Practical Report: Big Bang Theory
Year 10 Science
Practical Report
Big Bang Theory
Introduction
According to the scientific community, all the matter in the universe began in a very tiny, hot and compacted point. But what exactly caused this point to become the universe we know today? The “big bang” theory is the popular explanation for where the galaxies, stars and planets came from. At the moment of the big bang, the hot, compact point began expanding like a balloon, rather than an actual explosion like most people believe. As the point of matter expanded, it cooled, contracted and formed stars and galaxies, like our solar system and the Milky Way. This suggests that big bang explains the expansion of space itself, which in turn means everything contained within space is spreading apart from everything else (refer to diagram below).
Space and time, according to scientists like Steven Hawking, George Ellis and Roger Penrose, were created after the big bang. These three scientists performed mathematical calculations to help prove their ideas in the 1960 's and 1970 's. Many years earlier in 1929 Edwin Hubble, an astronomer working at the Carnegie Observatories in Pasadena, California, measured the distance between galaxies using Cepheids, a type of variable star. By observing the light spectrum in these galaxies, he discovered that the light was distorted in a way known as “red shift”. This meant that the light rays were longer, and appeared redder than expected. When Hubble plotted redshift against distance, he found that the redshift of distant galaxies increased as a linear function of their distance. The only explanation for this observation was that the universe was expanding.
Scientists believe that since the Big Bang the universe has been constantly expanding, but the rate at which is it expanding is unclear. The big bang theory remains a theory because the evidence available only traces what we can see from our place in the universe back through time, which could be
Practical Report
Big Bang Theory
Introduction
According to the scientific community, all the matter in the universe began in a very tiny, hot and compacted point. But what exactly caused this point to become the universe we know today? The “big bang” theory is the popular explanation for where the galaxies, stars and planets came from. At the moment of the big bang, the hot, compact point began expanding like a balloon, rather than an actual explosion like most people believe. As the point of matter expanded, it cooled, contracted and formed stars and galaxies, like our solar system and the Milky Way. This suggests that big bang explains the expansion of space itself, which in turn means everything contained within space is spreading apart from everything else (refer to diagram below).
Space and time, according to scientists like Steven Hawking, George Ellis and Roger Penrose, were created after the big bang. These three scientists performed mathematical calculations to help prove their ideas in the 1960 's and 1970 's. Many years earlier in 1929 Edwin Hubble, an astronomer working at the Carnegie Observatories in Pasadena, California, measured the distance between galaxies using Cepheids, a type of variable star. By observing the light spectrum in these galaxies, he discovered that the light was distorted in a way known as “red shift”. This meant that the light rays were longer, and appeared redder than expected. When Hubble plotted redshift against distance, he found that the redshift of distant galaxies increased as a linear function of their distance. The only explanation for this observation was that the universe was expanding.
Scientists believe that since the Big Bang the universe has been constantly expanding, but the rate at which is it expanding is unclear. The big bang theory remains a theory because the evidence available only traces what we can see from our place in the universe back through time, which could be
Bibliography: The Big Bang Theory. (2009, March 7). Retrieved Feburary 8, 2013, from howstuffworks: Science: http://science.howstuffworks.com/dictionary/astronomy-terms/big-bang-theory1.htm Origins of the Universe: Science behind the Big Bang Origins of the Unvierse. (2010, June 12). Retrieved Feburary 8, 2013, from National Geographic: http://science.nationalgeographic.com.au/science/space/universe/origins-universe-article/ The Big Bang Theory Science behind the Big Bang Theory. (2012, April 17). Retrieved Feburary 8, 2013, from BBC: Science: http://www.bbc.co.uk/science/space/universe/questions_and_ideas/big_bang/ (2012)