1
Physics, Astronomy & Cosmology / Re: Is the Higgs field, spaces conservation of energy ?
« on: 02/06/2022 13:54:35 »
Hi.
You describe vaccum energy as if it is bound to one piece of space and immovable. You need to note that what we call a piece of space or a location in space is an entirely co-ordinate dependant thing.
As far as I am concerned, the piece of space at co-ordinates x=1, y=1 and z=1 is always the same piece of space. I can point to that piece of space with my finger. It's always exactly right there, it was there when I started writing this and it will still be there tomorrow. Don't get me wrong, the air at that place can change... there can be a draft and the air can move, so I can be pointing to different bit of air tomorrow BUT that piece of space itself is still right there at co-ordinates x=1, y=1 and z=1. Things can move through that piece of space but that piece of space does not move, it is entirely identified by a set of co-ordinates x=1, y=1 and z=1.
However an astronaut can fly past me in her spacerocket and she has no way of deciding that she was moving. She could be stationary and I could moving. What she sees is that my finger is not pointing to the same piece of space all the time.
Anyway, a piece of space is an intangible and abstract thing, it is just a co-ordinate dependant description of a location. Vaccum energy can be bound to a bit of space and immovable within that piece of space but it doesn't mean anything. That whole piece of space (along with the vaccum energy that was glued into it) can be made to move just by changing the co-ordinate system I use. In the new co-ordinate system, I'm now describing something else as a piece of space which doesn't move.
One uninteresting answer is as follows: Nothing you can touch, nothing with any substance. Curvature is a mathematical description that is useful for considering the intrinsic geometry of curved surfaces. This has an easily understood and visualized interpretation for 2-Dimensional surfaces like a rubber sheet which we can embed in ordinary 3 dimensional space. The term "curvature" makes sense in that situation and our intuition agrees with the mathematical description of curvature. Riemann geometry for curved surfaces is not limited to 2 or 3 dimensions and it turns out to be very useful for modelling spacetime. So it is just a mathematical structure, an abstract object, that has this property of curvature.
Let's phrase this a different way: We could have different models for how things move through space and how something like gravity works. We can make them just as good and accurate as General Relativity - it's not even difficult, it's just tedious and a waste of time. We can take all the results from General Relativity and re-state them in a way where "curvature" or spacetime never appears. There is no need what-so-ever to believe there must be curvature in something. However, it's just easier and faster to model situation with Riemann geometry and curvature in spacetime. It will remain a useful model even if the underlying truth of the universe is very different. In all likelihood it is different, we know General Relativity has some problems like an incompatibility with Quantum theories.
I just wanted to make this clear: General Relativity and Science in general is rarely offering truth, that's all a very subjective thing for each individual. It's just a very useful model. If (and there's no reason why it should be) your ability to understand and make predictions is a significant part of believing you have a better idea of the underlying truth, then General Relativity gets you a step closer to that.
Best Wishes.
Suppose this vacuum energy that is thought to exist in every position in space is bounded with space and immovable ?I think it would be best to offer a short reply. So I'll just address one complication: Relativity.
You describe vaccum energy as if it is bound to one piece of space and immovable. You need to note that what we call a piece of space or a location in space is an entirely co-ordinate dependant thing.
As far as I am concerned, the piece of space at co-ordinates x=1, y=1 and z=1 is always the same piece of space. I can point to that piece of space with my finger. It's always exactly right there, it was there when I started writing this and it will still be there tomorrow. Don't get me wrong, the air at that place can change... there can be a draft and the air can move, so I can be pointing to different bit of air tomorrow BUT that piece of space itself is still right there at co-ordinates x=1, y=1 and z=1. Things can move through that piece of space but that piece of space does not move, it is entirely identified by a set of co-ordinates x=1, y=1 and z=1.
However an astronaut can fly past me in her spacerocket and she has no way of deciding that she was moving. She could be stationary and I could moving. What she sees is that my finger is not pointing to the same piece of space all the time.
Anyway, a piece of space is an intangible and abstract thing, it is just a co-ordinate dependant description of a location. Vaccum energy can be bound to a bit of space and immovable within that piece of space but it doesn't mean anything. That whole piece of space (along with the vaccum energy that was glued into it) can be made to move just by changing the co-ordinate system I use. In the new co-ordinate system, I'm now describing something else as a piece of space which doesn't move.
What if this background energy is growing , occupying adjacent space , rather than space expanding ?I'm not sure what you mean here. If the amount of vaccum energy was growing but space was not expanding then the density of energy should change. As I mentioned before, that might be happening but it doesn't seem to be the best or most favoured theory at the moment. It seems that vaccum energy density is remaining constant, there is a certain amount of this energy in Joules per cubic metre of space and that density is not expected to change as time progresses.
Why would a background energy move from one position to another position in space when the space , is identical space ?I can't think of any reason. You wanted to consider vaccum energy as something that could have a velocity in an earlier post. Everything has a non-zero velocity in some co-ordinate system.
Suppose that space itself does have an inherent property , a conservation of energy force , could we view this as a strong or a weak force ?Maybe. "A conservation of energy force" is not a term I'm familiar with. Is it an idea you have?
In space-time curvature what are we curving ?This is a big enough topic to have a thread of its own.
One uninteresting answer is as follows: Nothing you can touch, nothing with any substance. Curvature is a mathematical description that is useful for considering the intrinsic geometry of curved surfaces. This has an easily understood and visualized interpretation for 2-Dimensional surfaces like a rubber sheet which we can embed in ordinary 3 dimensional space. The term "curvature" makes sense in that situation and our intuition agrees with the mathematical description of curvature. Riemann geometry for curved surfaces is not limited to 2 or 3 dimensions and it turns out to be very useful for modelling spacetime. So it is just a mathematical structure, an abstract object, that has this property of curvature.
Let's phrase this a different way: We could have different models for how things move through space and how something like gravity works. We can make them just as good and accurate as General Relativity - it's not even difficult, it's just tedious and a waste of time. We can take all the results from General Relativity and re-state them in a way where "curvature" or spacetime never appears. There is no need what-so-ever to believe there must be curvature in something. However, it's just easier and faster to model situation with Riemann geometry and curvature in spacetime. It will remain a useful model even if the underlying truth of the universe is very different. In all likelihood it is different, we know General Relativity has some problems like an incompatibility with Quantum theories.
I just wanted to make this clear: General Relativity and Science in general is rarely offering truth, that's all a very subjective thing for each individual. It's just a very useful model. If (and there's no reason why it should be) your ability to understand and make predictions is a significant part of believing you have a better idea of the underlying truth, then General Relativity gets you a step closer to that.
Best Wishes.
The following users thanked this post: Armad