When we look up at the night sky we see darkness and numerous stars. Outside of Earth there is a vast and infinite structure. The universe is a large place and continues to expand. Astronomy,cosmology, and astrophysics have pioneered the exploration and study this beautiful and mysterious structure. It all began with an event known as the Big Bang, which changed everything.
The Big Bang is considered to be the start of existence as we know it. Matter, time, and space were born from the massive fireball (cosmic inflation)13.7 billion years ago. The earliest estimates of the Big Bang event can go as far back as 15 billion years ago. Not was matter created, but antimatter. Back then, the universe was high in temperature and dense. Gradually, the universe would decrease in temperature and expand. Edwin Hubble confirmed in 1929 that galaxies were moving further away from our own Milky Way Galaxy. This was done by examining the recessional velocities of stars that were red shifted. With an expanding universe more is left to be observed and discovered.
The universe has no boundary. There is no point in which one can reach the "end" of space. Even if a space explorer were to travel in the fastest ship, they would never find a border. The universe is isotrophic and would look the same in all directions. It would be difficult to distinguish one particular path from another. At one time cosmologists believed that the universe was static, but this was proven false. Olber's paradox states that if the universe were truly static, then the sky would not be dark.
The ultimate destiny of the universe has certain possible paths. An open universe will expand forever. A closed universe will expand and then contract in what is known as the Big Crunch. The universe could start an Big Bang and the cycle continues. As our understanding advances of particle matter, new knowledge becomes available. There could be not one universe, but many parallel universes. Multiverse theory could be credible. If there are antiparticles then it would not be impossible to say that another universe could be formed.
Further Reading
Couper, Heather and Henbest,Nigel. The Space Encyclopedia . New York: DK Publishing,1999.
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