Brad said:
> Where did the 10% number come from?
Consider dropping an object onto the neutron star from infinity. The
amount of gravitational potential energy converted to kinetic energy and
hence thermalised in the impact is
E_g = G M m / r
where M is the mass of the neutron star, r its radius and m the mass of
the object. The object's rest mass energy is
E_m = m c^2
and so the ratio is
E_g G M
--- = -----
E_m r c^2
A solar mass neutron star has a mass of 2x10^30 kg and a radius of about
10^4 m, G is 6x10^-11 m^3 kg^-1 s^-2 and c is 3x10^8 m s^-1, so the
ratio is about 0.1. (All very approximate.)
> And how much does a single marshmallow weigh?
I've no idea. That's why I said "1g of marshmallows".
Rich
VFP Sugar Rush
