What is the fabric of space made of


by planck
Tags: fabric, space
brainstorm
brainstorm is offline
#145
Jul14-10, 09:50 PM
P: 1,117
Quote Quote by apeiron View Post
All we have left is the self-interaction of the vacuum. But it continues to have a pressure, it continues to expand, it continues to have the same essential dissipative structure.
Dissipative in what sense? That decreasing pressure draws particles/energy from higher pressure surroundings?

I am suggesting it goes into its surroundings, into creating its surroundings.
By "surroundings," I meant energetic matter and EM waves. What did you mean?

When the big bang cooled sufficiently, anti-matter and matter could condense out. But almost all of it immediately annihilated to create the spreading/cooling CMB. A tiny fraction of matter remained. Which will eventually get swept up into blackholes and radiated away too.
So most of the energy of the initial big bang went into expansionary motion then? Would you agree that spatial separation between matter is a form of potential energy? Or do you think potential energy simply dissipates as objects move into ever weaker orbits in a gravitational field?
apeiron
apeiron is offline
#146
Jul15-10, 12:21 AM
PF Gold
apeiron's Avatar
P: 2,432
Quote Quote by brainstorm View Post
So most of the energy of the initial big bang went into expansionary motion then? Would you agree that spatial separation between matter is a form of potential energy? Or do you think potential energy simply dissipates as objects move into ever weaker orbits in a gravitational field?
Of course matter is a temporary added complication to the basic picture. I am talking about the basic picture - which is just a bath of radiation spanning event horizons in comoving volumes. Or rather, that is what Davies and Lineweaver are talking about.

So there would be no localised gravitational potentials as the CMB is so evenly spread.
brainstorm
brainstorm is offline
#147
Jul15-10, 09:45 AM
P: 1,117
Quote Quote by apeiron View Post
Of course matter is a temporary added complication to the basic picture. I am talking about the basic picture - which is just a bath of radiation spanning event horizons in comoving volumes. Or rather, that is what Davies and Lineweaver are talking about.

So there would be no localised gravitational potentials as the CMB is so evenly spread.
I'm confused. As far as I know there is no existence of "space" except as separation between points of matter despite their gravitational attraction for each other. Even massless energy is supposed to trace the contours of spacetime as defined by gravitational field topography. What defines the event horizons and comoving volumes except energized matter? If massless energy itself can stake off gravitational topography, how does that occur? How can photons exert gravitation without mass?
Dmitry67
Dmitry67 is offline
#148
Jul15-10, 10:04 AM
Dmitry67's Avatar
P: 2,456
Quote Quote by brainstorm View Post
If massless energy itself can stake off gravitational topography, how does that occur? How can photons exert gravitation without mass?
Again, Mass is not a source of gravity
Stress energy tensor is.
robheus
robheus is offline
#149
Jul23-10, 10:05 AM
P: 143
What are thoughts "made of"?

Space is merely a concept to differentiate different locations of objects in three dimensions.

In the theory of relativity space should be thought of a space-time and space-time itself does not have independend existence from matter/energy.

So, you could say that space-time is the mode of existence of matter/energy.

Space-time is not "made" of something else, yet space-time is never completely empty of matter/energy.

So, physical space is not just abstract mathetamatical geometry, where there is space-time there is matter/energy and vice versa.
brainstorm
brainstorm is offline
#150
Jul23-10, 10:37 AM
P: 1,117
Quote Quote by robheus View Post
So, physical space is not just abstract mathetamatical geometry, where there is space-time there is matter/energy and vice versa.
Good post. I think you could look at space as the vacuum inside a closed, de-pressurized container. The walls of the container are impelled to collapse into each other except the tensile strength prevents them from doing so. However, since there is no container-wall around the Earth, sun, galaxies, etc., the force pulling objects and particles apart has to be dynamic energy, from the big bang or just their motion relative to each other or however you describe it. Gravity is interesting, though, in that it relaxes as things move farther away from each other, so the "vacuum" elasticity relaxes as distances increase. So as gravity approaches zero, it seems like space could simply transcend gravitational relations, but how could gravitational attraction between two objects ever reach absolute zero? If it can't, then how could space-time ever exist in the absence of matter-energy?
planck
planck is offline
#151
Jul23-10, 02:04 PM
P: 45
First of all, I'm glad that this thread is still alive and kickin!


Quote Quote by robheus View Post
What are thoughts "made of"?
You can quantify a thought. I would think that a synapse is fired and from there (or maybe a little before that) you could trace the path of that physical process within the brain. I think the argument could be made that the energy involved in a thought is tangible.

Space has to be tangible too.


Quote Quote by robheus View Post
Space-time is not "made" of something else, yet space-time is never completely empty of matter/energy.
Then why is it curved. That's the real question that I have. If space and time are intertwined, then there has to be something that links it. A "velcro" perhaps.

I'm tellin ya, space is something.
GeorgCantor
GeorgCantor is offline
#152
Jul23-10, 02:43 PM
P: 419
Quote Quote by planck View Post
First of all, I'm glad that this thread is still alive and kickin!



You can quantify a thought. I would think that a synapse is fired and from there (or maybe a little before that) you could trace the path of that physical process within the brain. I think the argument could be made that the energy involved in a thought is tangible.


Energy is not a thought and a thought is not energy.

