1. Introduction
This paper examines the model of a timeless primordial state (PS) of pure space preceding everything, the emergence of time from it, and the subsequent evolution of space-time. It results from a series of earlier investigations v[
1,
2,
3,
4,
5] each of which has provided ingredients for a new overall concept. Because it’s often about subtleties, and in order to achieve a largely self-contained presentation, some of our earlier calculations, that are important for this paper, are reproduced here (mostly in the Appendix) in compact form and adapted to the present needs. This is important also for the reason that from them partly other and partly new conclusions are drawn. Unlike the earlier studies, which dealt with the origin of
, space expansion, DE, and a multiverse, this paper focuses on the origin and structure of space and time. Essential concepts on which it is based are conveyed below.
1. Already since early antiquity there has been felt a need for putting an end to the endless chain of cause and effect that makes each cause the effect of a preceding cause. For this, Aristotle proposed the concept of the
unmoved mover [
6], a kind of primal force which gave the impetus for all later movements in the universe without having been moved itself. In Ref. [
1], an equilibrium between attractive matter and a repulsive cosmological constant or a scalar field was derived and introduced as initial state of
. Because this equilibrium is unstable, the transition to a temporal evolution is triggered by disturbances. This scenario exhibits important characteristics of an unmoved mover. The same applies to concepts by other authors: Hawking [
7] has defined the boundary conditions for a universe, described by a WKB approximation (see footnote 1), in such a way that a timeless initial state is created. Furthermore, there are many concepts for cosmic inflation, also including those in which the initial state is in an unstable or meta-stable equilibrium.
In this paper, the PS is derived by applying a WDW equation to a simple minisuperspace model. It is timeless, has only 3 spatial dimensions
1 and can (transiently) be considered as an unmoved mover,
unmoved due to its complete timelessness, and
mover, as it will turn out to be the cause of the creation of time, which is the prerequisite for the subsequent expansion movement. Aristotle probably has not taken into consideration that the unmoved mover itself is getting changed after the stimulation of movements (as the PS in our case).
2. It turns out particularly important to derive the WDW equation for the wave function
of the PS not in terms of the expansion parameter
a as usual, but of the corresponding volume
, because this reveals a structure of
which can be interpreted as the presence of space quanta. This has already been observed in Ref. [
5], where the case of a PS, consisting of very many space quanta, was formulated as a problem. Its more precise justification and elaboration constitutes an important part of this paper.
3. Another ingredient is the assumption that the space is uniformly curved and expands, which also pertains to concepts of e.g. Vilenkin [
8] – [
9], Linde [
10], Hartle and Hawking [
11], and Ref. [
12]. An important reason for this is that only such a space can have come into existence at some finite time in the past, while a Euclidean space has always existed, even if it expands. Our decision for a model of this kind is also motivated by the fact that everything observed in
and also
itself had a beginning.
2012 it was shown by a
global transformation of expanding space solutions of an FL equation, that the space expansion of
can also be viewed as an explosion in a non-expanding and almost Euclidean space [
2], in contrast to the general view since around 2000 at the latest. This interpretation was initially received with skepticism or even denial, but later it was devaluated as a matter of course, arguing that General Relativity (GR) would allow you to employ any coordinate system of your choice [
13]. However, this argument falls short as shown by the example of a coordinate system which rigidly rotates in conformity with the earth. Already from 27.6 times the distance between earth and sun the rotation speed exceeds the speed of light, so this coordinate system is unsuitable for describing a whole universe. Another example is the coordinate system commonly used (and also employed by us) for a uniformly curved, expanding space. This space expansion cannot be transformed away globally, because the matter flowing away from the explosion site in all directions would flow back after reaching the antipodean position and collide with the flow towards the latter.
2 This means that it constitutes a
generic space expansion, a property that will turn out to be essential for our model.
