Post by: wucko on 02/04/2012 20:02:54
"nohing is" and "everything is not" against "everything is" and "nothing is not". the second statement is a paradox, the firs isnt.
to me, this would imply, that the original question isnt correct, that its opposite IS the question: "can nothing not exist"
Post by: CliffordK on 03/04/2012 06:17:02
And, in what we consider space, or the area beyond Earth's atmosphere is a good approximation.
There is controversy on whether there is some kind of a fundamental "fabric of space" which provides a medium for the propagation of light, and planetary movement, and etc, as well as the universal speed limit of light.
Thus, if one had a container from which all matter was removed with a perfect vacuum, the "fabric of space" would still remain.
Post by: yor_on on 03/04/2012 06:46:19
Will the geometry exist?
Post by: Æthelwulf on 04/04/2012 13:12:50
Take away the mass.
Will the geometry exist?
Yes, it will. The reason why is because the equations of relativity dictate that:
What this equation says is that if you remove all the mass in the universe, the curvature could still be non-zero. This is because of the presence, but highly ellusive today gravitational waves. So geometry can exist without matter.
It is for this reason, I believe that matter emerged from curvature. In effect, if you add enough curvature into a specific region, matter should appear.
Post by: Nizzle on 04/04/2012 13:45:50
In effect, if you add enough curvature into a specific region, matter should appear.
This is going towards the Photon-only theory...
Post by: Æthelwulf on 04/04/2012 15:25:03
In effect, if you add enough curvature into a specific region, matter should appear.
This is going towards the Photon-only theory...
Maybe.
Post by: JP on 04/04/2012 16:35:38
Take away the mass.
Will the geometry exist?
Yes, it will. The reason why is because the equations of relativity dictate that:
What this equation says is that if you remove all the mass in the universe, the curvature could still be non-zero. This is because of the presence, but highly ellusive today gravitational waves. So geometry can exist without matter.
It is for this reason, I believe that matter emerged from curvature. In effect, if you add enough curvature into a specific region, matter should appear.
Remember this is space-time, so if you really have no matter and energy for all space and all time, it turns out that the only thing that determines the shape of the universe is the cosmological constant. If you set that to zero, you get a flat universe everywhere. It still has geometry ("flat" is a geometry), but it has no curvature. Essentially, the entire universe has the geometry of special relativity. This is obviously a bit silly to take seriously, since what would a matterless/energyless universe mean?
Now, if you still take no traditional matter/energy, but add in a cosmological constant, then space can be curved, though you still have limited potential geometries.
If you're simply looking at a region of space that contains no matter/energy, then it can also be curved, since matter/energy elsewhere in the universe can be causing space-time to curve or it could be emitting gravitational waves.
I don't think anyone knows for sure whether having "enough curvature" could cause matter to appear spontaneously from the vacuum. It's intriguing, but probably needs quantum gravity, and we don't have a satisfactory theory for that yet.
Post by: Æthelwulf on 04/04/2012 17:27:26
Take away the mass.
Will the geometry exist?
Yes, it will. The reason why is because the equations of relativity dictate that:
What this equation says is that if you remove all the mass in the universe, the curvature could still be non-zero. This is because of the presence, but highly ellusive today gravitational waves. So geometry can exist without matter.
It is for this reason, I believe that matter emerged from curvature. In effect, if you add enough curvature into a specific region, matter should appear.
Remember this is space-time, so if you really have no matter and energy for all space and all time, it turns out that the only thing that determines the shape of the universe is the cosmological constant.
If we cannot speak about energy defining the shape of the universe, then saying we can only infer on the cosmological constant seems like a paradox to me, since the CC is in fact the energy density of the overall universe.
Could you clarify this for me?
I can see you are well educated in physics.
Post by: Æthelwulf on 04/04/2012 17:29:01
Take away the mass.
Will the geometry exist?
Yes, it will. The reason why is because the equations of relativity dictate that:
What this equation says is that if you remove all the mass in the universe, the curvature could still be non-zero. This is because of the presence, but highly ellusive today gravitational waves. So geometry can exist without matter.
