What Is The Material Structure of Spacetime?

a reply to: tkwasny

Time is space that is in the state of kinetic.
Space is time that is in the state of static.
Both are composed of the base material that is the wake of the infinite velocity and angular diversity of the Singularity.

Interesting post. I'm having a little trouble with the premise of a "wake" in Vacuum.

Most important is why the one Singularity even exists at all. You wouldn't believe it if I told you.

Okay… I won't then.

a reply to: Astyanax

Had a ton of replies today, saved yours for last because I knew it would be best. Sorry for the delay.

The light emanates from a point in space that is already moving away from us faster than light, and the expansion is accelerating.

If light radiates in every direction it would come back and eventually reach us, right? I didn't know matter could move at the speed of light either. I'm old school, though.

What is the fastest reorder speed of matter moving relative to us? Its a galaxy or cluster of them, right?

Well considering that we have never actually detected gravity waves and considering that general relativity does not jive with quantum mechanics, it isn't absolutely certain that space-time is actually a malleable fabric as defined by Einstein. The vacuum is the medium in which all energy exists, assigning properties to it may be equivalent to assigning properties to nothing, which is why people like Nikola Tesla couldn't accept the idea of curved space-time. That isn't to say I think Einstein is wrong, but Nikola has yet to be definitely proven wrong also.

I hold that space cannot be curved, for the simple reason that it can have no properties. It might as well be said that God has properties. He has not, but only attributes and these are of our own making. Of properties we can only speak when dealing with matter filling the space. To say that in the presence of large bodies space becomes curved is equivalent to stating that something can act upon nothing. I, for one, refuse to subscribe to such a view.

~ Nikola Tesla

originally posted by: ATSAlex

originally posted by: NorEaster

I think that it's a vector system that's useful for object location.

I don't believe in a material Aether.

Ok, making an analogy here, kind of like a ruler is used to measure the distance between 2 objects, Right? But still the ruler is made out of something, be it wood, plastic, metal, etc. What do you think space time is made of?

I was thinking in my first post that it was made up of Dark matter / Dark energy. Which is something of an unknown and unproven I suppose, but have to name it in some way.

To you, what is the space time fabric made out of? You already stated what is it used for in a way that makes sense at least to me.

Thanks!

Spacetime is an intellectual abstraction. A human construct. I have no idea what open space is made of, but I do know the difference between a vector mapping strategy and something that actually exists as primordial and in spite of the thoughts of human minds. I'm asking a question here. I'm not sandbagging an answer. I honestly don't know what comprises the vacuum of open space.

Spacetime is only the acknowledgement that if you place an object within open space at a proximity position point (relative to - say - the Earth) at one moment in time, it can result in a very different outcome than if you place that same object at that same proximity point (again, relative to the Earth) at a different moment in time. In fact, one moment in time could bring that object into a collision with another object (the Moon, perhaps), whereas a different moment in time could put that object into a stable orbit around the Moon. For applied physics, Einstein's Spacetime theory was very valuable, but for the search for ultimate truth concerning what exists as real within our universe, it doesn't seem to make any sense whatsoever.

a reply to: netbound

Excellent post and thread reference. Thanks!

a reply to: intrptr

If light radiates in every direction it would come back and eventually reach us, right?

Because 'spacetime is curved'? Actually, we don't know whether the universe is flat, open or closed. Even our best measuring devices (mostly satellites that look at very ancient light) can't tell which it is.

I didn't know matter could move at the speed of light either. I'm old school, though.

Matter isn't moving at or faster than the speed of light. Space itself is expanding faster than light (at least, this is the case at cosmic distances from an observer). This does not violate relativity precisely because space has no material structure. The matter contained in the expanding space moves along with the volume of space it occupies, so relative to that space it is moving slower than light. It's only FTL to a very distant observer (who, in fact, can't see it).

What is the fastest reorder speed of matter moving relative to us? Its a galaxy or cluster of them, right?

I believe some quasars are the fastest objects in the universe, moving at relativistic velocities from our viewpoint. But they are still moving slower than light... well, most of them, anyway. Superluminal motion

originally posted by: Astyanax
Matter isn't moving at or faster than the speed of light. Space itself is expanding faster than light (at least, this is the case at cosmic distances from an observer). This does not violate relativity precisely because space has no material structure.

Question: If space itself does not have a material structure or fabric or aether (whatever), then how can it expand at all?

I'm trying to imagine something immaterial (i.e not physical in nature) that still has the ability to expand into (within) something much larger than itself. From my experience, only material things can expand. So there must be a boundary (or outer membrane) to the universe that separates itself from whatever is beyond that edge that would allow us to say it's expanding, no? If so, shouldn't this delineation imply a material composition to the universe?

The matter contained in the expanding space moves along with the volume of space it occupies, so relative to that space it is moving slower than light. It's only FTL to a very distant observer (who, in fact, can't see it).

