[ExI] Gravitational Waves Detected By LIGO!

spike spike66 at att.net
Fri Feb 12 15:32:07 UTC 2016

-----Original Message-----
From: extropy-chat [mailto:extropy-chat-bounces at lists.extropy.org] On Behalf
Of Giulio Prisco
Sent: Thursday, February 11, 2016 10:30 PM
To: ExI chat list <extropy-chat at lists.extropy.org>
Subject: Re: [ExI] Gravitational Waves Detected By LIGO!

On Thu, Feb 11, 2016 at 9:35 PM, John Clark <johnkclark at gmail.com> wrote:

>>... And the critics were correct, the old
> LIGO wasn't sensitive enough to detect gravitational waves unless you 
> were unrealistically lucky and 2 black holes happened to merge very 
> near to Earth

>...I wouldn't call that "lucky." The astronomers (and the rest of
humanity) would have been killed immediately by a close black hole fusion

Giulio, can you prove that?

It is vaguely coming back to me now, that which I was calculating a quarter
of a century ago.  I was trying to figure out if I could explain gamma ray
bursts by some kind of axial spray of neutrinos from the merging of two
black holes or the merging of a black hole with a neutron star.  Couldn't do

Next I started wondering what does happen with all that spin and energy and
such?  You can do the integration and see that the event horizon changed
significantly, and you can use the old c^2 relationship and figure out an
energy equivalent and so forth.  Thorne kinda explains it in his book.

I don't recall my reasoning at the time, but I do recall that my conclusion
was that if two black holes merged at a distance of the nearest star (about
4 light years) we could scarcely notice here.  If the earth were orbiting
two stars (curcumbinary like Tatooine) and they merged and became a black
hole at that distance, we would survive at first.  The merger itself would
cause a huge GW wave but we would perish from lack of energy.

Oy, those IQ points I used for that have been assigned elsewhere.


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