4. In our model, DE, the substrate of space, is needed for space expansion and information storage. It thus fulfills important purposes, which have already been discussed more detailed in previous work [
3,
4,
5]. That also provides the reason why DE is even present in
, observed as a gap filler for a significant energy contribution missing in the energy balance without it, and by an acceleration of
’s present expansion. DE can thus be considered as a fingerprint of the space containing
. In short
space-time is tied to the presence of DE and would not even exist without it, i.e. DE is space energy. As in the above papers, we assume that in the PS it is due to a cosmological constant
and has a huge mass density
close to the Planck density.
A further argument for our assumptions about DE is the following. Space is so weakly curved and therefore so extended that it reaches far beyond the boundary of
.
3 According to current knowledge, within
the DE is present and evenly distributed everywhere, also between the galaxies. It would be very strange if this distribution would stop at the boundary of
.
5. Physics describes the elements of matter through particles and fields and their temporal behavior through interactions between them. The description of the elements comprises properties that determine which of them interact, how strong the interactions can be and what type they are. However, this description is rather simple, using just a few parameters such as rest mass, charge, spin, etc. for particles, and scalars, vectors, tensors, etc. for fields. This is by far not sufficient to determine the temporal course of interactions which is regulated by much more complex laws of nature that the matter elements must obey. We know these laws together with the relevant mathematics and can use them to calculate whatever the matter elements do, but how do they know? As things stand today, they behave as if they had internalized the laws, i.e. they obey them as if they were following a categorical imperative [
14,
15]. Due to their relatively simple description, however, they lack the appropriate equipment. From a pragmatic point of view, one could be satisfied with being able to calculate everything necessary. However, we see a gap here that should be worthwhile closing. In this paper, we elaborate a proposal as to how this gap could be filled. To this end, working hypotheses are employed that cannot be taken from the known body of physics. Important ideas and preliminary work on this have already been presented in Refs. [
3,
4,
5].
Since the material elements are not “aware” of the laws of nature, the latter must be communicated to them externally. However, in this process it must be taken into account that material elements like an electron have no receiver, no brain and no power source to perceive instructions and convert them into prescribed actions. Our proposal in this regard was inspired by biology, where the molecules forming an animal or a plant are assigned their tasks by the genetic code written down in the DNA. Accordingly, we assume that all information about the laws of nature is encoded into submicroscopic structures,
information quanta, of very many space granules,
space quanta, constituting the timeless PS. (Laws on the storage and transmission of information must be included.) Presumably, this will not take the form we know, but rather the form of instructions on law-abiding actions. It follows that the volume of the PS must be very large to contain the huge amount of pertinent information. This leads to striking differences in the subsequent CS and quantum states
compared to the models studied in Ref. [
5].
6. The temporal evolution following the timeless PS consists in a generic space expansion as described above (see 3.). That this is not an auxiliary mathematical construct but a real physical process has a decisive meaning for our model. Unrestrained, the huge cosmological constant would cause a strongly accelerated space expansion and thus ever faster create new space elements, to which the information about the laws of nature must be transferred from the already existing ones. This requires a fixed amount of time, while the available time becomes increasingly scarce as the expansion rate increases. Obviously, this hinders the expansion, which we take into account in a lump sum by subtracting from the expansion acceleration a "friction force" proportional to the expansion velocity, as in our earlier work [
4]. It was left open there, how the information is stored. In this regard the present study makes a slightly more concrete proposal, which has similarities to how space quanta are arrived at in LQG, where group properties of polyhedra and a WDW equation are used.
