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9

An opaque medium is a medium which is not transparent. Typically, the term refers to electromagnetic radiation, but in principle it may refer to any entity, also neutrinos. A medium can be opaque to one kind of particles, but transparent to another. For instance, Earth's atmosphere is largely opaque to UV radiation, but transparent to visible light. Optical ...


1

It's "in principle" possible. For example if we had a black hole the size of a small mountain on Earth (this kind of black hole are possible in theory but cannot form from stellar collapse) then it'd be impossible to confine in a laboratory, and it would fall through the Earth to eventually settle at the Earth's core. We could then argue that the ...


2

That would be a bigger black hole. Black holes are indestructible but a big one can consume a smaller one. The collision between anything and a black hole results in a black hole plus some optional debris from whatever the other thing is, so the result of a collision between two black holes is simply a bigger black hole.


11

You say you're a mathematician, so let's put this in terms of math. Let's say you have a source of neutrinos with an initial intensity $I_0$, in units of $\text{neutrinos/sec/m}^2$, (that is, the number of neutrinos passing through a surface area per second. This beam of neutrinos is passing through a dense medium of density $\rho$, in units of $\text{kg/m}^...


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Opaque in this context means the same thing as it would optically, for light. The neutrinos do not pass through and are either scattered or absorbed due to the density of the matter in the star.


1

tl;dr Size plays a role in this very specific scenario in kind of an indirect way, but generally speaking, variability in its enormous scope depends on a lot of other things more for other kinds of objects, and this is not a relation to be applied outside of maybe pulsars (probably) Let me know if some of these assumptions I’m making here are wrong, but I’m ...


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