Not a PhD

It is a result of the red-shifting of light from distant objects, because of the expansion of the Universe. You can read about the red shift in the first part of this answer:  Ilavenil Surya Thirumavalavan's answer to How scientists measure the age of light coming from stars? After the Big Bang, there were various stages in which the Universe expanded and cooled. First the elementary particles formed (quarks, electrons, etc.) and then came the subatomic particles (protons and neutrons.) This was very chaotic, as particle-antiparticle pairs annihilated continuously. The light that was emitted would traverse a very short distance before it hit another particle, and would scatter. At a certain stage in the very early Universe (377000 years later, but we’re talking about something that happened 13.6 billion years ago) the temperature of the Universe dropped enough for protons and electrons to form the first hydrogen atoms (shown as the Era of atoms in the above di...

I think you are asking about the early stages of the Universe in which there was a slight imbalance of matter over antimatter. The reason for this is not known, in fact it is one of the greatest unsolved mysteries in Physics. Today’s Universe is dominated by matter only because of that imbalance.

The concept of “Wormholes” came about this way: Einstein published his description of Space is in the form of “Field Equations,” in 1915. They are given below. The equations involve tensors, so the above line is actually a way of representing a number of partial differential equations. A solution of these equations will give a mathematical model of space-time. Over the years, many people have worked on these equations. Any solution of the Field Equation will start with some assumptions. One of these solutions is the Schwarzchild metric, published in January 1916 (Just over a month after Einstein published his equations). The metric describes the gravitational field outside a spherical mass, with the assumptions that the angular momentum and electric charge of the mass are zero. One of the implications of the Schwarzchild metric is the existence of black holes. This is because at r=0, the curvature of space time becomes infinite, and the nature of the gravitational field c...