3. Primordial Quantum State
Because of its extremely high mass density
close or equal to the Planck value
, the PS of the examined space-time system must be described by a general relativistic quantum theory, in our case a WDW equation. From this follows that
must be time-independent (see after Equation (
A3) of
Appendix A) so that Equation (
14) reads
In
Appendix A, the WDW Equation (
A4) with
is derived from this in terms of the dimensional quantity
V, and the substitution
in it yields the WDW equation (
A5) with
,
As in ordinary quantum mechanics, we interpret
(
since
is real) as a probability density, i.e.,
It cannot be localized at spots of one specific space, but it rather is a density with respect to contiguous volumes of independent spaces in the (virtual) ensemble (Hilbert space) of all theoretically possible spaces exhibiting the properties specified at the beginning of
Section 2.2. (We come back to this interpretation in more detail in
Section 5.1.5.) In
Figure 3 the probability density
is plotted for two solutions
of Equation (
18) to small initial values
and
specified later in more detail. It has zeros at essentially equidistant consecutive points and nearly equal maxima close to the centers
of neighboring zeros. The fact that
has practically the same shape in essentially all intervals bounded by adjacent zeros constitutes a crucial point of our model:
we consider in each of them as a separate quantum state in which the middle value
has the highest and each edge point has zero probability.
3.1. Inference on Space Quanta
From the last considerations it follows, that
v can only assume discrete values which on average differ by
. (In principle, with lower probability other differences from the interval
would be possible, but in order not to unnecessarily complicate our calculations, we use the most probable values
in the further course.) As explained in paragraph 5. of the Introduction, the volume of the PS must be extremely large for being able to store the information about all laws of nature. In Equation (
18) the second term in parentheses can be neglected against the first for
according to Equation (
36a), which is the case for almost all
v, given the large size of the primordial volume we find out later (
Section 5). Under these circumstances, Equation (
18) simplifies to
Of the two independent solutions, a suitable one is
where for the amplitude we could arbitrarily chose the value 1, because every multiple of a solution is also a solution. The probability density
has the period
, from which with
it follows, that for sufficiently large
v or
V resp. the most probable discrete volumes that the PS can assume are
with
(or
) is a small correction term in
v (or
V), which results from the fact that
is slightly larger for small volumes than for large ones due to the stronger influence of space curvature. For the numerical values the later result (
36a) for
was used. The (very large) volume on which we base the PS in our model is denoted by
where
,
and
where used for the approximations obtained in the last step. The exact value of
has yet to be determined. The
extent of the corresponding quantum state, the PS, is
from which follows that from
and from
according to Equations (
21) and (
23), at the upper boundary we get the boundary conditions
whereby, due to the extreme size of
we could assume without noticeable error that
is an odd integer.
From the discreteness of the possible PS volumes can be concluded that
(or
in dimensionless variables) is composed of elementary volumes whose average and also most probable size is
(or
). Because both the FL and the WDW equation employed for deriving Equations (
22) only describe space (via
) as a whole, a quantum structure of it can only become apparent through discrete values of the total volumes
V. This interpretation is also supported by the fact that the differences between neighboring discrete volumes of sufficiently large size are all the same. As an example, consider a stack of bricks of height
h. A stack of one brick has height
h, of two height
etc. If we only know the total heights
, we can regard the composition of bricks as a plausible hypothesis, see
Figure 2. Admittedly, our interpretation can only be assessed as an indirect proof.
4 However, any other interpretation of the discreteness of possible PS volumes (the “quantum staircase” shown in
Figure 2) makes no sense, and we will see that our interpretation leads to a coherent overall concept.
In the following, we will refer to
(or
) as the uniform volume of
space quanta of which
(or
) is composed, “uniform” for the sake of simplicity as already noted above. This simplification does not matter for most applications in this study, because – except for a rough determination of the primordial mass density
in the next section – we always have to deal with very large numbers of space quanta, for which only their average volume matters. (This is due to the fact, that differences in size and probability, which we are actually dealing with, cancel each other out in the sum.) However, at the end of
Section 3.2.1 we consider – if only qualitatively – the possibility of distinguishable space quanta that could turn out useful for the information storage so important for our model.
5 Numerical values for
and the corresponding extent
of the PS are derived in
Section 5.1.4.
