Question

Write a short note on the universe and its existence.

Answer 1

Universe is all the matter and energy that exists or ever existed in our knowledge. The study of the universe is called cosmology. The scientists who study cosmology are called cosmologists.

Complete answer:
Everything that ever exists in our dimension means each person, each planet, each star and each galaxy is a part of the universe including the empty space. Universe can be defined as everything that exists. The word universe describes all of the things that exist. The universe is too vast, in measure of light years; it will take like 15 billion years to reach to the other end of it as far as we have interpreted from our knowledge.

The universe has been created or started existing about 12 - 15 billion years ago, due to the big bang as we know. According to the theory that has ever been thought of, the Big bang was a gigantic explosion which created all of the mass and the energy in the universe in less than a second. The big bang was extremely hot; it was around ${10^{27}}{}^ \circ C$ . The after effect of the big bang is so huge that our universe is still expanding. Scientists who study the universe are called cosmologists.

Note: Some of the cosmologists believe that at some point the universe will shrink back again to a state of high temperature and density. This theory of the shrinking of the universe is called the big crunch. It is the contrast to the Big Bang. In contrast to that some of the cosmologists think that gravity will keep expanding the universe and it will keep expanding as it is.