Chapter VII

 

THE PROBLEM OF INFLATION

 

"The limits of science are like the horizon;

the more we approach them, the more they retreat. "

- Bacon -

 

     Initially physicists had supposed that the Big Bang would have occurred as a huge explosion that released an enormous amount of energy. But this explosion did not explain the existence of Uniformity subsequently verified by the cosmic background radiation. To justify this fact Alan Guth had the idea of introducing a new concept, the Inflation. This ultra-rapid inflationary expansion would be responsible to mix evenly all the Universe, producing as a result a very homogeneous distribution of matter. The theory of inflation is needed to explain the initial homogeneity of the Universe, otherwise the Universe would not have had enough time to standardize this uniformity padern. The era of inflation led to a strange form of the Universe, so that this period has raised many questions and is still waiting for some clarification. There are some concerns that a new period of inflation might happen again.

     Cosmologists seek to understand how come during the first fraction of a second of the birth of our Universe, immediately after the explosion of the Big Bang occur, the expansion of the Universe has achieved extremely high values, exceeding even the speed of light!

     During this period, the observable Universe, the very fabric of space and time, has greatly extended in much higher values than those calculated today on the expansion of the Universe. During the period of time that lasted for inflation, the Universe doubled in size every 10-35 seconds. Doubled up, so hundreds of times, expanding its volume at least 1050 times, while the temperature fell vertically, from 1028 K to 1023 Kelvin.

     Will we be able to explain the reason why this period of inflation had to happen? And also why it has ceased?

     Specific data show us that the period of inflation did not occur simultaneously with the explosion of the Big Bang, but a few fractions of seconds later.

     As you can see by this chart that shows the evolution of the radius of the Universe immediately after the Big Bang occurred, it appears to be that the initial explosion was, at the beginning, very regular and linear. It is after then, in a specific moment in time, that the expansion becomes inflationary, as we can see by this graphic:

- Inflation Era-

 

     This graphic of the inflation era show us the relation   between the radius and the temperature of the Universe …  I wonder what has unchained this inflation?!...

     This period might seem strange to understand. But, perhaps, it may not be so strange as we think ...

     Once again, based on the assumption that at the beginning of the Universe there were no Gravity Forces, that is, assuming that initially there would be no gravitational influence, thus the initial explosion would have started to expand in a regular way, but without any element of contraction exerted by any gravitational forces, this explosion would certainly expand continuously.

     Let us now make an analogy:

     When a gas is expanded, the relative density of the gas ceases to be constant, because the particles of this gas are redistribute as the volume increases. And the density, which means the amount of particles present per unit volume, is being increasingly smaller as the gas becomes more rarefied, more empty, until  is filled practically by vacuum.

     In the early expansion of the Universe there was a similar process. Removing this variable, the gravitational influence, the Universe was free to expand forever, at its free-will and very quickly. While the density was reduced dramatically, reaching a point where the density per unit volume was almost zero. If this expansion does not ceased, the barrier of zero is exceeded and the Universe reaches a negative density. This negative density leads to a very critical moment: This transition shows the power of the False Vacuum.

     Once the Universe enters and reaches this false vacuum, opens the door to an enormous amount of energy. It is this huge amount of energy that enters and unchains the inflation.

     But our Universe does not allow negative densities and therefore the repulsive energy of the false vacuum is unstable and decays very quickly. The door that was opened must be quickly closed. Once there has enter enough energy to restore a positive density, for values just above zero, the inflation ends, stopping automatically.

     The period of inflation lasted very little time, a few micro seconds ... fascinating!

     Track number 3: The absence of Gravity leads to negative densities.

     Cosmologists can be relaxed, there will probably be no more period of inflation in this Universe.