3.2. Determination of the Primordial Mass Density
From Equations (
23) results with the definition of
in Equation (10c)
i.e. the size
of the space quanta is a function of the mass density
of the DE in the PS and is not fixed by the WDW quantization. However, by comparing solutions of Equation (
18) for different values
we will come to a choice that is acceptable although not stringent. It appears sensible to limit our search to the range where quantum and GR phenomena are equally important, from which it follows that
must be located in the vicinity of
. Accordingly, we must allow for the space quanta in the PS to be tiny black holes. In the next section, we want to roughly find out from which point on this is the case. For this, we content ourselves with a simple calculation, ignoring both quantum and GR effects. We then numerically determine the solution of Equation (
18) for different values of
or
resp. and decide which one seems most suitable for our purposes. The preceding rough calculation will help us to get a particularly illustrative picture of the space quanta.
3.2.1. Simple Black Hole Model
Not only for the simple model now to be considered, but in general we assume that the whole mass of space, i.e. mass of the DE that makes up space according to our model, is contained within the volume of the space quanta.
In the following more detailed calculations we restrict ourselves to space quanta forming non-rotating black holes and consider the entry point of black holes, at which the radius of a sphere of homogeneous mass density (
, see Equation (
33)) just coincides with the Schwarzschild radius
where
is a constant yet to be determined. From this follows with Equations (
1) and (2)
and with this the volume of the considered Schwarzschild sphere becomes
We assume that the Schwarzschild spheres of our black hole quanta do not penetrate each other, but touch in points and arrange themselves in the closest packing possible, the one claiming the smallest total volume. According to Ref. [
16], this means that the individual spheres occupy the part
of the the quantum volume
from Equations (
23), found without assumptions about the shape. Substituting the non-numerical part of Equations (
23b) and (
30) into Equation (
31) and solving for
yields
Under the natural assumption that there is only one black hole in each space quantum of volume
, the primordial mass density is
Inserting into this
obtained by resolution from Equation (10c),
from Equation (
23),
from Equation (
29), and
from Equation (
3), we obtain
and substituting this into Equation (
32) finally yields
With this, we get from Equations (
34) and (10c)
The fact that
is only about 1 percent of
indicates that our classical calculation for the mini black holes is not too wide of the mark. A numerical solution of Equation (
18) for this
is shown (
Figure 3) and discussed in the next section.
Besides the spherical black holes considered so far there are also rotating black holes. This opens the possibility to include space quanta with spin, that can have slightly different volumes (which is useful because our model allows for space quanta with different volumes). For massive objects with spin the quantum rules are well known and could be used for a different kind of loop quantum gravity (LQG) in a similar way as the polyhedra for the usual LQG [
17,
18]. In particular, space quanta with equal spin but different spin orientations could provide an alphabet for information storage.
3.2.2. Solutions of the WDW Equation for Different Values
When solving Equation (
18) numerically, we want to exclude, as with the analytical solution (
21), the case of a space with vanishing volume and would therefore prefer initial conditions such that
and
vanish for
. However, instead of zero, we have to take a very small value for
v (we chose
) in order to avoid
becoming singular.
must also assume a small value
in order not to get the solution
. Furthermore, we want to obtain solution (
21) for large values of
v. For this purpose, the initial value of
was chosen so that for large
v (about 20 times the largest
v in each picture of
Figure 3 and
Figure 4) the amplitude of
is 1.
In
Figure 3, the left picture shows the solution for
or
obtained in Equation (
35) of the last section. The dashed vertical line marks the upper zero
of the quantum state, which would result if it consisted of a single space quantum and would satisfy Equation (
23) derived for large
v. The horizontal line
represents the amplitude of the asymptotic solution (
21). For larger
v there is already good agreement. That there appear increasing deviations with decreasing
v is due to the fact that simultaneously the space curvature becomes more and more noticeable. According to our model the PS does not arise from a growth process, but is extremely large by definition and thus consists of a huge number of space quanta. This means that the different shapes and sizes of the quantum states with small
v have no influence on the space quanta within the PS with its huge volume
v, which are (indirectly) described by Equation (
23) and are all the same.
