Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: chimera on 30/05/2005 20:30:05
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Rene Descartes, the man who gave us our ubiquitous XYZ spatial coordinate system, and therefore no fool, strangely did not believe in empty space, or vacuums.
Now this is depicted in the scientific history books as something of a buffoonish attitude, but I think he may have a point, even supported by a bit of modern knowledge.
What he said was that there was no such thing as empty space, only matter.
Now think on what the big bang theory tells us, it was an expanding sphere of a very isotropic gas or plasma of incredible temperature. What's outside of it, is not known. Inside the volume of hot gas, which cools down, you see the gas clumping to matter, evacuating the space formerly occupied by the hot gas.
In that sense he is correct, namely that the only place matter can be, is within the space not occupied at that point by any other matter. Therefore, space is just the temporary absence of matter, but essentially still matter.
And indeed, our present finding indeed tells us raw interstellar vacuum, many orders of magnitude better than even our best artificial vacuum, is not empty - cannot be truly empty even, only temporarily.
'True nothingness' is probably that which lies outside it, but vacuum in that sense is indeed nothing but a forced disequilibrium in the distribution of matter.
Strange, eh? [:)]
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In that sense he is correct, namely that the only place matter can be, is within the space not occupied at that point by any other matter. Therefore, space is just the temporary absence of matter, but essentially still matter.
So could you say that land is just the temporary absence of water, but essentially still water? Or that where a man is standing is only the temporary absence of an African land snail, but essentially still occupied by an African land snail?
Sorry, but that is just twaddle & not even logically coherent. It doesn't logically follow that empty space is empty because it is the "temporary absence of matter". In fact it's exactly the opposite. The expansion of the universe is creating more "empty space" & if the expansion continues the less likely it is that there will be matter to fill all the empty space. The concept you put forward really isn't even deserving of an erudite reply.
Descartes was a good thinker so either he had an aberrant moment when he came up with that or you've incorrectly interpreted what he said
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Originally posted by DoctorBeaver
Descartes was a good thinker so either he had an aberrant moment when he came up with that or you've incorrectly interpreted what he said
No, I think I interpret him quite correctly, and that his theory in this case is rejected in some kind of reflex, because eithere it is too simple, too counterintuitive, or both. But again, that is to my best knowledge, exactly what he meant.
Your counterexamples are twaddle, of course. We're talking first principles here, not snails. At no point of the big bang vacuum was created, more like 'evacuated' later, by the accumulation of matter. So you go from a hogomenous gas to a very thin lumpy one.
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At no point of the big bang vacuum was created, more like 'evacuated' later, by the accumulation of matter. So you go from a hogomenous gas to a very thin lumpy one.
That is more-or-less what I was getting at. Once a certain area of space has been evacuated, because of the greater scattering of the contents the less likely it is to be refilled. The longer the expansion continues without more matter being created, the more likely it is that the evacuation will be permanent.
& yes I know my examples were twaddle. Reductio ad absurdam. [8)]
I wasn't trying to demean your intelligence, by the way. Descartes' theory may well have seemed logical given the knowledge of the universe at that time. But now we know it's expanding it just doesn't make sense anymore. Or is it me who's missing the point?
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Originally posted by DoctorBeaver
Or is it me who's missing the point?
I think so. Expansion aside, there is a difference between 'vacuum' and 'nothing'. What Descartes said, was that if you go from a gas to evacuated space, since all the matter and energy has lumped into stars and planets and more dense clouds of gas, the remainder is still not really 'empty'.
Now if this dilute gas aka vacuum is expanding, that could well be because however thin, it is still of higher pressure than what's outside of this universe, namely real nothingness, of no pressure, meaning the universe might even have 'surface tension'. Note that these expanses of thin gas would expand much faster than the solidified matter, if at all.
Come to think of it, that's not far off from what's observed.
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Now that makes more sense. I think it was the phrase "temporary evacuation" that was throwing me off track.
