Re: You have nothing...
If the speed of light had ever changed in the past then metabolism would have been rendered impossible.
The speed of light being constant has a much broader consequence than just measuring vast distances and ages.
The Big Bang actually matches what was stated in the Holy Bible thousands of years before a modern epithet was placed upon it.
Interesting perspective here on light and metabolism indeed, however that only just proves light can in fact be bent, slowed, stopped, and sped up and that this occurs in great variety every single day even today. It's as simple as observing the difference between a cloudy day and a clear sunny day and how the plants and animals somehow still grow (in fact some organisms do not even need sunlight to metabolize.)
As for Big Bang, nah that theory is bunk. Magical dot the size of a hydrogen atom explodes and forms the universe? I don't buy that. Also if that were true the universe ought to be perfectly spherical along with all the pieces and parts within it (at least originally until catastrophic events would occur breaking them), yet we find no trully perfect spheres anywhere in the cosmos. Why are there more elements than just hydrogen in the Universe if the universe originates from a hydrogen atom? In fact why are we discovering new elements still today? Also the unfathomable amount of light and heat generated from the Big Bang should theoretically still be visible, yet it is not. Also for those that do play by the logic of the BB there is some major disagreement over whether the universe is still growing or is now contracting (big crunch theory). Most honest answer is they just have no idea lol. I think Big Bang is currently in the process of being embalmed and prepared for burial because despite the heavy indoctrination of this theory, most people just don't buy it due to too many problems with it, and those that do buy it can't agree which Big Bang ist he right Big Bang lol. Which is why scientists are coming up with all sorts of other theories like String Theory, multiple dimensions, multiverse theory, etc.
Really though the two questions that discreditted the Big Bang for me most even when I was a staunch atheist are: where did this mystery big bang atom originate, and through what medium is it moving?
I am heading out for a bit so sorry if I do not get to any response to you too quickly. Very stimulating conversation/debate though! Lol, you might be an old man but you'd fit right in with me and my friends, we like to hang out and just talk over theories a lot from Big Bang to Politics to the Bible lol. Lol so I am not trying to sound hostile to you or nothing, I in fact enjoy your input even if we disagree. I just like talking theory and why theory is wrong or what in the theory is right, etc.