Figure 3.
Probability
, obtained from numerical solutions of Equation (
18). The dashed vertical line is at
size of the space quanta. Further details are provided in the main body.
Figure 3.
Probability
, obtained from numerical solutions of Equation (
18). The dashed vertical line is at
size of the space quanta. Further details are provided in the main body.
Even though the deviations from the asymptotic behavior at small
v do not play a role for a PS with large
v, it would be preferable if the quanta at small
v were at least roughly the same as those at large
v. This certainly does not apply to the case shown on the left in
Figure 3 due to the large gap of about
between
and the
v belonging to the first maximum of
. For this reason, we have examined a number of other cases which show that the situation improves with increasing
or
resp. The right picture in
Figure 3 shows the situation for ten times the value of
as in the left picture. The first quantum state still has slightly more than twice the extent
. In
Figure 4,
is again magnified by almost a factor of 10 to
. This situation is already almost optimal, and it has turned out that further enlargements (up to
) do not result in a complete agreement with
. We have therefore decided on the case
for all further calculations, which indeed constitutes a compromise. Since the value
is almost 100 times larger than the value at which, according to our rough calculation in
Section 3.2.1, the space quanta just become black holes, we can assume with considerable certainty that the space quanta, which we ended up with, are indeed black holes. According to classical GR it follows from this that they are mass points. Nevertheless, each of them requires the finite volume
. This does not imply that they have a structure, but simply means that they must be spaced apart according to their volumes. However, in correspondence to the classical rotation of black holes, they can still have a spin, which is relatively easy to handle quantum mechanically.
In
Table 1 the values of
,
and
are listed for the solutions represented in
Figure 3 and
Figure 4 and for volume quanta obtained in the LQG [
17]. (The value of
corresponding to the latter is calculated with Equation (
28)).
Given the uncertainties associated with each of the underlying assumptions, the results reported in the table are fairly consistent.
Figure 4.
Probability
, obtained from the numerical solution of Equation (
21) for
. The right picture shows the surroundings of the first maximum broadened in the v direction.
Figure 4.
Probability
, obtained from the numerical solution of Equation (
21) for
. The right picture shows the surroundings of the first maximum broadened in the v direction.
4. Evolution of Space-Time, Classic Treatment
In order for our model to describe a possible reality, we must assume that the PS is abandoned in favor of a temporal evolution. For this we first derive a classical solution of the momentum Equation (10), which is continuously connected to the PS. Why the transition from timeless to time-dependent comes about, i.e. why time emerges, is left open at this point, but will be dealt with in detail in
Section 5. When calculating classical quantities, we can leave it with the usual dependence on
x instead of
v, because wherever necessary we can use
to switch to the
v-dependent representation. Thereby nothing changes conceptually in contrast to what happens when deriving a WDW equation.
The classical evolution of space-time can be completely described by the solution of Equation (10) to the boundary conditions (
A7) and (
A8), which according to Equation (
A6) with (
A9) of
Appendix B is given by
After
Section 2.2, at this the FL equation (
9) is already fully taken into account. With
,
according to Equation (
36), and in anticipation of the later results (
54),
, and (
80),
, instead of Equation (
37) we can use with extremely little error the much simpler representation
where the upper sign, −, holds for
. From the comparison
of the two bracketed terms follows, that due to the extreme smallness of
we can write with extremely high accuracy
4.1. Determination of and Occurrence of a
Density Crash
Although Equation (
9) must no longer be taken into account, we can still use it to calculate
or
resp., i.e.