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Now the main mental switch is accepting the fact, that what we see as vacuum, is only an absence of matter. It once was occupied by it, and can be again. At no point in time of this universe 'space' was essentially different from 'matter'. The opposition or dichotomy is a false one. Even talking about 'space-time' does not really make the coin drop, in that sense.
Space is just matter on vacation, to paraphrase my sig...
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Now you've done it again. "...that what we see as vacuum, is only an absence of matter. It once was occupied by it, and can be again."
Yes, it can be, but the more "dilute" space becomes, the less likely it is that any given area will be re-occupied.
I fully appreciate the difference between vacuum & nothingness, but I don't see that as the issue except insofar as a vacuum will always be at a greater pressure than nothingness
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I thought twice about jumping in on this good debate, but I can't resist. You two remind me of 17th century philosophers, except you haven't brought up angels and pinheads yet...
The debate about space and matter stretches way back, and our present philosophy can be blamed on Isaac Newton. It was he who declared space "absolute". He pissed off a lot of people in the Royal Society at that time, who thought that space could not be absolute, but only relative between material objects. They were right, of course, but nobody but Newton was in a position to describe it all in quantitative terms. So he did, and space became absolute, relative to the "fixed stars". The stars aren't fixed, and even Einstein didn't know that, but at least he had the imagination to throw off the shackles of Newtonian fixed-space, and describe it in relative terms.
Both of you should read Einstein's book, "Relativity". It goes through this in a lot of detail, with "mathematics at the level of a university matriculation exam" (A. E.). He describes most of your debate points, and it is a very good read.
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Originally posted by DoctorBeaver
Now you've done it again. "...that what we see as vacuum, is only an absence of matter. It once was occupied by it, and can be again."
Yes, it can be, but the more "dilute" space becomes, the less likely it is that any given area will be re-occupied.
I fully appreciate the difference between vacuum & nothingness, but I don't see that as the issue except insofar as a vacuum will always be at a greater pressure than nothingness
[sorry gsmollin, we're on a roll here, and I'll check out the book]
True, you cannot say there WILL be matter, but more importantly, it is the only place for matter (and energy, and light) to go TO, if you see what I mean. This very thin soup is still a far cry of true nothingness, perhaps even light cannot cross 'true nothingness' for lack of substrate, bringing back the whole discussion in fact about 'aether' with the vacuum taking that epithet nolens volens, if you will.
And remember, our lab vacuums are not even a billionth as empty as deep space. We cannot do it, let alone 'tear a rip' in the fabric of' 'reality' or spacetime. That would require enough force to not only overcome gravity, but also you'd have to push two entire 'halves' of the universe apart over a tiny space, but they might as well be like the most gigantic Magdenburger half-globes, and I don't think even 50 kazillion horses could pull it off.
But again, I think it might be possible light does not travel in true nothingness, and likewise matter can only go where it once was, in that sense, to 'vacuum' space.
[and frankly, I never heard Einstein about what's *outside* our turf]
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Originally posted by gsmollin
I thought twice about jumping in on this good debate, but I can't resist. You two remind me of 17th century philosophers, except you haven't brought up angels and pinheads yet...
Just on a side-note: we *are* discussing a 17th century philosopher, and angels and pinheads were dediced at the Synod of Nicae in the 4th century, if I remember correctly, and I think they agreed on the number 133.
Angels that is, that could dance on the head of a pin, great controversy in early Christianity, needles(s) to say.
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But again, I think it might be possible light does not travel in true nothingness, and likewise matter can only go where it once was, in that sense, to 'vacuum' space.
Light cannot travel through nothingess because the very fact that a photon is there means that it cannot be empty. It therefore must become a vacuum as soon as the photon enters it.
I met a some Angels at a rock concert once & I sure-as-Hell wouldn't want to try putting any of them on a pinhead!
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Once again, philosophers, I must kibbitz. Quantum mechanics requires a Newtonian space, with absolute timelines and coordinates. Relativity requires a 4-dimensional continuum, no absolutes. Mixing these two has led numerous mathmaticians and physicists to dance on the head of a pin. I don't know if any angels got off, but you can just get wrapped around an axle with this, like verybody else has, so far.
