[ExI] LIGO: RE: Hey, look on the bright side

[John Clark]

On Thu, Nov 10, 2016 at 11:28 PM, spike <spike66 at att.net> wrote:

>
> ​> ​
> Imagine a neutron star of less than Chandrasekhar’s limit, but big. I
> think two solar masses works for this thought experiment.  Now imagine you
> are a photon and you originate very nearby, perhaps from a neutron decay or
> something.  You head outbound, you get way red-shifted, but go on your
> way.  Now imagine two such neutron stars orbiting each other at some
> distance.  If you originate between the two and head outbound along an axis
> perpendicular to the line connecting the two (like the axle on your bike
> tire with the two neutron stars on the rim) then you still get away, but
> even more red shift.
> ​ ​
> OK now imagine bringing the two neutron stars closer together until
> eventually an event horizon envelopes the both of them.
> ​ [...]
> Afterwards the neutron stars move apart toward aphelion


​Once ​the two Neutron stars get close enough to form a event horizon
they're not getting out again and neither is that photon. A Black Hole will
have been formed

​with a non spherical ​horizon which will then vibrate violently and shed
gravitational waves and become spherical in the process. That will take a
second or two.

Chandrasekhar’s limit is 1.44 solar masses
​
for a non rotating dead star that has run out of internal energy, like
fusion, to push things out and fight against gravity. A neutron star can be
more massive than what Chandrasekhar
​
says if it is rotating fast enough.
​
Theory can't yet pinpoint how massive neutron stars can be because we
aren't sure exactly how strong Neutronium
​
(the stuff neutron stars are made of) is, and if the star spins too fast it
will fly apart,  but we know approximately. The limit is somewhere between
2 and 3.5 solar masses. Any more massive than that and that the neutron
star turns into a Black Hole. And theory matches pretty well with
observation. The most massive neutron star ever observed  is 1.97
​ solar
 masses and is spinning at 317 revolutions per second. The least massive
Black Hole ever found is 3.8 solar masses.

John K Clark
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.extropy.org/pipermail/extropy-chat/attachments/20161111/095b7f77/attachment.html>