R3APER:

@billion57 (View Post)
And the others were discussing a material that is impervious to neutrinos.
(This is reminding me of the immovable object battling the unstoppable force)

Not quite the same though. Neutrinos are particles and if there could ever be such a thing as something that's "truly solid" it WOULD stop neutrinos. Check out Neutron Stars for instance. They are almost completely solid. Unlike atoms and things made of atoms like a "solid" piece of iron (which isn't truly solid at all at the sub-atomic scale) which are almost entirely empty space (yes that's true!), consisting mainly of charged particles held together by the electrostatic force, neutron stars have had electrons from their atoms collide with protons from their atoms during the tremendous force of collapse of the star's core. The electrons striking the protons causes the neutralization of the electric charge, and the 2 particles merge to form a neutron. Thus the entire object that is a Neutron Star consists of a solid (almost) block of neutrons. Neutrons packed together like this are like ball bearings packed as tightly together as they could possible fit. The result is only a small amount of empty space between the neutrons. The brobability that a neutrino would pass entirely through a sheet of this material only 10 neutrons thick without a single collision is VERY unlikely. If you could fill up a coffee cup with this neutron matter, it would weigh as much as all of the buildings put together in New York City (I think where I read it could even weigh as much as a mountain)!

So yeah, this is really dense stuff, and would be great to stop a neutrio. Also it should be the heaviest material TPT, and weigh even more than the current heaviest material. If exposed to high enough pressure it should collapse into SING (that's how blackholes form for real; a star so large that as the material collapses to a neutron start it is so heavy that the particles physically merge together, and thus break space-time itself, as normally 2 separate solid particles can NOT simultaneously occupy the same space, which forms then a singularity, the heart of the phenominon known as a black hole, thus NEUM neutron matter should collapse to SING when NEUM is under pressure greater than 150).