[AntonioLao]

when analyzing the universe as a thermodynamic system it is imperative to clarify what is the system boundary. Astronomical observations have not determined this boundary and neither is there any concrete theoretical descriptions of what or how this boundary can be explained using conventional math and physics.

it is well established that the universe is expanding. What is expanding is the spacetime structure and not the energy or material content. Although the motion of energy and matter within are limited to a max speed of approx. 186,000 miles per second, the expansion speed is much greater.

at this point, even with lack of observational data on the system boundary, questions can be posted as to whether the universe is (1) an open system, (2) a closed system, or (3) an isolated system.

an open system is one that has nonzero energy and mass exchange across the system boundary.

a closed system is defined as nonzero energy exchange, but matter content remains constant for all time.

an isolated system would have zero exchange for both energy and mass.

the majority of scientists find the descriptions for an isolated system fit the logical data of the universe.

the majority agree to the following statements about the state of the universe.

1. the dynamic control volume of the universe is increasing.
2. the entropy is increasing toward a maximum at a temperature equals zero.
3. the universe is getting colder and colder.
4. the average energy and mass density is decreasing.
5. there is not enough mass to stop or slow down the expansion.
6. the farther and deeper we look the more we discover about its past.

Final question: what is the present or future state of the universe? This cannot be answered by looking, not even by experiment, but only by guessing.

[force5]

Antonio;

Do you think it's possible to have a volume of space that is absent of both matter and energy?

[AntonioLao]

Originally Posted by force5 Do you think it's possible to have a volume of space that is absent of both matter and energy?

my answer to your question is yes and no.

Yes. the physical volume of our universe contains both matter and energy.
No. The virtual (cannot be seen) super-dimensional volume found outside the system boundary of our universe cannot contains matter and energy as we know of.

[force5]

Antonio;

Why do you think there has to be an "outside" of the universe/cosmos?

John

[AntonioLao]

Originally Posted by force5 Why do you think there has to be an "outside" of the universe/cosmos?

i cannot give any philosophical reason. But physical reasons are that densities are defined as the ratio of mass (charge) over volume (area or length). If we normalize instantaneous volume, and density to their total then there can be an inside and an outside. The outside is at a higher dimension.





from outside looking in, the universe appears as a spacetime point of lower dimension.

[force5]

I either disagree or don't understand your explanation?

Are you implying that high volume/low density space is "outside"?

Please give me another example.

[AntonioLao]

for every 3 multiples of dimension, a volume is defined.

0 1,2,3 (3D space as human understood it. This defined 1st level of volume)

0 1,2,3 4,5,6 (6D space defines a 2nd level of volume).

0 1,2,3 4,5,6 7,8,9 (9D space defines a 3rd level of volume)

0 1,2,3 4,5,6 7,8,9 10,11,12 (12D space defines a 4th level volume)

we can all experience the 3D volume but it is impossible for me to visualize higher level volumes.

densities (line, surface, volume) can be defined for each level of existence.

line density is matter/energy per unit length
surface or area density is matter/energy per unit area
volume density is matter/energy per unit volume

for higher level of existence (LOE)
higher level matter/energy must be defined first before defining density.
higher level density cannot be defined in reference to lower level matter or energy.

[force5]

Are you some how implying that our 3D universe is a subset of a greater volume of existence at a higher level? If so, what line of reasoning or math did you use to come to this conclusion?

My right brain is pretty good at visualizing almost anything once I get a handle on the concept or methodology.

Be patient with me Antonio, I'm an old man.

[AntonioLao]

Originally Posted by force5 Are you some how implying that our 3D universe is a subset of a greater volume of existence at a higher level?

Yes. And in addition, I am also implying even within our 3D universe, there may be dimensional levels of existence evident by the existence of fundamental forces. So that each LOE (level of existence) has its dominant controlling force. There should be traffics between dimensional levels. And our technologies of harnessing sources of energy did cross these boundaries of LOE. 1st, it was manual labor, 2nd: the age of tools and machines, 3rd: Industrial Revolution, the rise of steam engines, 4th, the electrical power industry, 5th, the nuclear power industry, 6th the forthcoming thermonuclear fusion. All these necessarily cross the dimensional boundary to harness energy from a lower dimension of existence.

[AntonioLao]

the common thread between these levels of energy source is the principle of the lever. As Archimedes purported to have said: "give me a place to stand and I will use the lever to move the earth."

the modern version of this principle is the conservation of angular momentum. And its quantization is the Planck's constant . But this principle can be taken down a level more when the inner product of two given torques is defined as the square of energy and its quantization is greater or equal to the square of zero-point energy of half a quantum .