time, depending on what can or cannot interact with it.

 

Whatever the clock you had with you said the time was, and wherever you were in relation to everything else. It's all relative, remember? Alternatively, you can just get into a big argument about it when you get back to Earth.

Regarding location in particular, if you visited the room in the hospital where your mother gave birth to you, although that is where you were born in relation to other nearby objects, it isn't the same location in space. This is true even if you happen to be there when Earth is at the precise same point in its orbit, because our solar system, and even our galaxy, is always moving too. So in a sense, the problem of exactly "where" you were born is always there anyway.

 

"Forward In Time"

machiventa, the arrow-of-time = forward-in-time ergo Fullers comments, that, "we cannot return to the womb".

If spacetime = gravity and if gravitational spacetime membrane/web is the fundamental essence of Universe, then we must ask ourselves whether gravity, like energy/physical, exists eternally i.e. energy cannot be created nor destroyed so can we assume the same of gravitational spacetime?

Yes, if not more so. Some believe there was a beginning to energy/physical Universe aka a vacumn fluctuation called the big bang.

First of all there never was a true vacumn. imho The essential, quasi-physical/quasi-energy gravitational spacetime membrane/web exists eternally as a finite volume of occupied space, within a macro-micro infinite non-occupied space that embraces the finite gravitational membrane/web.

Quasi-physical gravitational spacetime membrane/web may have, at worse or best, led to creation of physical/energy.


___________________
___________________


_______________________membrane quasi-physical
VVVVVVVVVVVVVVVVVVVVVV energy
-------------------------------- membrane quasi-physical

1) energy/physical aka observed motion may exist as--- or because of --the inbetweeness two planar membranes,

2)or within one tubular membrane

3) or between two( or more ) tangentally interfering, tubular membranes of gravitational spacetime.

I recall Lee Smolin's comments of a spaceship in a vacumn, that begins moving will produce EMRadiation, and specifically states not from the fuel or engines, to clarify what he is saying. That may be in his book Life of the Cosmos.

As for those born at speed-of-light, well there is no time because there is no relativity at speed-of-radiation, constant to all frequencies of radiation or nearly a constant according to Lee Smolins Loop Quantum Gravity proposals. Of course the experiments did not confirm LQG and that may be because we are not looking at ultra-micro scales of EMRadiation frequencies, yet.

I don't think we ever will. I'm also skeptical of Smolins claims--- some 13 years ago ---that humans will quantify gravity via some gometrical method within 15 years. That prediction is in one or two years from now.

r6

 

Space and time are reference variables which allow us to define how the tangible variables relate and change. For example, we can collect a liquid in a beaker, or we can contain energy within an electric field. However, we cannot collect time in a bottle, because time is an abstraction that we can draw with math. We can draw a unicorn too. Space is the lack the substance or that exists between substance; space=nothing. How do you collect nothing?

A good analogy are directions on the compass; north, south, east and west. This is a convention of direction that we all agree upon, none of which are tangible in a physical way, but only in a mental/abstract way. I can't save all my wests for later, but use up all my norths, souths, and easts, until there is only one direction in the universe. The directions are not tangible, like a rock, but is simply a direction abstraction that is placed within the mind.

When space-time contracts, your mind is bending the relationships between tangible things. Picture if you had a camera on your head that shines out a coordinate system in laser red that stays center at one tree. But instead of a laser projector, it is done with a projection of the mind and allows us to reference how the tangible things appear to change.

As another analogy, we can normally use (x,y,z) to describe position in space. But say we used polar coordinates which measures position with the radial distance from the origin plus two angles. See Below. Would these angles be anything special in terms of reality? People may be tempted to equate these angles to spin of any kind, so it appears more than a reference.

Time and space is part of math reality, along with imaginary numbers.

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One would think pinpointing the precise coordinates you were born in the spacetime continuum would be the responsibility of the hospital where you were born. If they don't already have those records on file, they should be required to do so.

