The Big Bang theory is scientifically sound theory.

Definitions. From the Oxford Dictionary.Big Bang · “the rapid expansion of matter from a state of extremely high density and temperature that according to current cosmological theories marked the origin of the universe. A fireball of radiation at extremely high temperature and density, but occupying a tiny volume, is believed to have formed around 13.7 billion years ago. This expanded and cooled, extremely fast at first, but more slowly as subatomic particles condensed into matter that later accumulated to form galaxies and stars. The galaxies are currently still retreating from one another. What was left of the original radiation continued to cool and has been detected as a uniform background of weak microwave radiation” (sound) http://www.thefreedictionary.com...... 5.”Sound” “a. Based on valid reasoning: a sound observation.” “b. Free from logical flaws: sound reasoning.” sci·en·tif·ic (sī′ən-tĭf′ĭk) adj. “Of, relating to, or employing the methodology of science.” Keep in mind I do not have to prove the Big-Bang theory I must prove that it is a scientifically sound theory. P1.Overwhelming evidence. There is huge amounts of evidence and fulfilled expectations as I will describe. a)Large-scale homogeneity as expected. One of the many assumptions made in deriving the big bang theory from General relativity was that the universe is at a large scale homogeneous An example, consider the plot below showing galaxies from the Las Campanas Redshift Survey by Ned Wright. Each dot represents a entire galaxy! They measured both the position on the sky and the redshifts and translated that into a location in the universe. Think of putting down many circles of a fixed size on that plot and counting how many galaxies are inside each circle. If you used a small aperture then the number of galaxies in any given circle is going to fluctuate a lot relative to the mean number of galaxies in all the circles some circles will be completely empty, while others could have more than a dozen. On the other hand, if you use large circles the variation from circle to circle ends up being quite small compared to the average number of galaxies in each circle. This is what is meant by the universe is homogeneous. Here is the CMBR you can view the true homogeneity of our universe. b) The Hubble Diagram. The concept of a expanding universe is the notion that the distance between any two points will increases over time. One of the consequences of this t is that, as light travels through this expanding space, its wavelength is stretched as well. In the optical part of the electromagnetic spectrum, red light has a longer wavelength than blue light, so cosmologists refer to this process as redshifting. The longer that light travels through expanding space, the more redshifting that it will experience. Therefore, since light travels at a fixed speed,( 299 792 458 m / s) The big-bang theory tells us that the redshift we observe for light from by a far away object should be related to the distance to that object. The change in wavelength (either for sound or light) that one observes is due to relative motion between the observer and the sound/light source. An example for this is the change in pitch as a car approaches and then passes the observer as the car draws near, the pitch increases, followed by a rapid decrease as the car gets farther away. Edwin Hubble made a series of measurements at Mount Wilson Observatory near Pasadena, California. Using stars in a number of galaxies, Hubble found that the redshift roughly proportional to the distance. This relationship became known as Hubble's Law and sparked a series of theoretical papers that eventually developed into The Big-Bang theory. The only data that we have from the universe is light and using a combination of geometry physics and statistics, astronomers have managed to come up with a series of interlocking methods, known as the distance ladder, which is fairly reliable. The most striking example of this is the Andromeda galaxy, within our own Local Group. Despite being around 2 million light years away, it is on a collision course with the Milky Way and the light from Andromeda is consequently shifted towards the blue end of the spectrum, rather than the red. The upshot of this complication is that, if we want to measure the Hubble parameter, we need to look at galaxies that are far enough away that the cosmological redshift is larger than the effects of velocities. c) Abundances of light elementsThis is the Hubble Diagram showing nearly linear nature of the Hubblerelationship The big bang does not include the beginning of our universe. It merely tracks the universe back to a point when it was extremely hot and extremely dense. We have temperatures and densities high enough that protons and neutrons existed as free particles, not bound up in atomic nuclei. This was the time of primordial nucleosynthesis. So now we know that the expansion at the first few moments of time was dominated by radiation and some nuclear physics, cosmologists can make very precise predictions about the relative abundance of the light elements from this . Deuterium: for example was one of the elements produced As a result, deuterium that is produced in stars is very quickly consumed in other reactions and any deuterium we observe in the universe is very likely to be primordial. Looking at stars and gas clouds which are very far away thanks to the finite speed of light, the larger the distance between the object and observers here on Earth, the more ancient the image. So by looking at stars and gas clouds very far away, one can observe them at a time when the heavy element abundance was much lower. By going far enough back, one would eventually arrive at an epoch where no prior stars had had a chance to form, and thus the elemental abundances were at their primordial levels. We can also observe older stars, measure their elemental abundances, and try to extrapolate backwards. Like most predictions, the primordial element abundance depended on several parameters. In this case they are the Hubble parameter and the baryon density the dependence on both parameters is expressed as a single dependence on the combined parameter OmegaB h2 (as seen in the figure below, provided by Ned Wright). This figure implies this thus again verifies the theory also Second, independent measurements of OmegaB h2 from other observations like the WMAP results yield a value that is consistent with the composite from the primordial elements. The major pieces of evidence for the Big Bang theory are the consistent observations showing that, as one examines older and older objects, the abundance of most heavy elements becomes smaller and smaller. d) Existence of the Cosmic Microwave Background Radiation · The test of a theory is not that it meets one prediction. Instead, the true test is whether the model can match other observations once it has been calibrated against one data set. The cosmological origins of the CMBR comes from looking at distant galaxies. Since the light from these galaxies was emitted in the past, we would expect that the temperature of the CMBR at that time was correspondingly higher. By examining the distribution of light from these galaxies, we can get a crude measurement of the temperature of the CMBR at the time when the light we are observing now was emitted . They do agree with the big bang theory predictions for the evolution of the CMBR temperature with redshift. The state of this measurement is shown in the plot below. c) Age of stars Since the stars are a part of the universe, the big bang theory and our theories of stellar formation and evolution are correct, then we should not expect to see stars older than the universe. More precisely, the suggest that the first stars were "born" when the universe was only about 200 million years old, so we should expect to see no stars which are older than about 13.5 billion years.Which we do not. Conclusion. . The Big Bang Theory is a very well tested theory. A large quantity of data, coming from wildly different types of observations supports it. The primary set of parameters dictating the behavior of theory have been determined to a precision of 10% . While objections and alternative models exist, they are either easily disproved by the data or unable to explain the full range of the data as well as the standard picture. The Big Bang theory is scientifically sound theory.