The universe consists of at least three independent realities and their infinities: (1) the spatial reality; (2) the temporal reality; (3) the physical reality.
1. The spatial reality is the infinite emptiness which is space; space would be empty—a pure vacuum—except for the presence of the matter/energy which is the physical reality; the spatial reality is infinite in duration; the spatial reality is dimensionless, unbounded, limitless.
In the concept of the spatial reality we find the first infinity, of dimension, because of the limitless dimensions of space. If we were to create a latticework of rigid rods, specified to be of invariable and unbending finite length, absolutely straight and of absolute length, set at ninety degrees to each other, and absolutely parallel to each other, with no rods touching other rods except for intersections, and labeled for orientations from a starting point North<->South, East<->West, and Up<->Down, we would find that there would be no final or finite number of rigid rods we could add to the latticework, the number of rods which could be added to the latticework would be infinite, limitless, hence we would visually and tactually experience the infinity of space which is the spatial reality.
Thus, there is the spatial reality which is the spatial infinity.
2. The temporal reality is the concept of time which is the measurement of the occurrences of events in sequences by means of time-intervals; time as measured by invariant time-intervals is the same for all observers—time measured by means of invariant time-intervals in clocks which are motion/gravity-sensing and self-adjusting or otherwise synchronized by radio signals always show an increase in clock face readings; time moves forwards into the future, is irreversible and therefore is asymmetrical; there was never a beginning to time, nor will there ever be an ending of time.
In the concept of the temporal reality we find the second infinity, of time, with no final measurement of clock face readings when clocks created with invariable time-intervals --
(A) are set to measure timepoints into the future, from Timepoint T0 (Timepoint Zero):
(B) are set to measure time into the past:
(C) are set to measure both time into the past and into the future in a continuum:
The ‘now,’ which is the ‘present,’ is the current configuration of matter/energy, the present configuration of matter/energy, which is the physical reality, in the spatial reality; the now results from the immediate past configurations and the inertial masses of things, objects, comprised of matter/energy both at rest and in motion, and the future results from the combination of the immediate past and present configurations of matter/energy and the inertial masses of things at rest and in motion. Thus, at T0 we have a specific current and present configuration of matter/energy which resulted from the configuration of matter/energy in the immediate past at T-1 and which will cause the future configuration of matter/energy at T+1.
Photographs and videos taken with conventional cameras show in two dimensions the local configurations of matter/energy which are the now and the present when the photographs or videos were taken. Photographs and videos are thus frozen records of previous configurations of matter/energy. Because of their nature, the frozen records of previous spatial/temporal/physical configurations which are revealed by conventional cameras and videos are two-dimensional. If we could create cameras which could take photographs or videos in three dimensions, then we would see and experience the precise position of each thing comprised of matter/energy and therefore the precise configuration of all matter/energy at each Timepoint, at each of a series of Timepoints, therefore we would see the previous/past configurations which cause the present configuration and future configurations. We would see the flow of time as the flow of now/present configurations of matter/energy.
Thus, there is a temporal reality which is a temporal infinity.
3. The physical reality is the matter/energy (including gravity and the electric charge) which comprises all things [objects] and events [relationships between/among things]; the physical reality fills part if not all of space; its duration is infinite—matter/energy can be changed in form but never destroyed—matter/energy is indestructible: E = mc2 and m = E/c2; its quantity is finite—the sum total of matter/energy is a constant [Thermodynamics]; the physical reality as matter/energy is the source of causality, wherein things/events comprised of matter/energy as causes cause/create things/events as effects; nothing comes from nothing, therefore something can only come from something else.
In the concept of the physical reality we find the third infinity, the duration of matter/energy by the measurement of time into the past and into the future, with no beginning of time and no ending of time (with no final face readings or temporal measurements of clocks using invariable time-intervals), and we also find the first finity, the total quantity of matter/energy, the sum total of matter/energy, being a finite quantity.
Thus, there is a physical reality comprised of matter and energy which is the infinity of physical duration and which is the finity of the quantity of matter/energy.
