Evidence of changing constants

3. Source: Hubble's law - Wikipedia

4. Source: The Hubble Hunter's Guide,
2019

5. Source: The Hubble Hunter's Guide ,
2019

6. Source: Blackbody Radiation – The Physics
Hypertextbook

7.  High-temperature recombination is an exotic solution that would require something like
time variation of the fine structure constant.
 Constraints in the CDM+ alpha model space have been studied.
 The constraints on the allowed variation of the ne structure constant are substantially
tighter than the variation that would be required to reduce the sound horizon by 7%.
 Although this is a specific model, we expect the result is general:
o the damping tail, which is highly sensitive to the history of recombination,
o and quite precisely measured, is not likely to allow solutions of this type.

8. See you all again next week !