We know that after the big bang the temperature was about 10^32 K. But now the average temperature of the universe is about 4 K. What happened to the temperature at that time? Where did it go?
The Cosmic Microwave Background Radiation shows temperature differences. The red and yellow areas are warmer. The green and blue areas are cooler. For example consider this picture of CMBR ...
According to my measly understanding of the universe, when particles hit one another, some of their kinetic energy is transformed into heat. But when we heat particles (for instance, putting a bucket ...
How can it be that the beginning universe had a high temperature and a low entropy at the same time?
The Big Bang theory assumes that our universe started from a very/infinitely dense and extremely/infinitely hot state. But on the other side, it is often claimed that our universe must have been ...