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gsmolin - there's nothing unwarranted or intrusive about your comments (yes, I know what kibbitz means! [:p])
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Relativity requires a 4-dimensional continuum, no absolutes
Does Riemann geometry not have co-ordinates? I can understand that there would be difficulties with it but I would have thought not impossible
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Originally posted by gsmollin
Relativity requires a 4-dimensional continuum, no absolutes.
Isn't the speed of light an absolute?
And is a 4-dimensional space not just 3-dimensional space doing a rerun, slightly different this time? I mean, it's the same 3 dimensions, just later. Time is just a sequence counter, in that sense. Not a real dimension always present, like the other 3. Those other three are ALWAYS present. You cannot have something 2D within this universe, it will always have SOME thickness, and therefore a 3d dimension. But 'time' you can leave out of quite a few models. Only when you wish to show a *process* time comes into the picture.
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And is a 4-dimensional space not just 3-dimensional space doing a rerun, slightly different this time? I mean, it's the same 3 dimensions, just later. Time is just a sequence counter, in that sense. Not a real dimension always present, like the other 3. Those other three are ALWAYS present
Imagine a 2D object being moved along a 3rd dimension by an external force. The 2D object could not percieve that force as such as it exists in a dimension unaccessible to the object. The object wouldn't realise it was actually moving but things around it would change as a result of that movement.
Now, in my analogy, substitute a human being for the 2D object and have Time as a 4th D through which we are being moved by an external force. We can easily percieve & understand the 3rd D which was so mysterious to the 2D object and it's Time (the 4th D) which presents us with conceptual problems. It's quite possible that the 4th D is always present, just that we can't percieve it.
Think also of a photon. It travels at the speed of light which, I believe, as a result of time dilation means that from its perspective the entire life of the universe passes in zero time. For it, the 4th D doesn't exist. (Something in the murky depths of my brain tells me that the photon situation has some profound importance but the concept won't quite manifest itself yet.I'll probably wake up at 3am & shout "Eureka!")
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I'm thinking out loud here so please forgive if it ends up being total rubbish.
Gravity distorts spacetime & in intense gravitational fields time goes completely mental. Rather than time merely being affected by gravity, could it be a function of gravity or maybe a consequence of gravitational effects?
In my previous reply I referred to a hypothetical force propelling us through time. Gravity affects the 3 dimensions we are aware of & the 4th which we postulate, so what if gravity exists in a dimension other than 1 of those 4 yet exerts an influence on them?
It's not only gravity that makes time go silly, relativistic speeds do the same. Returning to my 2D object, there could be a variety of factors that could cause it to move through a 3rd D - e.g. a breeze, someone pushing with their finger, etc.. Einstein said that gravity & acceleration are the same thing - who am I to argue with him!. But what if they're not? What if they are merely 2 identical effects of different phenomena? The 2D object might say that breeze and a pushing-finger are the same thing as the effect of both is identical: but we can understand that they're totally different.
erm... I'm not sure where I'm going with this. I'll have to think about it a bit more. But I'll leave this post here so people have the chance to point & laugh at me. [V]
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See, how picking up where 17th century geniuses left off aint so bad. It really makes you *think*.
Currently reading Leibniz's Monadologies. Weird, but very interesting.
(found that tip in one of Lee Smolin's books, who in turn got that advice from Julian Barbour, who's some physicist's guru of sorts - 'read Leibniz')
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Are you saying that I'm an anachronism?
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Originally posted by chimera
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Originally posted by gsmollin
Relativity requires a 4-dimensional continuum, no absolutes.
Isn't the speed of light an absolute?
And is a 4-dimensional space not just 3-dimensional space doing a rerun, slightly different this time? I mean, it's the same 3 dimensions, just later. Time is just a sequence counter, in that sense. Not a real dimension always present, like the other 3. Those other three are ALWAYS present. You cannot have something 2D within this universe, it will always have SOME thickness, and therefore a 3d dimension. But 'time' you can leave out of quite a few models. Only when you wish to show a *process* time comes into the picture.
