Lesson 13 – What Scientists Currently Know About the Big Bang, The Expansion Of The Universe, & The Existence Of The Purposiveness

“Science is a way of thinking much more than it is a body of knowledge”

Carl Sagan
Cosmologist

The Big Bang & Science

In the first few minutes, the universe was filled with an enormous amount of radiation which would have prevented the formation of too much of the heavier elements (helium, etc.).  The expansion of the universe since then would have lowered it’s equivalent temperature to a few degrees Kelvin so that it would appear now as a background radio noise, coming equally from all directions.

Radiation consists of particles called photons.  An ordinary light wave contains a huge number of photons traveling along together, but if we were to precisely measure the energy carried by this wave, we would find that the energy contained by it is always some multiple of the energy of a single photon.

Before the universe was sufficiently transparent enough for photons to travel for an appreciable fraction of the age of the universe, without being scattered or absorbed, there was a period of maybe 700,000 years when the contents of the universe were so hot and dense, that they could not have yet clumped into stars and galaxies.  Nuclei and electrons which were to make up atoms had come into existence, but the atoms themselves had not.

This period could be called the “radiation-dominated” era of the universe.  Here, a photon of light could not travel immense distances without hindrance, as it can in our present universe.  During era, a photon would find in its path a huge number of free electrons which could efficiently scatter it or absorb it.  If the photon is scattered by an electron, it will generally either lose a little energy to the electron or gain a little energy from it, depending on whether the photon initially has more or less energy than the electron.

Thus, although in a sense the universe was expanding very rapidly at first, from the viewpoint of an individual photon or electron or nucleus, the expansion was taking a long time, time enough for every particle within it to be scattered or absorbed or reemitted many times as the universe continued expanding.

At some point in time, where many individual particles have time for many interactions, it is expected that they will come to a state of equilibrium – the numbers of particles with properties (such as position, energy, velocity, spin, etc.) in a certain range will settle down to a value such that an equal number of particles are knocked out of the range every second as are knocked into it.  Equilibrium doesn’t imply that the particles are frozen, each one is continually being knocked about by its neighbors, rather it is statistical – it is the way that particles are distributed in position, energy, velocity, spin, etc. that does not change, or changes slowly.

Equilibrium of this kind is “thermal equilibrium” and is always characterized by a definite temperature which must be uniform throughout the system.  The universe has already passed through a state of thermal equilibrium.

There was once a time when the universe was so hot and dense that atoms were dissociated into their nuclei and electrons, and the scattering of photons by free electrons maintained a thermal equilibrium between matter and radiation.

From this time and on, since the universe was transparent and individual photons would not be created or destroyed, the wavelength of any individual photon would also simply increase in proportion to the size of the universe.

During the “matter-dominated” era, radiation was able to expand freely.  The background photons and the nuclear particles have been neither created nor destroyed (their ratios remain constant).  (This ratio was roughly constant even earlier, when individual photons were being created and destroyed)

The differentiation of matter into galaxies and stars could not have begun until the time when the cosmic temperature became low enough for electrons to be captured into atoms.

The gravitational force within any nascent clump increases with the size of the clump, while the pressure does not depend on the size.  Hence at any given density and pressure, there is a minimum mass which is susceptible to gravitational clumping.  This mass is proportional to three-halves power of the pressure.

In order for a clump of matter to form a gravitationally bound system, it is necessary for it’s gravitational potential energy to exceed it’s internal thermal energy.

Just before the electrons started to be captured into atoms, at a temperature of about 3000 degrees Kelvin, the pressure of radiation was enormous and the Jean’s mass was correspondingly large (about a million times larger than the mass of a large galaxy).  Neither galaxies nor even clusters of galaxies are large enough to have formed at this time.  However, a little later, the electrons joined with nuclei into atoms.  With the disappearance of free electrons, the universe became transparent to radiation and so the radiation pressure became ineffective.

At a given temperature and density, the pressure of matter or radiation is simply proportional to the number of particles or photons, respectively, so when the radiation pressure became ineffective, the total effective pressure dropped by a factor of 1,000 million.  The Jean’s mass dropped by the three-halves power of this factor, to about one-millionth the mass of the galaxy.

From then on, the pressure of matter alone would be far too weak to resist the clumping of matter into galaxies.

The enormous energy density of radiation in the early universe has been lost by the shift of photon wavelengths to the red as the universe expanded, leaving the contamination of nuclear particles and electrons to grow into the stars and other components of the material world.

How We Need To Interpret This Evolutionary Process:

With the birth of the universe, the galaxy, and the matter that Creation used from there forward, Spirit descended further into the material world until inorganic and organic molecules where created. Between those two realms (in the 4th kingdom of Creation here on Earth) lies the Turn – a turning point where life moves from using the rational logical mind to learning to utilize instead, the intuitive promptings of The Purposiveness that created everything. Our goal as human beings at this time is to make it through the Turn. Our evolution has taken a huge amount of time for Creation to go from the first moment of the Big Bang to where we are now – containers for the consciousness of The Purposiveness.

Where we are now is a privilege and an opportunity for change. Use it well since there is only one time during the entire evolutionary process where we can manifest within the period of time that I call The Turn – and that time is now!