Big Bang Theory

Big Bang Theory

The Big Bang Theory is a theory which provides explanation about the origin of the Universe. According to this, the universe had started from a single point and gradually expanded during the next 13.8 million years in to cosmos. This theory was conceptualized by Georges Lemaitre in 1927. This theory explains the cosmic microwave background and the Hubble’s Law.  In 1929, Hubble observed that the galaxies were moving farther from the earth’s and the speed with which they were moving away was directly proportional to its distance from the earth. This observation later was known as Hubble’s Law. This theory makes two assumptions: physical laws are universal and the universe is homogeneous and isotropic on a large scale.

The most important evidences related to this theory are Hubble’s law which proves that the universe is expanding, the discovery of the cosmic microwave background and the observations related to the formation of the galaxy. According to Hubble’s Law, the light emitted from the distant galaxies is of longer wavelengths. This is also known as the redshift effect. The light emissions are isotropic and is uniformly distributed in all directions. In 1964, the discovery of the cosmic background radiation was made in the microwave background. Before the creation of this radiation, the universe was very hot and consisted of both energy and matter. Light could not escape from here as photons could not move freely. Slowly, the universe started cooling to a temperature of about 2.7 thousand degree Celsius. This enabled the formation of the hydrogen atoms due to the recombination of protons and electrons. The photons could move freely and this radiation was called the cosmic microwave background.  This discovery further provided confirmation about the predictions made by Big Bang Theory earlier. In 1970s, it was discovered that the wavelength of the cosmic background radiation was shifted to a longer distance due to the expansion of the universe. In addition, it was also evident that the universe consists of dark energy which speeds up the process of the expansion of the universe. This was another evidence to the Big Bang Theory. Gradually, the universe cooled down after expanding. During this process, few elements were created. These elements were Hydrogen and Helium. A detailed analysis of the observations suggest that after the Big Bang Theory, a number of galaxies and quasars were formed first followed by the formation of bigger structures like clusters of different galaxies.

Though there are ample evidences which are available to support the Big Bang Theory, there are some problems which the Big Bang Theory faces. The most significant problem is that this theory violates the laws of thermodynamics. According to the first law of thermodynamics, matter can neither be created nor can it be destroyed. Matter can only be converted from one form to another. This contradicts the Big Bang Theory, according to which the universe was created from a single point. This is not possible scientifically. In addition, according to the second law of thermodynamics, a tendency is present in the matter to move around. In contrast, if a Big Bang Theory really occurred, then particles of matter would have been present all around the universe and the planets would have not been formed. Another problem is that there is no proper evidence in relation to the existence of the dark matter and dark energy. Another problem is the magnetic monopole issue. A magnetic monopole is a small particle which contains magnetic charge and is electrically charged. If the Big Bang Theory really existed, then this particle would have been the most common particle which would have been found in the universe. However, this particle has not been observed according to the Big Bang Theory. Another problem is of flatness or the oldness problem. According to this, the initial density of matter and energy is of critical significance and any deviation could have had disastrous effects on the nature of the universe. So, if the universe had started off as a slightly positively or negatively curved, then the universe would have had positive or negative curvature according today. However, the curvature of matter and in relation to its density is quiet small. This implies that the chance that Big Bang created the universe which we know today is astronomically slim. Yet, another problem is the horizon problem. According to this, the universe it too big and it should have been formed more than 13.7 billion years ago. In addition, in Big Bang Theory, temperature is assumed to be uniform. This implies that matter should have moved faster than the speed of light to ensure uniformity. However, these assumptions are not valid according to Einstein’s Theory of General Relativity which states that nothing can travel faster than the speed of light.