 

Need Details

Wellwish, I like this approach as we have a visual to work with and less of the complex abstract maths. I would like a better explanation of each of your symbols and what is being defined by those lines-of-relationship. I

Some might say that in going from Euclidean/planar to curved we induce the concept of spin. Also we know that the spherical cubo-octahedron's surface area is equal to the surface area of the 4 great/equlatorial circle planes that define it, however, in its Euclidan planar configuration, the surface area of the great/equlatorial planes do not equal the surface area of the cubo-octahedron.

Fuller points out, how when going from a the Euclidean/planar version of the subdivided icosa(20)hedron--- 120 right-triangles ---to a spherical subdivided icosa(20)hedron, there is 6 degrees of angular gain, in each of the 120 right-triangles ergo 120 * 6 = 720 degrees of gain i.e. the same as the total surface angle degrees of a tetrahedron.

see graphic 902.20 in following link

http://www.rwgrayprojects.com/synergetics/s09/p0000.html#902.01

r6

 

Speed is a relative concept, so saying "You were born in a craft moving close to light speed" is meaningless. Right now you, Buddha12, are moving close to light speed relative to cosmic rays moving through the solar system, do you notice anything? No, because speed a relative concept and your question implies some notion of absolute speed.

Why are you singling out imaginary numbers? The 'real numbers' are just as conceptual, the labels 'real' and 'imaginary' don't represent some measure of physical validity. All of mathematics is conceptual, abstract constructs within our minds based on logical formalisms and built upon selected axiomatic statements. When we do something like count 3 sheep or weigh 200 grams of flour or run 40 metres that doesn't imbue 3, 200 or 40 with some kind of valid physicality. Rather we are associating structures within Nature with abstract concepts. What is 3, the concept of 'three'? In formal mathematics it has a specific definition in terms of axiomatic constructs like the Peano axioms. In day to day experience we encounter/experience/acknowledge 3 cars or 3 seconds or 3 people and in each case we identify the 'three-ness' of these physical things, associating the things to the abstract concept of 'three'.

It's like mistaking a map for the place the map represents. If I count sheep and say "There are three sheep" then I'm associating the physical entities, the sheep, with an abstract concept of 'three-ness'. In this sense 'three' is the map, an artifical construct used to represent something physical, which would be the place in this map analogy.

Anyway, this is getting a little overly philosophical... A good rule of thumb is to never assume that when a common word is used in mathematical terminology that the mathematical meaning has anything to do with the usual meaning of the word. Real and imaginary are examples. Others include 'group'. If I say "There's a group of people over there" then in this context 'group' means a collection, for which the formal mathematical terminology would be a 'set', a collection of objects. To a mathematician a 'group' is a set endowed with a binary operation which obeys certain conditions. An example of a mathematical group is the integers (whole numbers, both positive and negative) under addition, in that add two integers gives an integer, there's some integer X which satisfies X+Y=Y for any Y (we usually call such an X 'zero'), for any Y there is always a Z such that Y+Z = 0 (we usually write Z as -Y in such cases) and (X+Y)+Z = X+(Y+Z) = X+Y+Z. The set is the integers and the group is a set where you can combine objects in the set together to get other objects in a particular way. A 'field' in mathematics is a group with even more properties, it doesn't mean a wide open space covered in grass.

Unfortunately this reuse of words for terminology regularly leads to confusion in non-mathematicians, particularly hacks who try to borrow terminology to make their nonsense look better but don't know the specific meanings.

They can only give the location in a particular choice of coordinates, other coordinates will give other location labels. Given the lack of an absolute reference frame in physics there isn't any way to do this absolutely anyway.

When talking about things which are counter intuitive or outside of personal experience mathematics isn't a burden, its a benefit as it allows you to be guided by sound logic and not dubious personal opinion.

The fact you're unfamiliar with the concept and notation of spherical coordinates suggests you don't have much, if any, experience with notions of space-time within physics and hence are in extreme danger of being guided by imprecise personal preferences, rather than logic.