Again another question: (only from a mind trying to understand within the current construct of reality here on earth)

What is causing the movement of matter within space? Is it just gravity? If the expansion of the universe is said to be pulling everything away from everything else, seemingly defying gravitational interplay, then how does this occur? I realize dark energy is somewhat taboo to bring up here, so how do we account for an immaterial spacetime structure that doesn't in some way play role in the movement of celestial bodies? Is it simply so, because the universe is perceived to be expanding at FTL, so it must not have a material (of matter) structure?

Something seems to be missing here....

I realize these are very basic questions.

I think this would be like asking a totally colorblind person to describe the color red. We might have to exist outside of the confines of space-time to understand what it's really made of.

a reply to: PhotonEffect

I'm trying to imagine something immaterial (i.e not physical in nature) that still has the ability to expand into (within) something much larger than itself.

the metric tensor in general relativity relates precisely how two events in spacetime are separated. A metric expansion occurs when the metric tensor changes with time (and, specifically, whenever the spatial part of the metric gets larger as time goes forward). This kind of expansion is different from all kinds of expansions and explosions commonly seen in nature in no small part because times and distances are not the same in all reference frames, but are instead subject to change. A useful approach the subject is to visualize space itself growing between objects, without any acceleration of the objects themselves, rather than as objects in a fixed "space" moving apart into "emptiness". The space between objects grows or shrinks as the various geodesics converge or diverge. Wikipedia

METRIC TENSOR
In general relativity, the metric tensor (or simply, the metric) is the fundamental object of study. It may loosely be thought of as a generalization of the gravitational field familiar from Newtonian gravitation. The metric captures all the geometric and causal structure of spacetime, being used to define notions such as distance, volume, curvature, angle, future and past. Wikipedia

So there must be a boundary (or outer membrane) to the universe that separates itself from whatever is beyond that edge that would allow us to say it's expanding, no? If so, shouldn't this delineation imply a material composition to the universe?

There is no boundary. Space is not expanding into anything.

What is causing the movement of matter within space?

The three (or four) fundamental forces in htier various guises. However, the expansion of space is not caused by these forces but by an ill-defined causative principle to which we give the name dark energy.

Two things to note.

1. The rate of expansion depends on the distance between the observer and the region observed.
   
   
2. In regions of space where there is a large enough concentration of matter, the expansion is halted. Stars in a galaxy aren't moving apart due to the expansion of space.

how do we account for an immaterial spacetime structure that doesn't in some way play role in the movement of celestial bodies?

It does play such a role. This is what general relativity explains.

A fascinating alternative to the expansion of space, recently put forward, is that the universe has been gaining weight — or rather, mass.

a reply to: Astyanax

the metric tensor

Thanks for the links. I will have to work my mind up to this one.

There is no boundary. Space is not expanding into anything.

So you are assuming an open or flat system? What happens when we introduce the multi-verse?

A fascinating alternative to the expansion of space, recently put forward, is that the universe has been gaining weight — or rather, mass.

More interesting reading.

I personally believe gravity creates spacetime and not the other way around. get far enough away from gravity and you dont have spacetime. Gravity is spacetime and is created by the other known forces that bring particles together.

Reply to PhotonEffect

So you are assuming an open or flat system? What happens when we introduce the multi-verse?

Whather the universe is open, closed or flat, there is still nothing outside it. What is the Universe Expanding into?

Oddly enough, the existence of multiple universes has no consequences for this discussion.

*

Reply to Xeven
The trouble with that theory is that gravity follows an inverse square law, so you can never get far enough away from a massive object to escape it. Besides, if there's no space, how do you get far enough away?

originally posted by: Astyanax
Reply to PhotonEffect

So you are assuming an open or flat system? What happens when we introduce the multi-verse?

Whather the universe is open, closed or flat, there is still nothing outside it. What is the Universe Expanding into?

Oddly enough, the existence of multiple universes has no consequences for this discussion.

The explanation in that article is a bit of a cop out. Just because one could not leave a finite curved universe doesn't mean you can't think about the void which surrounds it and ask questions about it. The only reason you can't leave such a universe is because space-time curves around back into its self, creating a type of 4D spherical universe. But that sphere can be described as existing in and expanding into some type of void.

The most popular, albeit outdated, notion of a multi-verse is such a void filled with many such 4D spherical universes. We now know there is probably no strange void surrounding the universe because we know with a high level of probability that space-time is flat and infinite. This means our old notion of the multi-verse is completely wrong and it also forces us to completely rethink the nature of the big bang.

a reply to: ChaoticOrder

ust because one could not leave a finite curved universe doesn't mean you can't think about the void which surrounds it and ask questions about it.

There is no 'void that surrounds it'.

originally posted by: Astyanax
Reply to PhotonEffect

So you are assuming an open or flat system? What happens when we introduce the multi-verse?

Whather the universe is open, closed or flat, there is still nothing outside it. What is the Universe Expanding into?

