Do you know what falsification is? Do you understand that you can't really prove anything, you can only disprove? (Excluding mathematics and logic that do not necessarily have to map to an actual reality) Do you understand that if they do their calculations and can say 'Ok, if we can look and see Y, that will prove BBT cannot be true, if we look and see X, that is consistent with BBT', that is *not* extrapolation? There's a model in quantum physics called the 'Minimal Supersymmetric Standard Model'. That model makes testable predictions - one of which is the mass of the Higgs boson, if such a boson existed (as it was not actually known for a while if it did - just that quantum physics predicted it should). Experimentation indicated a lower limit of the Higgs mass that was higher than the upper limit the MSSV predicted. When the Higgs boson was found, it had a mass of 125GeV. This is also above the Higgs mass the MSSV model predicted. So, question for you: Was that all extrapolation, or a falsifiable posit that was actually falsified? Given the data that the higgs boson has a mass of around 125GeV, is it reasonable to exclude the models that do not have lower limits below 125GeV and upper limits above 125GeV, while keeping those that do in the running, or not? AFAIK *no* potential model predicted CMB other than the BBT. That being the case, is it reasonable to say 'Ok, we'll go with that until we either find a better model or can falsify it', or isn't it? Prove the sun will come up tomorrow, without using any extrapolation.