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Jim1348

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Message 21621 - Posted: 11 Jan 2018, 22:58:10 UTC

A mathematical discrepancy in the expansion rate of the Universe is now "pretty serious", and could point the way to a major discovery in physics, says a Nobel laureate.

The most recent results suggest the inconsistency is not going away.

To calculate the Hubble Constant, Prof Riess and others use the "cosmic ladder" approach, which relies on known quantities - so-called "standard candles" - such as the brightness of certain types of supernova to calibrate distances across space.

However, a different approach uses a combination of the afterglow of the Big Bang, known as the Cosmic Microwave Background (CMB), as measured by the Planck spacecraft and a cosmological model known as Lambda-CDM.

http://www.bbc.com/news/science-environment-42630399

How does this relate to what we are doing?
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jwalck

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Message 21624 - Posted: 19 Jan 2018, 15:02:17 UTC

I do not have the answer, but it was an Interesting article! From my understanding of C@H the data we produce could help (and maybe already has helped) with answering questions as these but it would be interesting to hear from someone more knowledgeable in the field.
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Jim1348

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Message 21626 - Posted: 19 Jan 2018, 15:40:46 UTC - in response to Message 21624.  

That is my opinion too. Since Cosmology simulates various alternate universes having various physical properties, it could be relevant to the cited study. But maybe they are looking at entirely different things? I would be interested to know.
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Profile Benjamin Wandelt
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Message 21679 - Posted: 24 Apr 2018, 5:18:55 UTC - in response to Message 21621.  
Last modified: 24 Apr 2018, 5:21:03 UTC

Hi -

This is directly related to what we are doing here - PICO, which we developed using your computations on C@H, is heavily used to derive the Planck/CMB constraints. The recent challenges have been used to validate the results, increasing our confidence in the Planck/CMB results.

As the referenced BBC article describes, there is a tension between the measurement of the expansion speed of nearby objects vs the expansion speed inferred when using the observed patterns in the ancient Cosmic Microwave Background, that reaches us from the furthest observable parts of the universe.
This could mean that the universe changed its expansion speed recently, which would woudl be an exciting discovery.
Unfortunately it is possible that the issue is just that one of the two data sets are wrong; and the results from the recent universe have historically not been as stable as the conclusions drawn from the distant universe. This is perhaps not what you expected, since the nearby universe ought to be easier to study... the problem is that it's more complex and therefore harder to interpret.

At this point we need additional data to arbitrate between the two possibilities of exciting new fundamental physics, and just one of the data sets being interpreted incorrectly.

Watch this space!
Best,
Ben
Creator of Cosmology@Home
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Jim1348

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Message 21680 - Posted: 24 Apr 2018, 11:46:47 UTC - in response to Message 21679.  

Thank you very much. That is just what I wanted to know.
We will crunch on to get the answers.
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