The speed of light is an absolute. The 4 dimensions are not. Time is not a sequence counter. That is the Newtonian viewpoint. You can't leave time out, except in mathematical models. Physically its always 4-D. Different viewpoints of the same events all have their own clocks running at different speeds, and will report a different process. You can always take a "snapshot", but the snapshot had to occur at a "time". A snapshot at a different time shows a different picture.
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Originally posted by DoctorBeaver
Are you saying that I'm an anachronism?
Would make me antiquated. And I'm younger than you....[:I]
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Buddha is younger than me!
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Originally posted by DoctorBeaver
Think also of a photon. It travels at the speed of light which, I believe, as a result of time dilation means that from its perspective the entire life of the universe passes in zero time. For it, the 4th D doesn't exist. (Something in the murky depths of my brain tells me that the photon situation has some profound importance but the concept won't quite manifest itself yet.I'll probably wake up at 3am & shout "Eureka!")
Just read a description in a book of how 'God would see time', himself being 'beyond time'. Eerily similar, same words almost... Didn't He even say at one point: 'I am the Light'? Did those 'ancients of old' sense this connection somehow? Even though I'm not a Christian or anything, I find this coincidence rather striking...
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Rob - I mentioned in another post how the teachings of traditional Judaic Qaballa are freakily similar to modern theories in physics. There is also a belief in most occult systems that the entire universe is based on vibrations - higher beings & spirits vibrate at a much faster rate: that being the reason we don't usually see them. String theory ring a bell here?
Occult tradition also states that there are many more dimensions than the ones we can percieve. Sound familiar?
The more I learn about physics & cosmology, the more astounded I am at how similar to occult thinking it is. But that could raise a whole subject for discussion.
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There are lots of occult and religious teachings, some of which bear a resemblence to modern science, and some that are simply contradicted by modern science. There are also many scientific teachings, some of which bear a resemblence to modern science, and some that are simply contradicted by modern science.
The difference between the two is the scientific method. Philosophers, religious or not, and scientists think the same kinds of thoughts; they may even be the same people. The scientists goes on to verify his philosophy, er, postulate, by experimental means. He may be right or wrong, but he tries to discover the truth by experiment. The philosopher decides himself that he correct, and the religious man consults his god.
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GS - that's very well put. But let me ask you this. Did you try to verify every single fact that you were taught or did you take it for granted that your teachers were right? For instance, have you ever sought verifiable corroboration that the battle of Hastings was in 1066?
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gsmollin, I think your rendition of the art of science is a bit simplistic in the sense that science in your view only deals in things that can be experimented upon, and the rest is nice, but baloney. I don't think life accepts such artificial borders between science and philosophy, or likewise with science and religion.
Furthermore you really don't have to convince us of the scientific method, at least not at every opportunity whenever we're having an armchair debate on ur-soup or the deaper moanings of life, and stuff. Without trying to sound snide, it's a bit like being told you're loafing or something working at McDonalds while your should be flipping burgers. Sorry, science to me is more than reading instruments and measurements or discussing 'hard' numbers. Armchair philosphy CAN lead to new insights, I think. It is nothing to be sneezed at.
And at least half the fun, I think. Again, I hope you don't take this as offensive. You know I value your opinions greatly.
OK, Eth: think of this - light is the 'fixator' or 'effectuator' of time. The particles travelling at lightspeed experience time as if it was standing still, yet propagate all information about cause and effect in this universe. This is not contradicting Einstein btw, he says that only when two events follow so quickly on each other that light cannot travel between them in that time, that those two events *could* be seen by an observer (given the right speed and angle) to have happened in reverse order.
Meaning no information could travel between them that would lead to a conundrum.
So in a sense, lightspeed is a kind of 'sanity check' of the universe to keep things tidy in the cause-and-effect department. And time is somehow the light moving 'sideways' as you described, in a sense. So, photons standing still in time while 'updating' the rest of the universe of what happened locally. Make some strange sense.
