[netcraft]

I've always thought as a layman that the weakest link in all of this is our cosmic distance ladder, seems like the most likely place that errors would stack up and lead us to some wrong conclusions. So may places for things to go wrong, we make a lot of assumptions about type 1a supernovas actually being a constant brightness, dust obscuring our view of them, plus all of the assumptions we've made about even measuring the distance between the ones we've measured. And its not like cosmologists havent acknowledged this, but I think a lot of the hubble tension might be solved once we figure out how to measure these distances more accurately.

[db48x]

The error bars on those distances have been shrinking for decades. Slow steady progress.

[bonzini]

... And for completeness, the shrinking actually made the tension worse.

[jug]

Until now with a far better telescope able to significantly improve the sample size, that is.

Ugh, this is so frustrating. We know our current theories cannot be complete but the LHC has mostly just confirmed assumptions, and now this. Everything seems to well contained.

[dvh]

Which is exactly how systematic error would manifest

[db48x]

It would have to be a pretty robust error to survive 30 years of continuous study.

[hnaccount_rng]

Or a common unchallenged assumption. Orthodox errors are always only obvious in hindsight

[sandworm101]

The various candles are not independent yardsticks, nor are they just assumed to be true. Wherever possible they are compared against each other. And there are people who spend entire careers debating how dust absorbs light in order to best compensate for such things.

If measurements point to some sort of incongruity, questioning the accuracy of one's ruler is a fools trap. Altering the rulers to remove incongruities results in a spiral of compromises, internal debates that don't result in progress. If one suspects that the rulers are wrong, the answer is to build a better ruler. Not to arbitrarily chop bits off until the difficult observations go away.

[netcraft]

I totally agree, hope my comment didnt come off to the contrary. As a layman, I consume most of my information through popsci sources (though I try to go more for the Dr. Beckys than the meatless or sensational stuff), and its generally described as something that we just take for granted - "we just found the oldest galaxy ever observed, only a few hundred million years after the big bang - and its too bright and has way more 'metals' than expected" - but we measured that with redshift, which makes a bunch of assumptions that of course they cant talk about in every video, but we dont talk about anyone questioning them.

I have no doubt that there are great scientist spending their entire careers trying to improve these rulers and measurements, but I also know that there are great scientists spending their entire careers basing everything on the best rulers they have...