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The Fabric Of Spacetime. It Has To Be Something But What?
In my mind I can conceive a space that is totally empty such that however large or small it is all the possible measurements are zero. Yet if I pass a photon through it it's original electromagnetic waveform will propagate through it long after the original particle that emitted it has been left behind. I could put my imagined space of nothing close to a galaxy and see the same beam of light bending in it's course from passing through my imagined box of 'nothing'.
But that is just the tip of the iceberg of the stuff that 'nothing' does. Clearly it has to be something.
This may sound trivial but if Admiral Nelson is one day to be followed by Captain Kirk of the Starship Enterprise we really need to start to look at nothing. Nothing seems to be more important than anything.
But that is just the tip of the iceberg of the stuff that 'nothing' does. Clearly it has to be something.
This may sound trivial but if Admiral Nelson is one day to be followed by Captain Kirk of the Starship Enterprise we really need to start to look at nothing. Nothing seems to be more important than anything.
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It's entirely possible that in a few hundred years or so the answer below will be known to be wrong but at the moment it's better to think of "the fabric of spacetime" as a matter of convenience, rather than actually being some kind of stuff.
The main reason for this is because if spacetime actually has its own substance then we are unlikely ever to be in a position to notice ourselves. The main place we might see that it is stuff is inside a black Hole, but unfortunately they have an annoying tendency to kill you before you could tell anyone. The scale, at any rate, has to be ludicrously small -- we're talking distance or time intervals measured in trillionths of trillionths of trillionths of a metre, and a similarly tiny fraction of a second. To probe that kind of scale requires basically too much energy (or, more importantly, money), at least for the foreseeable future, for it to be realistic to expect that we could test.
Still, we can hope that maybe we'll understand it one day. In the meantime, the best theory of spacetime we have, ie General Relativity, is a bit dishonest. Space and time aren't really "things" so much as "convenient points of reference to describe where you are in the Universe".
The main reason for this is because if spacetime actually has its own substance then we are unlikely ever to be in a position to notice ourselves. The main place we might see that it is stuff is inside a black Hole, but unfortunately they have an annoying tendency to kill you before you could tell anyone. The scale, at any rate, has to be ludicrously small -- we're talking distance or time intervals measured in trillionths of trillionths of trillionths of a metre, and a similarly tiny fraction of a second. To probe that kind of scale requires basically too much energy (or, more importantly, money), at least for the foreseeable future, for it to be realistic to expect that we could test.
Still, we can hope that maybe we'll understand it one day. In the meantime, the best theory of spacetime we have, ie General Relativity, is a bit dishonest. Space and time aren't really "things" so much as "convenient points of reference to describe where you are in the Universe".
Thanks for some good answers, probably better than the question deserved!
I'm semi-retired now and probably spend an unhealthy amount of time on my own. When I'm out walking my dog in the pretty countryside around my village my mind tends to ponder on such questions.
The best analogy for spacetime/the quantum vacuum/ quantum foam/ cosmic strings... is the computer one. If the laws of physics, chemistry et cetera are the operating system and processes like life are programs aka apps these days, then spacetime is the format of the hard drive and universes are partitions.
I suspect it's a lot more sophisticated than FAT32 or NTFC though!
I'm semi-retired now and probably spend an unhealthy amount of time on my own. When I'm out walking my dog in the pretty countryside around my village my mind tends to ponder on such questions.
The best analogy for spacetime/the quantum vacuum/ quantum foam/ cosmic strings... is the computer one. If the laws of physics, chemistry et cetera are the operating system and processes like life are programs aka apps these days, then spacetime is the format of the hard drive and universes are partitions.
I suspect it's a lot more sophisticated than FAT32 or NTFC though!
It's an interesting analogy and indeed it's not totally impossible that it's the reality as well! Again, it's unlikely to be totally testable -- is a computer capable of determining its own nature without being able to look outside itself? -- but people can certainly explore it. The problem again is one of scale. The difference between "spacetime is really a continuum of nothingness" and "spacetime has some finite substructure to it" is likely too small to ever detect.
Hmm...