If we were to use Equation (
39) for calculating
, according to Equations (
9b) and (
40) the initial value of
in the CS would be
which contradicts Equations (
12a) and (
36b). In order to remove this discrepancy, for calculating
we must instead employ Equation (
38) to get
With Equation (
39) and the (very precise) approximation
follows from this
so we finally get
With this result the discrepancy disappears, because for
, neglecting
and
versus
(based on Equations (
36a), (
54) and (
80b)), we get
and from Equations (
9b) and (10c)
as required.
4.2. Classical Emergence of Time Accompanied by
a Huge Density Crash
For sufficiently large values of
, the second bracket term in Equation (
43) becomes negligible versus
, and we obtain
To find out more precisely when this is the case, we determine when
or
holds. This is the case for
with
where Equations (
1), (
4), (
36) and (
54) were used for the numerical values. After just
Planck times or
seconds resp., i.e. practically instantaneously
decreases from the huge value
to the much smaller value
(coming about due to
). This density decrease without equal represents a practically instantaneous and exorbitantly huge crash. Detailed reasons for its occurrence are discussed further down. It is particularly noteworthy that due to
the collapse of the density leads almost exactly towards the density
that results from the FL equation (
9) for the equilibrium
at
. The solution belonging to
(lower sign) even leads exactly to this point, because Equation (
41) results in
and
according to Equations (
9b), (
41) and (
43). In relation to our model, however, this is not an equilibrium, because from Equation (10) follows
for
. Because the solutions for both signs behave essentially the same, we further on restrict ourselves to that with the upper sign, i.e.
.
4.3. Determination of
We can now use Equations (
9b) and (
44) to calculate
by inserting for
today’s value
and resolving for
,
where
is the present value of
. Since in
, DE contributes 68.3 percent of the total mass density and the latter equals the critical density
with
present Hubble parameter and
present Hubble time, we have
Here,
was plugged in, a value that is slightly higher than the age of
, but slightly below the last values obtained from measurements for
. (This value was chosen because it yields a particularly handy result for
.) The value of
can be freely specified, but only above
due to Equation (
49). For illustration we relate it to the radius
(slightly below present the Hubble radius
) by setting
or
Inserting all this into Equation (
49), we get with
from which the condition
results for obtaining real values of
. For the space curvature to be below the maximum value compatible with measurements, according to Ref. [
19] the condition
must be satisfied. In
Appendix C it is shown, that in terms of our parameters this amounts to
. In
, the DE is usually attributed to a cosmological constant. Since the DE of our model is the substrate of space it should share this attribute, so we assume that at least during
’s present lifetime the density
of the DE is largely constant. For this reason we choose
still well above
. The value
seems sufficient to us and shall serve as a reference value. With this, due to
, we get from Equation (
52) with very little error
With the specification of
now also
can be calculated. According to Equations (
9b), (
39) and (
44) the further evolution of the density after its crash (i.e. for
) is given by
Characteristic values, calculated with this, Equations (
36), (
51), (
54), (
80) and
are given in
Table 2.
We are additionally interested in how the expansion rate
changes over time
t. For this we first calculate
and
for some times
. From Equations (
39), (
42), (
54) and (
80) we get
and
where the relation
, used for defining
, was employed to calculate
. For
Equation (
39) can be used for calculating
, and together with the above relationships, Equation (
62a), and
for
, we get the values given in
Table 3.
The values
corresponding to
are obtained from
so simply by multiplying
by the speed of light.
According to Equations (
57),
Table 2 and
Table 3, we have
(the = signs holding with high precision but not exactly), and due to
this state can be considered as start of the space expansion.
4.4. Causes of the Density Crash and Disequilibrium of the
Initial CS
The causes of the initial density crash can best be understood on the basis of Equation (
40). The values of the quantities on the right before and after the crash are given in Equations (
56) and (
57) resp.
must even be larger than the already rather large extent
of the PS (consisting of very many space quanta according to Equation (
89)) in order that
can assume the high primordial value
. (If it consisted of only one or a few space quanta,
would be almost zero, and then the term
in Equation (
40) would provide the required high density.) From Equations (
56) and (
57) follows that essentially
whereas
, i.e.
changes virtually not at all during the crash, while
changes by almost 62 orders of magnitude. In short, the huge extent of the PS in combination with the large initial value of
requires a large initial value of
(see Equation (
9a)), but both are pushed down nearly instantaneously by many orders of magnitude,
by 42 (see
Table 2) and
by almost 62 (see
Table 3).