Now people can say this is just a coincidence, light's no propagator of time, it's only there so we can see stuff, very handy, but immaterial. I say: why would you need a deeper 'mechanism' than this that you are already looking at? I invoke Occam's razor. [:)]
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OK, Eth: think of this - light is the 'fixator' or 'effectuator' of time
Is it? Isn't it time that defines how fast light can travel? No matter the frame of reference you're observing from, light can only travel a certain distance in a certain time. Is it true to say that only a given amount of time can pass between a photon moving from point A to point B?
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Originally posted by DoctorBeaver
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OK, Eth: think of this - light is the 'fixator' or 'effectuator' of time
Is it? Isn't it time that defines how fast light can travel?
Just as my measure tape dictates the distance it will travel? [:)]
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It's a monkey-puzzle indeed. My intellect isn't large enough to fathom it
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Actually, as I said before, time is the only thing we CANNOT directly measure, the rest we can. This would suggest to me to take time more (or less, depending) seriously as a candidate for 'side effect' of the month, not the others. In that sense measurement, and the ability to, is ofcourse always nice. There gsmollin and I agree.
I'll repeat my summons to the scientific community: What's the measure, particle, or the observed *mechanism* of Time?
A deep and resounding silence is what normally follows at this point....
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Noone? thought so.
Light - the unmoved mover. Mmm. Nice title for a little piece on inductio ad absurdum where the rules do not rule certain conclusions out, so they *could* be true, however repulsive the idea.
How often do we not do exactly follow that recipe in quantum mechanics, and did not soomeone once observe that whatever remains, however improbable, must be true?
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chimera, maybe you are looking for this forum: http://www.thenakedscientists.com/forum/forum.asp?FORUM_ID=6
At the top of the page in this forum, it says "science", so if I remind you about the scientific method, then no offense intended, but I am on topic, and you are not.
In the future, I'll not comment on your religious posts. I shall try to stay polite, but in many forums you would be getting scatagorical spam rants.
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Originally posted by gsmollin
chimera, maybe you are looking for this forum: http://www.thenakedscientists.com/forum/forum.asp?FORUM_ID=6
At the top of the page in this forum, it says "science", so if I remind you about the scientific method, then no offense intended, but I am on topic, and you are not.
In the future, I'll not comment on your religious posts. I shall try to stay polite, but in many forums you would be getting scatagorical spam rants.
gsmollin:
- philosophy is part of science
- I asked for a scientific answer to the phenomenon of time, I get none
- I made a remark about a coincidence between religion and science, and a correct one I think - refute it if you will, simple complaining about it does not help anyone
- I make no religious posts, since I am not a religious person.
- if I recall correctly your first intrusion into this discussion was with a historically incorrect joke, but correct me if I'm wrong. In certain forums you'd be flamed for several technical reasons right there and then, if I'm not mistaken.
Fortunately we aren't, eh?
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Actually, as I said before, time is the only thing we CANNOT directly measure, the rest we can. This would suggest to me to take time more (or less, depending) seriously as a candidate for 'side effect' of the month, not the others.
I said in another thread that it had occurred to me that maybe time was a side-effect ( I think I said function, but it's the same thing)
GS & Chimera - don't start getting bitchy! [:o)] There are some good points being espoused by both sides. And I think if anyone is guilty of bringing religion into some of these debates it's probably me
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philosophy is part of science
Of course it is. In areas that are at present impirically unprovable, theory is no different to philosophy. If a philosophical viewpoint is logically consistent then in what way is it inferior to purely conjectural mathematics?
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Frankly, gsmollin brought in religion himself with his first posting, kind of bring-your-own-straw man.
But when you ask a direct question he's pas a la maison. If he cannot quote the manual, the problem does not exist, sorry. Or rather not sorry, but you get the 'you must be methaphysically challenged' routine, and labeled 'probably contageous', and therefore hasta la vista.
Shame.
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Originally posted by DoctorBeaver
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And is a 4-dimensional space not just 3-dimensional space doing a rerun, slightly different this time? I mean, it's the same 3 dimensions, just later. Time is just a sequence counter, in that sense. Not a real dimension always present, like the other 3. Those other three are ALWAYS present
Imagine a 2D object being moved along a 3rd dimension by an external force. The 2D object could not percieve that force as such as it exists in a dimension unaccessible to the object. The object wouldn't realise it was actually moving but things around it would change as a result of that movement.
