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The Cosmic Conundrum


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#1 hazelm

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Posted 16 February 2019 - 07:10 AM

https://www.scienced...p Science News)

 

Measuring the gravitational waves of neutron star collisions will reveal how fast our universe is expanding.  By getting a more accurate measurement of the Hubble Constant, they feel sure they can get a more accurate measurement of the expansion.   "definitely"

 

 

(my comment) If it doesn't collapse first, a la E. A. Poe.   ----- I had to add that. :-)   -----



#2 OceanBreeze

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Posted 16 February 2019 - 03:46 PM

Cepheid stars and supernovae give a value of 72. The CMB gives a value of 67. Let’s say the binaries will give a value of 69. Will having a third value settle anything or just add to the confusion? I wonder.

 



#3 OceanBreeze

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Posted 16 February 2019 - 04:16 PM

I don't see the problems you mentioned. Yes, the GW and light travel at c. But they each provide different information.

The GW amplitude "loudness" gives information on the distance to the binary collision, while the light (actually the redshift) provides

information on the velocity. Those two things tell us about the expansion rate at that point in space.

 

The problem is, this method is not very reliable as the GW that is received may be from different places in the disturbance, throwing off the distance measurement. So they need to do a lot of readings and average them.

 

Right now, we have two different measurements from the CMB and from the Cepheids and they do not agree. So this will either provide a third reading, and more confusion,  or it may confirm one of the other two and settle the question.

 

I would just average the two readings we have and save a lot of time and money.