The reason for the latter arises from Equations (10b) and (
A6b). Solving the latter with respect to
and taking advantage of the smallness of gamma we obtain
The high value of this friction coefficient combined with the high velocity
leads to the extreme friction force
against which the force
can easily be neglected. Equation (10) thus results in
The extremely fast change of
at
leads there to an extreme kink-like curvature of
.
The huge velocity at the initiation of the CS means that the space is in an extreme disequilibrium. Obviously, this affects the density much worse than an instability, where first a velocity or must gradually be built up. Now, from a classical point of view, the initial CS is the same as the PS, and one might assume that the latter is also in a disequilibrium and therefore decays. In the PS, however, time does not even exist, and hence the question of equilibrium or disequilibrium is irrelevant. Even so, we will see later that the density crash, initiated by the emergence of time, affects , the first of the quantum states to be derived later, in such a way that a huge increase in state probability comes about.
4.5. Age of Space-Time and Constancy of during U’s
Lifetime
To determine the age of space-time, we first obtain from Equation (
39)
With this and Equations (
1), (
51) and (
80) we get for the present age of space-time
For the reference value
follows from this
where
is the age of
.
Now we pursue the question of how it is about the required constancy of
during the lifetime of
. For this, using
we first go in Equation (
39) from
to a larger time scale in which the age of
becomes
. In this way we obtain from Equations (
9b) and (
44) with Equation (
39)
where for the numerical evaluation Equations (
54), (
62)–(
64) and (
80b) were used. If future measurements should show that the
per mil decrease in
found herewith is too much (or too little), our reference value of
could accordingly be adapted.
4.5.1. Universality of t, Irreversibility and Causal
Connection
As in the theory of U’s expansion, the time of our model is a measure of change. The mass density
of space (or of DE resp.) is a monotonically decreasing function of
t and thus provides the changes necessary to define a time. From the time
after the end of the density crash on,
or
resp. is given by Equations (
9b) and (
44). Substituting
from Equation (
39) and solving for
yields with Equations (
4) and (
9b)
is distinguished by the fact that it can be understood as a universal time, which can even be applied to different parallel universes. It is related to the coordinate system used in our model and can physically be characterized by the fact that in it, the DE density has the same value everywhere at any fixed time
t.
Due to the friction term in Equation (
7), the passage of time becomes irreversible, time is given an arrow in the forward direction. However, there is no major difference to the course of time in a universe described by reversible equations, which in many models also runs just in one direction without reversing. The only difference is that in our model, there is no solution traversing the same states backwards in time. Further below in
Section 7.0.3, we still take a closer look at the problem of irreversibility.
Table 3 shows that the present expansion velocity of space is
times the velocity of light. This makes it interesting to look at the observation horizon of space, given by
What is of most interest here is its relationship to the radial distance
which leads from a starting point to its antipode. For calculating the ratio
we use
,
,
and
(according to Equations (
54) and (
62)) and obtain
This means that from a fairly short time on, all space is causally connected. This result is of some relevance to the issue of whether traces of the existence of earlier and, like ours, expanding universes can be detected in
. For this it may matter that the space expansion of a universe can also be interpreted as an explosion [
2], whereby its boundary moves almost at the speed of light. That the boundaries of two universes are consequently approaching each other at a high speed can however only be concluded for relatively neighboring universes, because the ever faster expansion of space is a genuine space expansion that can only locally be transformed away. This shows again how important it is that the space expansion in our model is genuine, because without it the explosive propagation of universes would have long since led to unmissable collisions between
and other universes.
