Reply to post: There's a third possibility

There's a third possibility

The rate of expansion hasn't been constant throughout the history of the universe. Some theories of the Big Bang pretty much require a period of really fast inflation in the first few moments, but even ignoring that there's no reason to assume that the rate of expansion today is identical to the rate of expansion 6 billion years ago. Especially if our universe is part of a bigger metaverse, and energy from the 'outside' influences our expansion.

If the rate of expansion isn't constant, then it makes sense that the constant calculated via the cosmic background radiation (which basically measures the rate of expansion at what 750,000 years of age of something like that?) and the rate calculated using Type Ia "standard candle" supernovas at varying distances and the rate calculated by measuring gravity wave events like neutron star or black hole mergers.

So I'm not sure they should reject the calculation of one method as "wrong" merely because it doesn't agree with the answer achieved using another method.