Re: Two neutron stars on a collision course?

Erik Max Francis wrote:
> Neutron star matter only becomes significantly opaque to neutrinos 
> during "maximum scrunch," the point where the neutron star is formed and

> neutron degeneracy halts its collapse.  But this is only happening 
> during a type II supernova, where you need the mass of the rest of a 
> star to help guide the process -- and where the neutron star formation 
> creates runaway fusion that results in the creation of all those 
> neutrinos in the first place.
> 
> An already-formed neutron star isn't really opaque to neutrinos.

The density at maximum scrunch can't be much greater than that of the 
already-formed neutron star, can it? Also, I've seen the mean free path 
of neutrinos in lead quoted as a light year (1e16 m); if neutronium is 
1e14 times as dense as lead, that would imply a mean free path on the 
order of 100 m, a couple of orders of magnitude smaller than the 
diameter of a neutron star.