Yes I came across this link in my own research. The raisin bread analogy seems to ignore that theres material between the raisins, and that there's an outer edge. Inside/Outside. For my mind, Ill need a better analogy.

Oddly enough, the existence of multiple universes has no consequences for this discussion.
That there's nothing outside of our universe?

I'm sorry guys, but I have to disagree with the comments and the acceptance that spacetime is a real phenomenon. 'Space' is a word that describes an aspect of nature, the concept of which is entirely predicated on the content in space that hold spatial vector relationships with each other. Space itself has no properties except in a mathematical equation where imagination can invent all sorts of exotics, but it does not mean they have an independent existence beyond that of the imagination that invented them. You cannot 'curve' space, because you cannot interact with nothing, and 'nothing' is exactly what space is.

It is the same with time. Time is nothing more than the measurement of our perception of duration. That is all it is. Time is like space, it is nothing. When you put nothing with nothing you still have nothing, and because nothing has no properties of any kind, you cannot interact with it. There is no force of any kind that can interact and affect nothing.

Planets and stars, like our earth and sun, do not actually curve space itself, but mathematically, it can be treated as if they do so. Whatever the earth and sun affect around them, it is not space. Comets and and other travelling bodies, including quanta from the outpouring from stars and novae, may indeed describe arcs and curves in their trajectories, but that is not due to actual space itself being curved, it is due to the interaction of magnetic fields of massive bodies. It is the reason why the moon does not crash into the earth, which you would expect it to do if the earth curved the space around it. The moon is in fact moving away from our planet, and in the ancient past, billions of years ago, the moon was very much closer to the earth than it is now.

Spacetime really is nothing more than a useful mathematical construct which has led to some rather strange thinking and conclusions.

With regard to matter. Any matter that has mass, cannot move at the same speed as a photon, which as you are all aware is the quantised unit of electromagnetic radiation. Photons are massless, but have a high interactive property. Neutrinos, on the other hand, have mass, but hold very low interactive properties, which is why they can travel through dense matter and not interact with anything...this being a case where neutrinos can travel faster than light can through matter.

If the neutrino did not have any mass at all, and because it has very low interactive properties, we should not have detected one yet, if ever we could. The fact that we have detected neutrinos means that it must have mass, or that it had slowed down to a speed where it was able to interact with matter in its environment? The former is self-explanatory, whereas the latter begs the question...what force is there that can slow down a low interacting neutrino?

One other thing to consider is, no light source can travel away in the opposite direction of light travel faster than the light it creates.

Astyanax:

Whether the universe is open, closed or flat, there is still nothing outside it.

True, and it is called space. Here is how to define that void. It is 'space' without content. The universe is problematically described. Do we say that a universe is only that region of 'space' that has content in it...i.e., matter; galaxies, stars, quanta, etc. Or do we mean, the universe is absolute space into which the content of matter is expanding into? By the latter, I infer that the universe is not expanding, but that newly-created matter is pushing already created matter ever deeper into space...that is the expansion.

Of course, this raises profound questions, especially about the forces creating new matter. Suppose they never was just one singular 'Big Bang', but that Big Bangs are occurring all the time in other regions of the universe, but so far away that we can only detect their occurrence by the ubiquitous presence of a cosmic background radiation?

originally posted by: elysiumfire
With regard to matter.
If the neutrino did not have any mass at all, and because it has very low interactive properties, we should not have detected one yet, if ever we could. The fact that we have detected neutrinos means that it must have mass, or that it had slowed down to a speed where it was able to interact with matter in its environment? The former is self-explanatory, whereas the latter begs the question...what force is there that can slow down a low interacting neutrino?

The mass is not the reason for the interaction in the case of the neutrino. The interaction in and of itself is coupled to the weak nuclear force, which acts upon the neutrino regardless of its mass. Neutrinos having mass is actually a drop out/consequence of their flavour oscillation behaviour, they are required to have mass by the standard model if they are to oscillate in the way we observe. It has nothing to do with them interacting at all. Infact, the first neutrino interactions where observed without any requirement in theory for them to have mass, and in many respects, them being massless was always an assumption or placeholder.

so the information in the above quote is incorrect and somewhat misleading.

ErosA433:

...the information in the above quote is incorrect and somewhat misleading.

It is and it isn't. I speculated on two aspects: a) due to detection, neutrino must have mass - which they do; and b) that the neutrino slowed down to a speed where weak interaction can take place?

Without interaction there is no detection. Neutrinos do not interact electromagnetically, and are unaffected by magnetic fields. As you have correctly stated, it is the weak nuclear force that oversees neutrino interaction, but the weak nuclear force only acts across extremely small distances, so for neutrino interaction to take place, it has to encounter a force that acts on it other than the weak nuclear, and that other force is gravity acting on the mass of the particle, which clearly shows that gravity is indeed a force of its own. It is in this context my meaning was meant. Apologies to all.