No one knows whether it is right or wrong. However, since the mid-1960s, scientists feel that it is the best explanation at this time. However, does it explain the order in the universe and life within it?
Scientists know that the universe is expanding. By measuring the current rate, they believe that they know how long that this has been taking place. They feel that a giant fireball in the beginning created the ongoing expansion.
It is speculated that, at the moment of the start of the expansion, the universe was smaller than the nucleus of an atom. Then, the universe became a 100×109-degree inferno of rapidly moving subatomic particles. As all this expanded, it cooled so that these particles united into atoms of hydrogen and helium. Over the eons, these and other light elements collected into clouds. Many of these collapsed under their own gravity to form galaxies of stars and planets.
Steady State Theory:
The universe had no beginning, but always existed and will always exist. Stars are born and die, but the universe will remain virtually the same. The theory accounts for the expansion. However, it does not account for such phenomena as background discovered since the mid-1960s. The theory was abandoned in the late 1960s.
Plasma Universe Theory:
The universe has always existed, having a structure that is dominated by electricity and magnetism, not gravity. A state of matter called plasma is rare on Earth, but it does occur naturally in the near vacuum of space where there are electric and magnetic fields, for example, aurora borealis.
The universe’s electric and magnetic fields organize matter into galaxies and stars. The theory accounts for the vast ribbons of galaxy clusters in the cosmos. It also gives an explanation for the dark-matter mystery. However, it does not yet have observations to support it.