Interesting new article.
Here's a snippet:
We're getting something wrong about the universe. It might be something small: a measurement issue that makes certain stars looks closer or farther away than they are, something astrophysicists could fix with a few tweaks to how they measure distances across space. It might be something big: an error — or series of errors — in cosmology, or our understanding of the universe's origin and evolution. If that's the case, our entire history of space and time may be messed up. But whatever the issue is, it's making key observations of the universe disagree...
You can see that the edges of WMAP and CV SN overlap [see chart in article], mostly outside the red bar. That was the picture of the discrepancy a few years ago, Mack said: Significant enough to worry that the two measurements were turning up different answers, but not so significant as to render them incompatible with a little tweaking. But in recent years there's been a new measurement of the CMB from a group called the Planck Collaboration. The Planck Collaboration, which released its latest dataset in 2018, put very strict constraints on the mass fraction and expansion rate of the universe, denoted by the black sliver on the plot labeled Planck. Now, the authors wrote, two wildly different pictures of the universe emerge. Planck and WMAP — along with a range of other approaches to constraining H0 and Ωm — are all more or less compatible.