The Universe is ~13.8 Billion Years Old

There is absolutely no question that redshift correlates with speed: it simply stems from a Doppler Effect. Imagine a source that emits a wave, such as a sound. If the source is at rest, the wavelength will be constant (i.e. the distance between Wave A being emitted and Wave B being emitted is the same as the distance between Wave B and Wave C, and so on). However, if the source is moving, the wavelength will be contracted in front of the source and expanded behind it (i.e. the source emits Wave A, but it moves a bit before emitting Wave B, so in the direction of motion, there is less distance between the two waves, and more opposite the direction of motion). This is illustrated in the following diagram: There is no doubt this occurs: just go outside and listen to an ambulance or police car go by and notice how the pitch of the sound seems higher in pitch (shorter wavelength) when it is coming towards you and lower in pitch (longer wavelength) when moving away from you. It is also very easy to deduce that the amount by which the wavelength is altered in the direction of motion depends on both the speed of the wave and the speed of the source. Just imagine what happens if the source of the waves is moving as fast as the waves themselves: the waves would never get in front of the source. Light can behave as both a particle and a wave (1), so there is no reason for the Doppler effect to not apply for light as well. Just as a sound source moving towards or away from you sounds higher or lower pitched, a light source moving towards or away from you will appear bluer or redder. This requires no unbelievable assumptions, and the mathematics are relatively simple. Thus, the correlation between redshift and velocity is clear. We see no distant galaxies that are blueshifted, indicating motion towards us, which is very strange. This can be explained without violating the Copernican principle by the proposition that space itself is expanding (this would create the same perception of all the galaxies rushing away from you no matter where you are in the Universe). There are few explanations that do not require the Big Bang. I can think of one or two but they violate the Copernican principle and the odds of each scenario being observed the way we see it are one in billions, if not trillions: hardly likely enough to cast a 'reasonable doubt' on the Big Bang theory. I encourage my opponent to propose an model that would create the perception of no blueshifted galaxies for a reasonable fraction of galaxies in the Universe: the existence of such an alternative (assuming it does not assume our galaxy/the Local Group occupy a privileged position in the Universe) would be satisfactory for creating a 'reasonable doubt' of the Big Bang, but I remind my opponent that is not what we are debating. As for my opponent's concerns about the effects of the center of the galaxy (which is a strong radio source (2)) on measurements of the CMB, the solution is truly simple: wait until the Earth is between the galactic center and your detector and then take your measurements. Radio waves are relatively easy to block (have you ever tried listening to the radio in a deep tunnel?): a 12800-kilometer thick planet can surely do the job. When the Earth is between the source and the detector, a region where the interference does not exist is created around the detector, just as when the Earth is between an observer and the Sun (in other words, night), no light from the source is visible. A sidenote: the blackbody curve is a great approximation for most absorbers/emitters (3), and the CMB is no exception. Looking into the 'scientist' you referenced in your second source, his 'theory' is largely built on tearing down that basis. However, the theory of blackbody radiation stems from conservation of energy, so his work is based on trying to disprove the conservation of energy, the basis of all physics. That is generally a big red flag. My opponent's final concern is that radioactive decay is not constant. The video he cited was interesting enough, but I don't think the results the video announced (be them legitimate or not " the video seems rather sketchy) alter the validity of rhenium/osmium dating. According to the video, the variation - if it even exists at all - is periodic and miniscule. Thus the currently accepted half-life for rhenium is almost certainly close enough to the average decay rate that results taking the alleged variations into account would not yield a significantly different estimate than it currently does. There are a variety of methods by which similar estimates for the age of the Universe can be obtained, and they all operate on well-understood physics and mathematics. Given the remarkable coincidence of estimates and the fact that they are all derived completely differently leaves me unconvinced that we are missing something in our understanding of physics that is skewing any one estimate. Sources: 1. Davidson, Michael. 'Light: Particle or a Wave?' Florida State University, 1 Aug. 2003. Web. 14 Aug. 2014. 2. 'A Mystery in the Galactic Center.' NASA, 21 Feb. 2002. Web. 14 Aug. 2014. 3. Fowler, Michael. 'Black Body Radiation.' University of Virginia. 7 Sep. 2008. Web. 14 Aug. 2014.