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Is the Universe Younger than We Thought?
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October 15th 19, 09:53 PM posted to sci.astro.research
Phillip Helbig (undress to reply)[_2_]
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Is the Universe Younger than We Thought?
In article ,
(Steve
Willner) writes:
Two additional preprints are at
https://arxiv.org/abs/1907.04869
and
https://arxiv.org/abs/1910.06306
These report direct measurements of gravitational lens distances
rather than a recalibration of the standard distance ladder.
The upshot is that
the discrepancy between the local and the CMB measurements of H_0 is
between 4 and 5.7 sigma, depending on how conservative one wants to
be about assumptions.
"New physics" could be something as simple as
time-varying dark energy
Now THAT'S an understatement! :-)
Also interesting on this topic: arXiv:1910.02978, which suggests that
the local Cepheid measurements are the odd ones. arXiv 1802.10088
re-analyses data on one lens system, resulting in a slightly longer time
delay and hence slightly lower Hubble constant, i.e. making this
particular system more consistent with the CMB value. Steve mentioned
how long the modelling takes. A modeller has the input data, though;
there is a huge amount of work just to get that far as well: observing,
reducing the data, and so on.
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