Science

The redshift is tied to velocity but distance can be measured with the “standard candle method” where a “standard candle” is a star/body that we know the size and distance of. I don’t remember/understand the specifics of how a standard candle comes be (telescopes I guess?) IIRC they use a bit of trigonometry along with the flicker rate/brightness to find the distance of bodies.

So they have a way to measure the distance completely independently of how they measure velocity (redshift/blueshift). Those values didn’t match up but the distance between bodies was observed to be constantly increasing across the board which is why they came to the expansion conclusion.