Crisis in cosmology? Or just tweaking models?
Crisis in cosmology? Or just tweaking models?
I have read several articles like this one.
They all seem to be saying that there is a "crisis in cosmology", where different measurements can't reconcile what the value of the hubble constant is.
Then I watched this video last night that seems to be saying it's all just tweaking different models.
https://youtu.be/2pux7v9qJ58?si=ux3zBSHR-vvsz9qY
I'm not entirely sure if they're talking about two slightly different things. (Hubble's constant, and the predicted age of the universe.) Or if the "crisis" is really just a misunderstanding, or just clickbait tactics. Any informed opinions on the subject?
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For what I can tell, after the clickbaits and the sensationalisms, there is an actual unexplained discrepancy in the values of the Hubble constant measured with different methods. This means that something is not right in one of the methods (perhaps both), or that we are missing something else.
And yes, the Hubble constant is closely related to the age of the universe, so it's basically the same issue.
This is actually a good thing, because the "crisis" can be the first clue to discovering some new exciting science! Just look at how the "ultraviolet catastrophe" kickstarted the field of quantum mechanics a century ago
The video (you can skip to the last five or 10 minutes of it to get the gist of what I'm talking about) says that the discrepancy isn't unexplained. It's point is that the different models depend on a large number of variables, and one of those variables is the size and brightness of the first generation of stars in the early universe. Tweaking that part of the model can explain the discrepancy. (According to the video.)
OK, I've actually watched the video this time (the last part, as you suggested). It seems that the author decided to leave out the debate about the Hubble constant and talk about other phenomena in the early universe, which also have their uncertainties.
As far as I can tell, the Hubble tension is still a thing, and JWST only confirmed the measurements of the Hubble telescope. See for example this recent article on ars technica.