It is for this reason, I believe that matter emerged from curvature. In effect, if you add enough curvature into a specific region, matter should appear.
Remember this is space-time, so if you really have no matter and energy for all space and all time, it turns out that the only thing that determines the shape of the universe is the cosmological constant. If you set that to zero, you get a flat universe everywhere. It still has geometry ("flat" is a geometry), but it has no curvature. Essentially, the entire universe has the geometry of special relativity. This is obviously a bit silly to take seriously, since what would a matterless/energyless universe mean?
Now, if you still take no traditional matter/energy, but add in a cosmological constant, then space can be curved, though you still have limited potential geometries.
If you're simply looking at a region of space that contains no matter/energy, then it can also be curved, since matter/energy elsewhere in the universe can be causing space-time to curve or it could be emitting gravitational waves.
I don't think anyone knows for sure whether having "enough curvature" could cause matter to appear spontaneously from the vacuum. It's intriguing, but probably needs quantum gravity, and we don't have a satisfactory theory for that yet.
''It still has geometry ("flat" is a geometry), but it has no curvature.''
got a problem with this as well. His equation actually predicts curvature without matter... confused slightly.
Post by: JP on 04/04/2012 18:13:11
If the stress-energy tensor is zero and the cosmological constant is zero, then the Ricci curvature tensor is necessarily zero. The curvature tensor describes the deviation from flat space-time, and when it's zero, your space-time geometry is flat.
Post by: Æthelwulf on 04/04/2012 18:18:16
Ok, here's what I recall from my GR coursework with a bit of help from Googling the curvature tensor:Hmmm....
If the stress-energy tensor is zero and the cosmological constant is zero, then the Ricci curvature tensor is necessarily zero. The curvature tensor describes the deviation from flat space-time, and when it's zero, your space-time geometry is flat.
... well as far as I know, gravitational waves are not trivial, nor are they really the presence of matter, so you may have a curved space without the presence of gravity.
Maybe as a little project, you can investigate this with another scientist and see who is valid. :)
Post by: Æthelwulf on 04/04/2012 18:21:37
Ok, here's what I recall from my GR coursework with a bit of help from Googling the curvature tensor:Hmmm....
If the stress-energy tensor is zero and the cosmological constant is zero, then the Ricci curvature tensor is necessarily zero. The curvature tensor describes the deviation from flat space-time, and when it's zero, your space-time geometry is flat.
... well as far as I know, gravitational waves are not trivial, nor are they really the presence of matter, so you may have a curved space without the presence of matter.
Maybe as a little project, you can investigate this with another scientist and see who is valid. :)
Sorry, at first there I said not the presence of matter... that was not true I realized, a bad slip. I mean't matter.
Post by: JP on 04/04/2012 18:40:08
Ok, here's what I recall from my GR coursework with a bit of help from Googling the curvature tensor:Hmmm....
If the stress-energy tensor is zero and the cosmological constant is zero, then the Ricci curvature tensor is necessarily zero. The curvature tensor describes the deviation from flat space-time, and when it's zero, your space-time geometry is flat.
... well as far as I know, gravitational waves are not trivial, nor are they really the presence of matter, so you may have a curved space without the presence of gravity.
Maybe as a little project, you can investigate this with another scientist and see who is valid. :)
Well if they exist without mass/energy, then as far as I can tell, Einstein's field equations are wrong. Of course, I believe you can have something generate the gravitational waves, and they can propagate into an empty region of space-time, but if you have a truly energyless/matterless universe, I don't see how this could happen...
But then, such a universe might not be physically meaningful anyway.
Actually, this is very reminiscent of EM waves. We know that EM waves certainly can propagate in a vacuum, devoid of any matter. But we also know that EM waves require sources to be generated, so in a truly matterless universe, you shouldn't have EM waves.
Post by: Æthelwulf on 04/04/2012 19:02:22
Ok, here's what I recall from my GR coursework with a bit of help from Googling the curvature tensor:Hmmm....