Either thoughts aren't real or energy isn't real. You could believe that thoughts are emergent but nothing could stop you from believing, for instance, that God is emergent from the configuartion of galaxies in the observable part of the universe.
nismaratwork
nismaratwork is offline
#153
Jul23-10, 03:00 PM
P: 2,281
Thoughts are the result of the transmission of energy in the form of electrical impulses and neruotransmitters. It is not a matter of one synapse, but many. If you think that a thought cannot be quantified, you'll have to explain that to EEG rigs that allow people to type on a screen. Our technology isn't at the "mind reading" stage, but that doesn't mean that such would be impossible. That is a completely different issue from what constitutes spacetime.

GeorgCantor: Your either or is misleading, I assume for the purposes of introducing religion... again.
robheus
robheus is offline
#154
Jul23-10, 03:00 PM
P: 143
Quote Quote by planck View Post

Space has to be tangible too.



Then why is it curved. That's the real question that I have. If space and time are intertwined, then there has to be something that links it. A "velcro" perhaps.

I'm tellin ya, space is something.
It's matter/energy that connects space and time.
nismaratwork
nismaratwork is offline
#155
Jul23-10, 03:06 PM
P: 2,281
Quote Quote by robheus View Post
It's matter/energy that connects space and time.
That seems unlikely; energy exists within spacetime, not as some connective tissue between two 3 and +1 dimensions.
GeorgCantor
GeorgCantor is offline
#156
Jul23-10, 03:38 PM
P: 419
Quote Quote by nismaratwork View Post
GeorgCantor: Your either or is misleading, I assume for the purposes of introducing religion... again.

I believe it's not. And it has nothing to do with religion.


Thoughts are the result of the transmission of energy in the form of electrical impulses and neruotransmitters. It is not a matter of one synapse, but many. If you think that a thought cannot be quantified, you'll have to explain that to EEG rigs that allow people to type on a screen.

Who/what is typing on the screen?

You are making it sound like it's something so simple when in fact it's the most mind-bending occurence in nature.

Either we don't have freewill and consequently thoughts are illusion, or we have freewill but matter is an illusion. One could assume emergent phenomena but it will not be satisfying to everyone.
planck
planck is offline
#157
Jul23-10, 03:41 PM
P: 45
Here's some food for thought. Imagine it's T=0. At this time, existence is non-existent. But the theory is that a great explosion occurred that introduced existence. If we want to take the cosmological route, we can speculate that the hole where existence was introduced came from somewhere (parallel universe planes touching each other ?). Now, take into account that there is a theory that our gravity is leaking constantly. Where's it going? But more importantly, where's it coming from? Are there holes and fissures in our spacetime where things are coming and going? Could space itself be "leaking?" It's already stretching.
alt
alt is offline
#158
Jul24-10, 02:09 AM
PF Gold
P: 322
Quote Quote by planck View Post
Here's some food for thought. Imagine it's T=0. At this time, existence is non-existent. But the theory is that a great explosion occurred that introduced existence. If we want to take the cosmological route, we can speculate that the hole where existence was introduced came from somewhere (parallel universe planes touching each other ?).
But if there was somewhere from where existence was introduced, wasn't THAT somewhere, itself existence ?
alt
alt is offline
#159
Jul24-10, 02:16 AM
PF Gold
P: 322
Quote Quote by GeorgCantor View Post
Who/what is typing on the screen?
Interesting question. Who formed that thought ? And who thought to form THAT thought ? Sounds like an infinite regress .. or emergent phenomena (whatever that means).
robheus
robheus is offline
#160
Jul24-10, 06:49 AM
P: 143
Quote Quote by planck View Post
Here's some food for thought. Imagine it's T=0. At this time, existence is non-existent. But the theory is that a great explosion occurred that introduced existence. If we want to take the cosmological route, we can speculate that the hole where existence was introduced came from somewhere (parallel universe planes touching each other ?). Now, take into account that there is a theory that our gravity is leaking constantly. Where's it going? But more importantly, where's it coming from? Are there holes and fissures in our spacetime where things are coming and going? Could space itself be "leaking?" It's already stretching.
You are running into deep problems with this kind of propositions. A time at which time began can by definition not exist since when you referring to "begin" you already assume time to exist, so this means time can not be said to have begun at all.
robheus
robheus is offline
#161
Jul24-10, 06:51 AM
P: 143
Quote Quote by alt View Post
But if there was somewhere from where existence was introduced, wasn't THAT somewhere, itself existence ?
right.

It's a meaningless thought to think that "existence" somehow "began".

Even though you can gramatically express such grandiloque internally contradicting statements, they have no semantical meaning.
Noja888
Noja888 is offline
#162
Aug4-10, 02:46 PM
P: 53
My Brother and I have a saying I think he said it first - not sure if we stole it from somewhere...

"Space is Time demonstrated - Time is Space demonstrated" - I would propose time as we observe it did not begin until space began. Both seem interconnected and I am guessing the true mechanism of space and time are on a higher tier level of existence. If you can travel light speed, time stops for you relative to everything else. Is that 'catching up with time' as space-time information 'moves' at the speed of light you are now moving at the same speed? Time will affect you less because you caught up to its motion. Its motion is not linear like the 3 spatial dimension motion we are familiar with but motion in the time direction. Loosely speaking here of course - I am not a PHD!


Register to reply

Related Discussions
Space Time Fabric Special & General Relativity 8
Is space fabric or fluid? Special & General Relativity 8
Space-time fabric General Astronomy 1
the fabric of space time Special & General Relativity 1
Space/time fabric General Physics 2