8. Discussion
Our model uses generally accepted equations of physics; an exception is only the introduction of a linear friction term into the cosmological momentum equation, but this is done in a way that the Friedmann-Lemaître equation keeps its full validity. In
Appendix F it is even shown that our classical solution for the CS satisfies the usual equations for a minisuperspace with a scalar potential
, rolling downhill in a simple parabolic potential
. The model proved surprisingly consistent in all the properties discussed. For many of them this could not be expected in view of the few assumptions used as an input, but rather came out as a result. One example for this is, that space-time is much older than
, another, that the probability of the
is extremely much larger than that of the PS, and still another, that the present number of space quanta is much larger than the number of atoms in
. But is our model also "correct" in the sense that it is as a whole or at least in parts actually realized? The answer to this question is not known, and it is even possible that our model is "wrong" in the sense stated. The reason for this is as follows: Physical equations have a manifold of distinct solutions, but many of them are not realized in the world we observe.
9 To make matters worse, it’s likely there is only one space-time, which reduces the probability that a correct solution for it is also the realized one. In the worst case, all that remains is the hope that questions posed and answered with our model make sense and are worth pursuing further.
An interesting results is the lightning-like huge crash, which initiates the emergence of time. In a way, it is the opposite of a big bang, because it prevents an expansion that starts with enormous speed. Also quite different from a big bang it does not develop from an energetic singularity, but from the very large, but finite energy of the PS. Unfortunately, one consequence of these differences is that, unlike the big bang, it leaves no trace that would be detectable today. (Note that the density crash of our model does not replace the big bang, but precedes it.)
One of our most important results and of central importance for the overall concept of our model is to interpret the solution of our WDW equation for the PS as an aggregate of
space quanta. It follows without any additional assumptions from our WDW equation alone, which differs from others in that the volume
is used instead of the scale parameter
a. It was already stated in Ref. [
5] - if only without conclusive proof. An indirect proof is finally provided in this paper.
Just as important as the quantum structure of the PS is that we also succeeded in quantizing the time-dependent classical solution of the CS, for which the friction term, caused by the inertia of the space quanta and by information transfer, plays an essential role. This resulted in a natural choice for the size and energy content of the PS, unprecedentedly large in terms of both. Furthermore, it also created the possibility of calculating a probability for the emergence of time, once again of outstanding size.
If the existence of space quanta with a volume claim similar to that of our quanta turns out valid, this raises doubts about the validity of various scenarios for the origin of
, which in a WKB approach extend the solution of an FL equation from real to imaginary values of time, then interpreted as a fourth space coordinate. In Refs. [
5,
8,
9],
emerges from absolute nothingness, its volume growing from zero to Planck size. In Ref. [
10], the volume of
attenuates from somewhat larger size down to Planck size in a kind of tunneling process. In cases of this kind, the fourth space coordinate is an arithmetic auxiliary for an actually time-dependent process. Not so in the no boundary proposal of Ref. [
7,
12], where the imaginary time as fourth space coordinate is twisted so that a timeless PS is created. The above mentioned doubts arise from two arguments: 1. The four spatial coordinates supposed to describe the PS of
all extend in the range of
and can therefore be covered by a single space quantum. The granularity of space is therefore far too coarse to provide the structure required for the intended purpose. 2. In the more advanced theories of quantum gravity, such as LQG, there is no imaginary time in the ground state of the quantum regime. As a result, the assumption of a fourth spatial dimension becomes obsolete.
The fact that Mach’s principle is not fulfilled by our model is almost self-evident. However, this does not mean that the discussion about its validity is over
Our model shares one problem with models about multiverses that contain parallel universes in addition to : At present there are no observations that allow to draw inferences about the results of the models. In question would be peculiarities at the edge of our observable universe, suggesting the existence of parallel universes via collisions with them. With our model, the decrease of the DE density predicted by it would be another way to check its validity.