132
R. N. Mohapatra
Fig. 17.1 A pictorial depiction of inflation. The first jump in the picture is the beginning and end of inflation and the rest of the picture is Hubble expansion until today.
Source: Wikipedia.org
may be the best theory we have to understand the beginning of Hubble
expansion of the universe.
17.2 Beginning of the Hubble Era after Inflation
The next important milestone in the history of the universe is the time when
asymmetry between matter and anti-matter was created. There is a lot of
evidence in favor of the fact that the universe consists of only matter (protons,
electrons, neutrons) and no anti-matter (no anti-protons, positrons, etc.).
Cosmic rays contain a small amount of anti-matter that can be explained
by production from energetic proton–proton collisions in the space. There
is no other known place in the universe which contains anti-matter. In fact, if
there were anti-matter in as much abundance as matter (a symmetric universe)
close to each other, there would be annihilation and explosion, making the
universe completely empty of matter and full of radiation. If there was antimatter isolated in one area of the universe and matter in the other, then there
would be an asymmetry in the universe that should be reflected in the cosmic
microwave background observations. But no such asymmetry has been found.
The amount of matter in proportion to radiation is very small indeed—about
one part in a billion parts of radiation is matter.
R. N. Mohapatra
Fig. 17.1 A pictorial depiction of inflation. The first jump in the picture is the beginning and end of inflation and the rest of the picture is Hubble expansion until today.
Source: Wikipedia.org
may be the best theory we have to understand the beginning of Hubble
expansion of the universe.
17.2 Beginning of the Hubble Era after Inflation
The next important milestone in the history of the universe is the time when
asymmetry between matter and anti-matter was created. There is a lot of
evidence in favor of the fact that the universe consists of only matter (protons,
electrons, neutrons) and no anti-matter (no anti-protons, positrons, etc.).
Cosmic rays contain a small amount of anti-matter that can be explained
by production from energetic proton–proton collisions in the space. There
is no other known place in the universe which contains anti-matter. In fact, if
there were anti-matter in as much abundance as matter (a symmetric universe)
close to each other, there would be annihilation and explosion, making the
universe completely empty of matter and full of radiation. If there was antimatter isolated in one area of the universe and matter in the other, then there
would be an asymmetry in the universe that should be reflected in the cosmic
microwave background observations. But no such asymmetry has been found.
The amount of matter in proportion to radiation is very small indeed—about
one part in a billion parts of radiation is matter.