origin of the universe

          All over world are the countless scientific theories that attempt to describe how the universe began.

          The most popular theory on the origin of the universe is the Big Bang theory. It states that at a specific moment in time, some 10-20 million years ago, there was an immense explosion. The explosion sent the particles moving outwards, which then cooled, condensed, and formed the universe, and until this .point of time he universe is still expanding.

          Another theory that explains how the universe came into existence is the solar nebular hypothesis. The idea behind the Solar Nebular Hypothesis is that the solar system was condensed from an enormous cloud of hydrogen, helium, and a few other elements and rocks.   Around five billion years this cloud of materials began to spin and contract together into a disk shape under their own gravitational forces.   The particles started combined together, protoplanets, to eventually form planets.   A great mass of the material eventually began to form together, protosun, and make up the sun. The Solar Nebular Hypothesis makes sense that 
gravitational forces of elements can begin to pull each other in and start spinning in a circle and sense there is less gravity in space that maybe why the planets are still rotating around the sun, which is logically in the center sense it is the largest in mass, even today five billion years later.

          The other theory that tries to explain about the origin of the universe is dust-cloud theory.  According to their dust-cloud theory, the solar system was formed from a slowly rotating cloud of dust and gas that contracted and started to rotate faster in its outer parts, where eddies formed. These eddies were small near the center of the cloud and larger at greater distances from the center. The distances corresponded more or less to the Titius-Bode relation. As the clouds cooled, materials coagulated near the edges of the eddies and eventually formed planets and asteroids, all moving in the same direction. The slowly rotating central part of the cloud condensed and formed the sun, and the sun's central temperature rose as gravity further compressed the material. When nuclear reactions eventually began in the suns interior, about 5 billion years ago, much of the nearby gas was blown away by the pressure of the sun's emitted light. Nevertheless the earthy retained an atmosphere consisting of methane, ammonia, carbon monoxide, water vapor, and nitrogen, with perhaps some hydrogen. In this primitive atmosphere and in the seas below it, organic compounds were formed that eventually resulted in living organisms. The organisms evolved in the next 2 billion years into higher plants and animals, and photosynthesis by plants and the weathering of rock produced the oxygen in the earth's atmosphere.

          These are just some of the theories that try to explain how it began. Even though there are evidences presented to prove their ideas, a lot of questions are still not answered.