There is something about the timeline of the Big Bang theory that has been bothering me for the past month or so. If you are vaguely familiar with the widely accepted theory of how our universe (multiverse?) got its start, you will know that according to theory, a lot happened in the first second.

My problem is with relativity - I cannot find a good explanation anywhere what 1 second means? Surely the mass of the singularity had to be insanely large - much larger than a typical black hole. We know from Einstein's theory of relativity that gravitational time dilation occurs near heavy objects. So is 1 second in the Big Bang theory measured from within the expanding singularity? It surely cannot be outside of it as spacetime evolved from that singularity; speaking of space outside of the expanding singularity is just nonsensical. So the "observer" had to be squished inside the expanding singularity, meaning if 1 second was relative to that location, that 1 second would not be the same as 1 second we experience here on earth. Not true? It had to be an eternity. Time is relative, is it not?