We therefore find three realities—the spatial reality, which is space, the temporal reality, which is the measurement of time, and the physical reality, which is the matter/energy which is the source of causality, and we find three infinities—the infinity of unbounded space, the infinity of the endless measurement of time (using invariable time-intervals), and the infinity of the duration of matter/energy, and we find the finity of the quantity of matter/energy.
Because there was no beginning to time, nor is there an ending, because there was no beginning to space, nor is there an ending, because there was no beginning to matter/energy, nor is there an ending, because nothing comes from nothing/something can only come from something, and because matter/energy is the source of all causality, then if a Big Bang occurred the energy was present as matter/energy, matter/energy was present as the source of the causality of the Bang, space was also present as the unbounded place within which the Bang could occur, and time was also present as a concept only needing to be realized which would provide the measurement of the occurrence of the Bang. The space, time and physics—matter/energy—needed for the Big Bang was present prior to the Bang. And if a Big Crunch occurs, space, time and physics—matter/energy—will be present after the Crunch.
We, as individual human beings, exist as configurations of matter/energy of the physical reality within the spatial and temporal realities.
If gods exist, they, too, exist as configurations of matter/energy of the physical reality within the spatial and temporal realities. They may be comprised of matter/energy not presently observed and therefore not presently known by human beings, but, nevertheless, they are comprised of matter/energy of some kind. They may have more knowledge and capabilities (powers) than than human beings, but, nevertheless, they are comprised of the matter/energy which is the physical reality. They may have existed without beginnings, and may continue to exist without endings, because they are changeless, because there is no inertia which can cause them to change, or because they can avoid the inertia which can cause them to change, but they are, again, nevertheless, comprised of the matter/energy which is the physical reality. Therefore, if they exist, the gods are physical, not spiritual.
When we combine the spatial and temporal realities and infinities with the reality, infinity and finity of the physical reality we have a concept of the universe as the space, or spatial reality, in which exist the things and events comprised of the matter and energy of the physical reality the configurations of which can be measured by invariable time-intervals of the temporal reality. And we see that there can only be one universe in which exist all things/events comprised of matter/energy. As there is only one physical reality, only one spatial reality and only one temporal reality there can be only one universe.
We live in the now, the present temporal reality, and we experience the current configuration of the physical reality within the spatial reality.
We experience the infinities of space, time and physics, and the finity of physics in the quantity of matter/energy. The infinities of space, time and physics and the finity of physics are all objective, because they can be observed and measured and therefore experienced independently of ourselves and our limitations and prejudices, by other creatures, and by machines.
With the three realities and infinities of space, time and physics, and with the finity of physics, we now have a concept of the universe which is based upon reality itself, is readily observable and therefore is verifiable.
The universe is defined as the combination of the three realities: the spatial reality, the temporal reality, and the physical reality.
We call the spatial reality space, we can call the temporal reality time, and we can call the physical reality physics.
Thus, the universe is defined as the combination of space, time and physics.
We commonly think of 'universe' as 'all space/time/physics.' Thus, the term 'universe' generally means 'all there is.'
Some theorists speak of 'multiple universes' and 'parallel universes' as if there could be more than one universe. Thus, if people choose to speak of 'multiple universes' and 'parallel universes,' then the term 'universe' does not mean 'all there is,' and we will need to create another term, such as 'superuniverse' to mean 'all there is.'
But 'universe' means all there is,' therefore all 'multiple universes' and 'parallel universes' would have to exist within the 'universe,' which strongly suggests that if each 'multiple universe' and/or each 'parallel universe' consisted of/was comprised of three realities, space, time and physics, there would have to exist within one 'universe' more than one set of three realities, and this simply does not make sense; therefore, there is only one 'universe,' one 'all there is,' one set of three realities, one set of space, time and physics, and thus there cannot be 'multiple universes' and 'parallel universes.' And so it is that there is no 'superuniverse' but, instead, there is only one 'universe.'
Any set of mathematics which appears to prove that there exist more than one universe, as in 'multiple universes,' or 'parallel universes,' does not fit reality, and violates Einstein's dictum that "the mathematics must fit the physics," meaning mathematics must always be subservient to physics, to the physical reality, and never superior to physics.
Thus, 'universe' continues to mean 'all there is.'