Now, in my analogy, substitute a human being for the 2D object and have Time as a 4th D through which we are being moved by an external force. We can easily percieve & understand the 3rd D which was so mysterious to the 2D object and it's Time (the 4th D) which presents us with conceptual problems. It's quite possible that the 4th D is always present, just that we can't percieve it.
Think also of a photon. It travels at the speed of light which, I believe, as a result of time dilation means that from its perspective the entire life of the universe passes in zero time. For it, the 4th D doesn't exist. (Something in the murky depths of my brain tells me that the photon situation has some profound importance but the concept won't quite manifest itself yet.I'll probably wake up at 3am & shout "Eureka!")
I've been thinking a lot about this specific post the last couple of days.
How's this. We have problems imagining a 4D environment. 3D is our max. Time is perceived as motion. Light and radation travelling at lightspeed do not perceive time.
Now turn this topsy-turvy in your mind, like pulling something inside-out, and you can just barely imagine (I can) the universe MOVING in the 4th dimension via lightspeed, which we see with our human brains as 3D + motion and time. So any radiation (like light) travelling at lightspeed is actually the universe moving along this unseen 4th line, and any particle actually doing that, not perceiving normal 3D time at ALL. They are mutually exclusive.
[added for clarification:] This means that light is standing still in the 4th dimension, and ONLY moves in 3. Anything moving slower than light will still be moving in the 4th dimension and notice time. Only if you get to lightspeed time comes to a complete standstill.
This means time is an inverse function of motion in the 4th dimension. Anything stopping movement in the 4th dimension altogether automatically goes to lightspeed in the other 3.
Inversely this means that the slower you go in 3D, the faster your movement in the 4th is. And explains why you cannot go faster than light - without going back in time, if movement along that path is even allowed (!). Would rule out faster than light drives - you can not go slower than a full standstill in the 4th dimension - at lightspeed in the others.
Also throws some light (pun intended) on the fact why an 'observer' is so important in Quantum Mechanics, even if it's not a conscious being but an apparatus doing the observing, they always LOOK (via light or other radiation). That is not the passive thing it's made out to be, in this scenario. It's an act.
Time is a great teacher, but unfortunately it kills all its pupils - Hector Louis Berlioz
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I just realised this scenario is essentially Minkowski's model of 4D space, which took Einstein a full 4 years to accept, btw. Gosh, Eth, we're geniuses, just 80 years too late... or have only 80 years to catch up, whatever you prefer.
So a bit of philosophising can lead to pure science after all, which just goes to show.
What Minkowski does not talk about, though is the fact that this means that EVERY object moving at a different speed has its own time, with accompanying number of slices, at ANY speed, even our slow terrestrial ones. This could be an alternative solution to the turtle and the hare problem - the increments in time-events are not of equal length for both objects.
Also, if two objects in close proximity in 3D achieve the same speed in this 4th dimension there could also be an 'unseen' attraction *because* of this similarity in 4D speed. This could be interptreted as gravity in 3D, and would work stronger for solid matter than for energy, but also for energy.
I think this would mean that if you send two high-energy lightbeams they would eventually converge, because of this. They'd be going at the same speed in 4D, so they fall towards each other, without any visible mechanism in the normal 3 dimensions to be found.
Time is a great teacher, but unfortunately it kills all its pupils - Hector Louis Berlioz
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[xx(]
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Originally posted by DoctorBeaver
[xx(]
Yeah, I guess so.
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Originally posted by chimera
...I asked for a scientific answer to the phenomenon of time, I get none ...
http://plato.stanford.edu/entries/spacetime-bebecome/
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Originally posted by gsmollin
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Originally posted by chimera
...I asked for a scientific answer to the phenomenon of time, I get none ...
http://plato.stanford.edu/entries/spacetime-bebecome/
Thank you.