Depends entirely what you mean by 'spin', as there are several similar but distinct notions of spin within physics. Particles can have spin within flat space-time while spin 0 particles in curved space-time can still couple to a 'spin connection'. This is why it is important to be precise when talking about such things. You've given a gut response based on your opinion but without really even defining what you're talking about.

For example, the 'spin' of a particle in particle physics is defined by how it transforms under the Lorentz group, which describes the symmetries of space-time. In general relativity the spin connection is defined by the property of the metric in normal coordinates at a given point in space-time and while it too relates to the Lorentz group the way in which it relates is different from particle spin.

Spherical geometry is a domain of mathematics which has plenty of quite nice, accessible results and which (obviously) comes with a lot of diagrams. For example it is quite a nice little learning exercise to use spherical geometry to determine why there is 5, and only 5, Platonic solids in 3D. The material is simple enough to align with intuition and experience but the mathematical formalisations required then provide ways to identify Platonic structures in higher dimensions or in curved spaces.

 

Space-time = Geometric Associations of gravity aka Mass-Attraction( Vecto?r boson? )

 

That's no excuse. Patients are a hospital's customers and the customer is always right.

 

Being a naive guy, my understandings are pretty naive too. But I can't help thinking that this is the most naive thing I have ever heard about speed in the universe, AlphaNumeric. If the high speed jets of matter and energy leaving Quasars hit whatever is in the surrounding vacuum or space (which is not itself speeding towards the quasar but is almost static and diffuse "interstellar medium kind of stuff at great distances from the Quasar) and creates a shock and Radio Waves and light and such, it's the jet material that is speeding in the universe not the intergalactic medium which is "shocked" by the speeding jet material, isn't it? Or when a cosmic ray hits an interstellar cloud and creates Cerenkov Radiation shock front, it is the speeding cosmic ray that is speeding at relativistic speeds, not the deep space intergalactic cloud far from any gravity to make it move much at any velocity in any direction, isn't it? So why this naive fantasy that speed is always "relative", when things can be seen to be the ones that are moving at high speed because they contain the high energy, not the other things which they hit? And extreme high energy cosmic rays that hit our planet's atmosphere are the ones doing the high speed in fact, not our planet or its atmosphere. Unless you claim that its just as likely that our planet's motion through the overall universe is the one that is relativistic speed and not the cosmic ray? I understand naively that SR is ok for calculating things, but it doesn't represent the whole reality of what is moving fast and what is moving slow in fact, like in my examples? That naive SR view of speed is useful but not applicable in all things, right? So using SR view "relative speed" counter arguments to Buddha like that is not really an all encompassing counter argument, is it? Shouldn't it be qualified to reflect the rest of the real motions and not just the SR view of motion as if it covers everything? If the discussion is really fully realistic, all the facts about which is the thing actually moving at relativistic speed should be what is important to find a scientific consensus, isn't it?

 

If you do an energy balance, speed is not relative. Speed is only relative if you ignore an energy balance. For example, we have two space ships one with mass M and the other with mass 2M. They are moving relative to each other with velocity V. We don't know who is moving so we might assume relative speed. However, if we do an energy balance the second ship moving would imply twice the kinetic energy, compared to the first because I doubled its mass/energy. If we assumed relative, we could have violated energy conservation by adding or destroying total system energy. To maintain the conservation of energy, there needs to be an absolute order.

When Einstein developed special relativity he included relativistic mass to require an energy balance. Speed may be relative but mass and energy are not relative to reference or else there is no basis for energy conservation. The modern trend rationalized relativistic mass away so only distance and time remained, which if true, would result in motion being relative. But if we maintain energy conservation, 2 out of 3 special relativity variables is a magic trick, that can be used to define any energy you want to make theory work out.

