Universe
Essay title: Universe
Two profound advances in our understanding of the universe date from the 1920s. One was the discovery that the universe is expanding, and that it is immensely larger than our Milky Way galaxy. The other was the revolutionary change from classical to quantum mechanics. The wider implications of these advances are still being explored to this day.
The Universe is expanding, seemingly at a uniform rate, the galaxies are moving back from each other and us. If we run the expansion backwards, we see that there must have been a point in time when all the matter of the Universe was together in an arbitrarily small volume; the occurrence that created our Universe is known to the world as the Big Bang. The Big Bang is the scientific theory that the universe emerged from an extremely dense and hot state about 13.7 billion years ago. At the point of the Big Bang, the universe was substantially dense and unbelievably hot. Just after the big bang, atoms and subatomic particles in a super-dense state were torn apart from each other. If nothing except an outside force acts on these particles, they will continue to expand indefinitely. Even after billions of years, we can still see the effects of this explosion. In 1922, Alexander Friedman discovered the first evidence of an expanding universe. Edwin Hubble established these findings in 1929 when used the Doppler Effect to good use. This was soon after Einstein made a mistake by applying the theory of relativity to the structure of the universe. Hubble showed otherwise. The Doppler Effect simply states that travelling waves will have different frequencies depending on the direction of the object. Hubble in turn used this principle to develop the ‘law of red shifts’. Hubble found that galaxies are moving away from us in all directions. As time moves forward, the universe is growing apart. So what this basically means is that if some one actually decides and succeeds in making a time machine and they travelled back in time, the universe would be getting smaller and smaller. The conclusion that he (Hubble) came to was that the universe is expanding in a uniform fashion. When this process is reversed, it is clear that all galaxies in the universe converge to a single point and this is