The finite speed of light was known before 1905. It was known by 1676.
Second, we see "big bang photons" in the CMB, but we're not seeing the big bang. We're seeing the glow from stuff at the time when the universe became transparent, that is, no longer a plasma.
The finite speed of light was known before 1905. It was known by 1676.
Second, we see "big bang photons" in the CMB, but we're not seeing the big bang. We're seeing the glow from stuff at the time when the universe became transparent, that is, no longer a plasma.