 

If two objects 1kg crash into each other is the energy balance important or is the energy released always equivalent to the the difference in relative speed?

v1---- v2---- v1+v2---- E1---- E2---- E1 +E2
0---- 1000 ----1000---- 0---- 500000---- 500000
100---- 900---- 1000---- 5000 ----405000---- 410000
200---- 800---- 1000 ----20000 ----320000---- 340000
300---- 700---- 1000---- 45000 245000---- 290000
400---- 600---- 1000 ----80000 ----180000---- 260000
500---- 500---- 1000 ----125000---- 125000---- 250000
600---- 400---- 1000 ----180000---- 80000---- 260000
700---- 300---- 1000 ----245000---- 45000---- 290000
800---- 200---- 1000 ----320000---- 20000---- 340000
900---- 100---- 1000---- 405000---- 5000---- 410000
1000---- 0---- 1000 ----500000---- 0---- 500000

So from that is clear that even though the relative speed is 1000 m/sec the greatest impact is when 1 object has the motion and the other is stationary.
Least energy released when the two objects share the relative motion evenly.

If mass 2 is 100 kg and mass 1 just 1 kg then mass and speed become important. Energy is calculated E = 0.5*M*V^2.


v1 ---- v2 ---- v1+v2 ---- E1 ---- E2 ---- E1 +E2
0 ---- 1000 ---- 1000 ---- 0 ---- 50000000 ---- 50000000
100 ---- 900 ---- 1000 ---- 5000 ---- 40500000 ---- 40505000
200 ---- 800 ---- 1000 ---- 20000 ---- 32000000 ---- 32020000
300 ---- 700 ---- 1000 ---- 45000 ---- 24500000 ---- 24545000
400 ---- 600 ---- 1000 ---- 80000 ---- 18000000 ---- 18080000
500 ---- 500 ---- 1000 ---- 125000 ---- 12500000 ---- 12625000
600 ---- 400 ---- 1000 ---- 180000 ---- 8000000 ---- 8180000
700 ---- 300 ---- 1000 ---- 245000 ---- 4500000 ---- 4745000
800 ---- 200 ---- 1000 ---- 320000 ---- 2000000 ---- 2320000
900 ---- 100 ---- 1000 ---- 405000 ---- 500000 ---- 905000
1000 ---- 0 ---- 1000 ---- 500000 ---- 0 ---- 500000

So it does appear that from impact tests one can determine speed. If you had two craft moving relative to each other, if they were to exchange masses they would be able to determine their actual relative velocity differences.

 

If you are doing an energy balance, relative motion violate universal energy conservation. For example, say we have a huge source that is outputting energy. We are on a space ship moving away at unknown speed. We notice a red shift but don't know how much since we don't have a good velocity. Since the red shifted energy contains less energy, than the original source emissions, our reference would short change the universal energy balance. One little rocket in motion cannot absorb energy from a huge source simply by moving; this is not relative.

If we could stop our rocket, the universe would now appear to have more energy since we lose the red shift. I am starting to think that the difference between relative energy and absolute energy, in the example above, is what we call dark energy. The true energy exists based on the source, but red shift will short change the real amount so it appear less. The difference we call dark energy.

Say we are moving in our rocket away from a giant planet. The energy leaving the planet will red shift away from mass/gravity sources, due to GR because the space-time well expands as we move away. Our motion will also cause a secondary red shift of this same energy. We get both SR and GR contributions to the energy output in our rocket reference. This double red shifts makes gravity look higher that is actually is due to the composite red shift. We add dark matter to explain the sum.

 

If something is red-shifted because the observer is moving other things will be blue-shifted, it will all balance won't it. Red-shift alone won't account for the amount of matter/energy required as dark matter.

 

Does it make difference? His local worldline started the moment he was born (became explicate in reality). We celebrate the "birthday" by "standard time", but we measure someone's life by age from birth.

IMO, time is created in the act of change from something to something in reality. Even at quantum it is physically impossible for reality to express itself all at the same time. The only TIME in the in the history of the universe where time did not exist and everything happened all at once at the same place, was during the BB. In the absence of spacetime constants, the was a single moment of a mega quantum event, at which time universal time was created along with universal reality (space, energy, matter).

