Date: 17/02/2019 10:02:09
From: Tau.Neutrino
ID: 1347507
Subject: Gravitational waves will settle cosmic conundrum

Gravitational waves will settle cosmic conundrum

Measurements of gravitational waves from approximately 50 binary neutron stars over the next decade will definitively resolve an intense debate about how quickly our universe is expanding, according to new findings.

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Date: 17/02/2019 10:14:35
From: mollwollfumble
ID: 1347512
Subject: re: Gravitational waves will settle cosmic conundrum

Tau.Neutrino said:


Gravitational waves will settle cosmic conundrum

Measurements of gravitational waves from approximately 50 binary neutron stars over the next decade will definitively resolve an intense debate about how quickly our universe is expanding, according to new findings.

more…

Um, what. How would that help? I doubt if measurement accuracy would suffice.

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Date: 17/02/2019 10:53:52
From: mollwollfumble
ID: 1347539
Subject: re: Gravitational waves will settle cosmic conundrum

mollwollfumble said:


Tau.Neutrino said:

Gravitational waves will settle cosmic conundrum

Measurements of gravitational waves from approximately 50 binary neutron stars over the next decade will definitively resolve an intense debate about how quickly our universe is expanding, according to new findings.

more…

Um, what. How would that help? I doubt if measurement accuracy would suffice.

> Binary neutron star events are rare, but they are invaluable in providing another route to track how the universe is expanding. The gravitational waves they emit cause ripples in space-time that can be detected by the Laser Interferometer Gravitational-Wave Observatory (LIGO) and the Virgo experiments, giving a precise measurement of the system’s distance from Earth. By additionally detecting the light from the accompanying explosion, astronomers can determine the system’s velocity, and hence calculate the Hubble constant using Hubble’s law.

I think I need to read the research paper. I don’t immediately see how either of those is possible.

https://arxiv.org/pdf/1802.03404.pdf
“Prospects for resolving the Hubble constant tension with standard sirens”

The first half of the article is not relevant, it’s merely an evaluation of the discrepancy in the Hubble constant between Planck CMBR measurements and Cepheid measurements.

This is what I mean about accuracy. This is a figure from the paper. Each coloured line represents the Hubble constant calculated from a single neutron star merger (simulated data). The dotted vertical line is the real Hubble constant. This is not a particularly accurate way of calculating the Hubble constant.

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