Section 1 of Chapter 2:
The driving force in our universe
Another interpretation of the second law of thermodynamic
We all agree that what we see in the sky is the result of billion of years of
evolution. It was not like this at the very beginning. Science explain to us
that what we see is the result of a long process of transformation of the primordial
energy. Thus we acknowledge that at the beginning we have to imagine an enormous
amount of energy, and thus we ask ourself WHY did this energy starts to transform
itself into the universe that we see today.
The answer is very simple: nature is striving toward stable states!
Having energy at disposition means that we have many possibilities to
use (transform) it.
If those possibilities exist, then the present state is not stable.
The important point now is to understand that the transformation of energy
in its different forms need a space, i.e. our tri-dimensional space. This did not existed
before the Big-Bang event: only at this initial time the tri-dimensional space started
to be built, and it is still building up now, as the mouvement of the galaxies around us
shows.
We have to suppose that the building of space need energy. Thus some of the primordial
energy was (and still is) used to create the thre-dimensional space which is our
universe. Yes, I do not have any proof. It is just a theory which is based upon the
analogy with the electromagnetic field: if we use energy to separe two charges of
equal amount but opposite sign (positive and negative) then a dipole field arise,
and we need energy to build this field which then shows a well known energy density.
Why should "space" be different? The gravitational field is
our space!
In fact the laws for gravitation and electric field are so similar!
The magnetic field can be seen as a relativistic effect of an electric field for
moving charges.
At the very beginning, the density of energy was so high that only the basic
particles could survive. But then more space was created, increasing the volume of the
infant universe, and the energy density diminished (the universe cooled down) then the first
atoms could survive and finally we have the building of the first element: hydrogen.
We have to understand that striving toward stable states does not mean simplicity!
The opposite is true: in binding energy into more complex constructs we reach a better
stability, as
the primordial energy is getting bound and cannot transform itself into anything else.
This is a very important fact which help us to understand why life did come out of
matter. See for example: "What is Life" by Addy Pross, Oxford University Press 2012.
The steps of the evolution are all related with the two laws of thermodynamic.
The first law tell us that energy will only be transformed, never annihilate.
Of course it does not say where the primordial energy comes from.
And it does not say if there is still a stream of new energy flowing into our universe.
Another point to consider is that we do not really known what a "field" is:
in fact we only can detect the effect of its presence.
Maxwell's equations perfectly describe the effect of the
electromagnetic field, but nobody can say what this field
really is. Einstein's relativity perfect "describes" how gravitation works,
but not was gravitation really is (well, that the "God"
particle (the Higgs Boson) can explain gravitation is not good enough for me)
But my interest here is to the description of the second law of thermodynamic,
which is explained using the entropy, and which I would like to
explaine using a kind of inverse of it.
One can find many definitions and descriptions of this second law. One is the following:
The "entropy" of the universe tends to a maximum ==> energy spreads out
over time, resulting in an increase of entropy. And this is often described as an
increas of "disorder".
Another description is:
Entropy counts the number of microstates per macrostate. A microstate is
the exact definition of the state of a system. A macrostate is an average over many microstates.
Entropy is a measure for how likely a system is to be in a certain configuration:
S(entropy)= k * ln(OMEGA) where k=Boltszmann's constant and OMEGA is the number of
microstates.
I find all those description of the second law not much helpful for its understanding.
But at first I would like to emphasis, that it is more a statement about the
PROBABILITY that an event happen, thus it does not forbid that
the entropy may locally be decreased, which in fact happen necessarily to sustain life.
But I think that we would better explain this second law thinking of the fact that
nature strive toward stable states.
Let think about it: if we have a lot of energy at our disposition, then we can
do many things. Having such a high number of possibilities to use this energy means
that this situation is unstable.
Thus nature will try to "bind" energy in order to have a stable state.
We see this in the evolution of the universe: the initial primordial energy is
very unstable, as it can be used for many things. The first possibility has been to
use this energy to create the three dimensional space in which we are in. And this
is a process which is going on even today: we see the galaxies going away from us
not because of some kinetic energy given by a Big Bang, but because between us and
them new space is created continuously.
And at the very beginning the use of energy to create space was the only possibility
in order to reduce the density of energy. When the space was big enough that the density
of energy was lower enough (we could say "lower temperature" but there were
no particles and thus no kinetic energy to define temperature) for the first building blocks
of matter to appear. Later on we had electrons, protons and neutrons.
And now: one way to bind the primordial energy was the building of
a structure: the atoms (hydrogen). May be helium too, which bound energy necessary to
keep two proton together. Now that we have particles around we can speak of temperature.
And the high temperature kept the atoms from clumping together. In the meantime the
space increased in extension and the temperature (the density of energy) decreased to
a level where the weakest of all forces could act: gravity!
The rest of the story is well known: stars, galaxies, super-nova, new elements,
planets.
But all this is going on while if energy is around "unused" then this
is a unstable state.
Work in progress .... sorry about that, be patient please.
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