IMO, there must be an equation which shows that time is a meaningless term unless something changes from one state into another and requires (needs) time, which is then created. Note: time is not causal in and of itself, it is an emergent result.

I believe the expression "in the course of time things happen" is misleading. A more correct expression would be "time is created in the course of things happening".

 

Yes, we'll have to "make" time for this study about time.
How much time will it "take"?
I wonder if I will be "allowed" sufficient time?
But all my time is already "taken up" by other things.
I'm afraid I have no time to "spare".
But I'm "having" the time of my life.

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(drunk) Hey buddy, spare me a dime....

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I'm late, I'm late for a very important date .....

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I just lost a lot of time......

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More like 7+ billion.

If you want to make statements about spin, space-time, particles etc you need to make your definitions precise, not this arm wavy stuff. For example, particle spin, such as the spin 1/2 of the electron, is not called 'spin' because the electron literally spins like a top but because when you formalise how the state of the electron is defined and interacts with electromagnetic fields you find you build a construct whose mathematical properties have a lot in common with the classical notion of a spinning top. Specifically classical angular momentum about some axis is defined by the cross product between position and momentum, \(\mathbf{L} = \mathbf{x} \times \mathbf{p}\). In terms of components and using the \(\mathbf{p} \sim \nabla\) representation you get \(L_{i} = \epsilon_{ijk}x_{j}\partial_{k}\). This satisfies a Lie bracket property \([L_{i},L_{j}] = \epsilon_{ijk}L_{k}\). All of that is just classical mechanics formalised. When you construct spin state operators in quantum mechanics, \(S_{i}\), you find they satisfy \([S_{i},S_{j}] = \epsilon_{ijk}S_{k}\). Hence why they are called 'spin' operators, they have the same mathematical property of the classical notion of spin.

The quantum notion of spin tells us how the particle state transforms when you do a Lorentz transformation. For example, a spin 0 particle doesn't do anything, it has only one spin state. A spin 1/2 particle, like the electron, has 2 possible states, spin +1/2 and spin -1/2. Under a full Lorentz rotation the particle state doesn't return to its initial configuration, you have to do 2 full rotations. A spin 1 particle, like the photon, can have spin states -1, 0 and +1. It transforms like a vector under a Lorentz transform. More generally if a particle is spin s then it can take particular spin values from the set -s, -s+1, -s+2, ... , s-2, s-1, s.

The relationship to fermions/bosons is that if the spin is integer the particle is a boson and if it is half integer it is a fermion. This is a result from quantum field theory, not a definition. It turns out that you cannot have particles with spin higher than 2 without violating a ton of consistency conditions, thus restricting attention to spin 2 particles or less. Speaking of spin 2 particles...

...the graviton is a spin 2 particle (in any models of the graviton, we have yet to observe one directly in isolation).

If quantum gravity models thus far tentatively developed are in the right ball park then space-time doesn't come with gravitons, it IS gravitons, a huge seething mass of them forming an ensemble effect we call space-time.

What you describe is not what 'spin' means in physics, quantum or classical. The graviton doesn't have a central axis, it is a point particle (or closed string if you're considering string theory). and even if it did spin isn't defined in such a way. If you think that's what spin is then you're not asking about any mainstream notion but something you've put forth, which lacks any semblance of formalisation.

I wouldn't put much stock in wellwisher's ability to discuss sound or precise mathematics or physics unfortunately.

Don't make the mistake of thinking that the use of spherical coordinates somehow implies something about the shape of the universe. What WW posted was a diagram which gives the definition of 'spherical coordinates'. Coordinates are just ways of labelling things, just like English and French are two different ways of communicating; in both cases there is no special meaning/validity for one method over another.

Space-time can be warped in all sorts of ways. Very very close to the Earth it'll have structures which are heavily influenced by the Earth's presence but this spherical warping will not be valid on a galactic scale, with the galaxy being more disk like and even that becomes insignificant when you consider cosmological scales.

What other space-time is there?

Of course, better to try than to not bother.