<div dir="ltr"><div dir="ltr"><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div></div><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Mon, Aug 19, 2019 at 7:13 PM <<a href="mailto:spike@rainier66.com">spike@rainier66.com</a>> wrote:<br></div><div dir="ltr" class="gmail_attr"><br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><i><span class="gmail_default" style="font-family:arial,helvetica,sans-serif">></span>I don't expect the mailing list will go down henceforth, for Max has asked<br>me to take over the cheerful task of seeing to it that it stays up.  This<br>honor and privilege is one I embraced after mulling it over for several<br>milliseconds.</i></blockquote><div><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><font size="4">Thanks Spike, you're a gentleman and a scholar! </font></div><div dir="ltr" class="gmail_attr"><br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div lang="EN-US"><div class="gmail-m_-8416854151880281136WordSection1"><p class="MsoNormal"><i><u></u></i></p><div><div><p class="MsoNormal"><i>John I hope you will post the marvelous news you and I learned a few days ago from LIGO please.</i></p></div></div></div></div></blockquote><div><br></div><div><font size="4" style="font-family:arial,helvetica,sans-serif"><span class="gmail_default" style="font-family:arial,helvetica,sans-serif">Be happy to. On</span> August 14 2019 LIGO detected for the first time Gravitational Waves coming from a Black Hole-Neutron Star merger; it was <span class="gmail_default" style="font-family:arial,helvetica,sans-serif">870</span> million light years away. They detected something like this a few months ago but were only 13% confident it was real, this time the signal was much stronger and they're 99% confident. They've narrowed the source down to a square 23 degrees on a side, so far they haven't detected any electromagnetic waves from it but have just started looking. </font></div><div><font size="4" style="font-family:arial,helvetica,sans-serif"><br></font></div><div><font size="4" style="font-family:arial,helvetica,sans-serif">This type of merger produces a cleaner signal that is easier to analyze than when two Black Holes merge <span class="gmail_default" style="font-family:arial,helvetica,sans-serif">because if </span></font><span style="font-size:large">a big thing and a small thing merge you could make certain approximations that wouldn't work if the two things were of equal size<span class="gmail_default" style="font-family:arial,helvetica,sans-serif">.</span> <span class="gmail_default" style="font-family:arial,helvetica,sans-serif"></span></span><span class="gmail_default" style="font-size:large;font-family:arial,helvetica,sans-serif">A</span><span style="font-size:large">nd if the Black Hole was large enough the tidal forces wouldn't be strong enough to break up a Neutron Star until after it passed through the Event Horizon so the material dynamics of the star would have no effect on the signal that we see. <span class="gmail_default" style="font-family:arial,helvetica,sans-serif">S</span></span><span style="font-size:large"><span class="gmail_default" style="font-family:arial,helvetica,sans-serif">o you</span></span><span style="font-family:arial,helvetica,sans-serif;font-size:large"> can <span class="gmail_default">make</span> a more rigorous test of General Relativity, </span><span style="font-family:arial,helvetica,sans-serif;font-size:large">and if you could spot a few dozen of these sort of mergers it could give us the best value yet of the Hubble constant which has been in dispute lately and perhaps tell us if we're heading for the Big Rip or not</span></div><div><br></div><div><span style="font-size:large">If the Black Hole was smaller then the Neutron Star would break up on our side of the Event Horizon making the signal more complex, but <span class="gmail_default" style="font-family:arial,helvetica,sans-serif">on the other hand </span>that would give us information about the nature of Neutronium and</span><span class="gmail_default" style="font-size:large;font-family:arial,helvetica,sans-serif">,</span><span style="font-size:large"> other than  glitches with Pulsars caused by starquakes</span><span class="gmail_default" style="font-size:large;font-family:arial,helvetica,sans-serif">, it</span><span style="font-size:large"> is the </span><span class="gmail_default" style="font-size:large;font-family:arial,helvetica,sans-serif">only </span><span style="font-size:large">way we </span><span class="gmail_default" style="font-size:large;font-family:arial,helvetica,sans-serif">h</span><span style="font-size:large">ave to compare theory with reality because </span><span class="gmail_default" style="font-size:large;font-family:arial,helvetica,sans-serif">we can't make</span><span style="font-size:large"> Neutronium in a lab</span><span class="gmail_default" style="font-size:large;font-family:arial,helvetica,sans-serif">.</span></div><div><span class="gmail_default" style="font-size:large;font-family:arial,helvetica,sans-serif"><br></span></div><div><span class="gmail_default" style="font-size:large;font-family:arial,helvetica,sans-serif"><a href="https://www.scientificamerican.com/article/astronomers-spy-a-black-hole-devouring-a-neutron-star/">Astronomers Spy a Black Hole Devouring a Neutron Star</a><br></span></div><div><span class="gmail_default" style="font-size:large;font-family:arial,helvetica,sans-serif"><br></span></div><div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><font size="4">John K Clark</font></div><br></div><div><br></div></div></div>