A lot of what I said in my first post is probably still true -- but the gravitational theorists are certainly having fun trying to make sense of it all!
http://
A lot of what I said in my first post is probably still true -- but the gravitational theorists are certainly having fun trying to make sense of it all!
http://
Computers do not walk with dogs and contemplate metaphysics :0)
They can give answers to humanly constructed questions, but can't ask questions themselves, (unless programmed to do so by a human brain.)
There is no such thing as spacial 'nothing' (by definition) so it seems an unworthy subject of study.
There is also no such thing as 'nothing' in relation to time.
As the Zen master said;
“Sitting quietly, doing nothing, Spring comes, and the grass grows, by itself.”
― Matsuo Bashō
They can give answers to humanly constructed questions, but can't ask questions themselves, (unless programmed to do so by a human brain.)
There is no such thing as spacial 'nothing' (by definition) so it seems an unworthy subject of study.
There is also no such thing as 'nothing' in relation to time.
As the Zen master said;
“Sitting quietly, doing nothing, Spring comes, and the grass grows, by itself.”
― Matsuo Bashō
Which,of course, indicates that the human brain may also not be coming up with anything new either; just spewing out the latest result of some background processing of its inputs, that the conscious part fools itself into thinking it is responsible for, using its "free will". May just be a complicated calculating machine after all. Still what it doesn't know isn't supposed to hurt it.
//just spewing out the latest result of some background processing of its inputs,//
That may well sum up the modern scientific brain OG; I ponder if today's scientists haven't lost their sense of wonderment in their unseemly scramble to publish papers in a vainglorious attempt to be first.
Robert Hooke, in his superbly illustrated 'Micrographia' published in 1665 studying the house-fly through the newly discovered microscope wrote;
'It seems that God has bejewelled the fly in compensation for its lack of size, he has crowns and blooms on his head against which anything possessed of the richest of men must pale... so much beauty concentrated in so small a space.'
That may well sum up the modern scientific brain OG; I ponder if today's scientists haven't lost their sense of wonderment in their unseemly scramble to publish papers in a vainglorious attempt to be first.
Robert Hooke, in his superbly illustrated 'Micrographia' published in 1665 studying the house-fly through the newly discovered microscope wrote;
'It seems that God has bejewelled the fly in compensation for its lack of size, he has crowns and blooms on his head against which anything possessed of the richest of men must pale... so much beauty concentrated in so small a space.'
The main problem (notwithstanding my calling NTFS, NTFC) with the mainly Sci Fi cosmic computer theory mentioned by the late Ian M Banks and others I'm sure, as well as those who invoke a mathematical foundation for reality, is that it just leads to the question of who designed and built the cosmic computer and who built them... or who created the mathematics. The latter to me is like saying that the universe, life, and evolution existed to produce, in the form of the human hand, the best fit for a glove!
Yes, language exists first and grammar is our way of defining it, but some would say one needs grammar before you should speak. The snail does well producing a beautiful spiral shell without knowing anything about the mathematics of it.
In fact having written that I can see several flaws there myself however I'll leave it to stand
In fact having written that I can see several flaws there myself however I'll leave it to stand
That the snail doesn't know about the maths behind shell production doesn't mean it isn't important. What the snail does "know" is that it wants a shell that is fairly study, economical in space and relatively efficient to produce. The spiral shape produced largely meets these conditions, and there is a fairly profound mathematical reason for this. It would do well to read about, among other things, the Principle of Stationary Action (a brief summary being something along the lines of "the universe is a lazy so-and-so") and Noether's first Theorem (a very informal statement being that "symmetry is a very good way to be lazy").
From such relatively basic principles it's possible to understand a great deal about the structure of nature. I'm even tempted to say that the Stationary Action principle is almost enough on its own to provide a reason for the Universe being the way it is -- because any other way would just be "more difficult" -- although in that I've stepped outside mathematics and into philosophy so it's certainly a statement open for debate.
From such relatively basic principles it's possible to understand a great deal about the structure of nature. I'm even tempted to say that the Stationary Action principle is almost enough on its own to provide a reason for the Universe being the way it is -- because any other way would just be "more difficult" -- although in that I've stepped outside mathematics and into philosophy so it's certainly a statement open for debate.
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