Gravitational Wave Flash
Inconveniently timed just before I was due to go to the pub, a new announcement has come out from the LIGO and Virgo gravitational wave detectors. This time it reports a coalescing binary black hole system detected by all three instruments. The new source is called GW170814, which indicates that the signal from it was received by the detectors on the day I returned from Copenhagen this summer!
Here’s the key figure:
The paper is here and there’s a Nature comment piece here.
I have to say that, on its own, the Virgo `detection’ looks rather marginal to me, but assuming that it is a detection this graphic shows how much it helps to localize the source compared to previous signals:
More on this in due course, perhaps, but now I’m off for a pint or two…
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In the Dark 
October 29, 2017 at 10:43 am
The detection of the gravitational waves produced by the merger of two neutron stars –GW170817– has allowed scientists to fix at 70 km/s per megaparsec * the value of the increase in speed of the expansion of the universe in the 130 million light years that separate us from the origin of said merger.
As these calculations approach the speed of light throughout the age of the universe, we can do the inverse calculation to determine the average increase in the velocity of expansion so that the observable universe is of the age stated by the Big Bang Theory.
The result is 300.000 km/s /(13.799/3,26) Mpc =70,820 km/s Mpc. https://molwick.com/en/gravitation/072-gravitational-waves.html#big-bang
October 29, 2017 at 5:45 pm
Er. The age of the Universe is only fixed in the Big Bang theory once the Hubble constant is determined. Your argument, as far as I understand it, is therefore circular.
February 24, 2018 at 11:29 am
That is the idea. Either it is the age of the Universe or the time limit of the observable Universe, but not both!