If the stress-energy tensor is zero and the cosmological constant is zero, then the Ricci curvature tensor is necessarily zero. The curvature tensor describes the deviation from flat space-time, and when it's zero, your space-time geometry is flat.
... well as far as I know, gravitational waves are not trivial, nor are they really the presence of matter, so you may have a curved space without the presence of gravity.
Maybe as a little project, you can investigate this with another scientist and see who is valid. :)
Well if they exist without mass/energy, then as far as I can tell, Einstein's field equations are wrong. Of course, I believe you can have something generate the gravitational waves, and they can propagate into an empty region of space-time, but if you have a truly energyless/matterless universe, I don't see how this could happen...
But then, such a universe might not be physically meaningful anyway.
Actually, this is very reminiscent of EM waves. We know that EM waves certainly can propagate in a vacuum, devoid of any matter. But we also know that EM waves require sources to be generated, so in a truly matterless universe, you shouldn't have EM waves.
Hios equations are not exactly wrong. There seems to be a dicotemy no one can agree on. His theory has proved right hundreds of times, literally.
Now we need to find a logical path.
Post by: Bill S on 04/04/2012 21:29:52
As an absolute amateur, it does seem to me that the nothings that scientists discuss tend to be very “somethingy” nothings.
Could it be that absolute nothing is just too dull to catch anyone’s interest?
Post by: Æthelwulf on 05/04/2012 14:01:59
There seems to be an endless potential for the discussion of nothing.
As an absolute amateur, it does seem to me that the nothings that scientists discuss tend to be very “somethingy” nothings.
Could it be that absolute nothing is just too dull to catch anyone’s interest?
Maybe it goes deeper than that. For instance, four years ago to my knowledge, many people used to say space was nothing. It turned out that space really isn't nothing, but is filled with energy in a virtual form.
Perhaps then, the reason that nothingness can exist is because we cannot infer on it - what we have no knowledge about is where the imagination fills.
Post by: yor_on on 06/04/2012 22:45:36
Geometry is gravity, gravity is coupled to mass and energy. But a 'space' without matter, aka mass, is indeterministically defined as I see it. I would expect this thought up 'space' to behave very much as if it was 'flickering', 'here', as we get emanations creating a SpaceTime, just to disappear again. That is if seen with eyes of a God. What one might argue is that for anything 'existing' in such a 'space' the question becomes if it can exist at all, that is , can the arrow create the illusion of a continuum?
The 'flat' space you're envision here would not be 3D.
=
changed non to in-deterministically as that is what I mean :)
And yes Wulf, I was wondering where you got those gravitational waves from too :) they would need mass or a he* of a lot of energetic emanations (creating rest mass with an arrow) to be noticeable, as a guess.
Post by: Airthumbs on 08/04/2012 18:30:14
It also seems to be dependent on your definition of nothing, as quoted above nothing is the empty vacum of space. However this is not nothing, in fact it is full of things!!
In my opinion the true sense of nothing is exactly that, it is quite hard to comprehend really, a bit like infinity. I have to say in my opinion both of these statements only exist in a mathematical context. Pi is an example but I do like the fact that this is called an irrational number.
In our physical universe I would argue that infinity and nothing are both a figment of our imagination due to a lack of understanding which almost seems to be in line with religious origins; A substitution of something that cannot exist logically to explain an observation.
Post by: wucko on 11/04/2012 17:52:55
There seems to be an endless potential for the discussion of nothing.
As an absolute amateur, it does seem to me that the nothings that scientists discuss tend to be very “somethingy” nothings.
Could it be that absolute nothing is just too dull to catch anyone’s interest?
Maybe it goes deeper than that. For instance, four years ago to my knowledge, many people used to say space was nothing. It turned out that space really isn't nothing, but is filled with energy in a virtual form.
Perhaps then, the reason that nothingness can exist is because we cannot infer on it - what we have no knowledge about is where the imagination fills.
the very point of this thread is: you can not gather ANY information when you ask yourself "can nothing exist", but you could inform yourself on something if you ask the opposite "can nothing not exist".