Recently I met a term "nuclear matter" in some science fiction discussion. It is considered that macroscopic artificial things can be made of such a matter (not of just atoms), like, say, an armor that is very light and but can protect from powerful explosions, smaller-than-atom electronic devices, etc.
I just wonder, is such kind of matter (in stable or long-living form) possible according to known laws of physics? Could such a matter exist at earlier stages of universe evolution? Could it survive until now, and if it could, how can we detect and collect it?
Even more. Is it possible that other life forms consisting of such a matter exist and live, say, somewhere inside stars? Can such things live inside our Sun? Supposing they are smart enough, which way could we communicate with them?
That exists, it is called a neutron star. As it is very instable, it must be kept together by a colossal gravitational force.
In common matter цщкдв, we know such things like a diamond -- the phase, that is stable under high pressure, but is still metastable (and long-living) in normal conditions under low pressure. So, we can make diamond in high-temperature high-pressure conditions, cool it down, and finally, remove pressure. Would such a trick work with a matter taken from neutron star?
The stability is a problem of Pauli's exclusion principle, as they are identical particles. That's why stable nuclei have protons. But then with protons there is the electric repulsion. It is a scale quite different from the one of ordinary matter, since a nucleus is about 100 000 smaller than an atom, and a nucleon is about 2000 heavier than an electron.
In relation to the ultra-light, ultra strong body armour, a SF writer wanting such material needs to postulate something different from "nuclear matter". Atomic matter is largely "empty space" comprising electromagnetic fields and electron wavefunctions. Material that is purely nuclear particles would need to be governed by short range nuclear forces, hence the particle density would be very high. Such material may be ultra strong, but would also be ultra heavy.
Such a SF writer is being lazy, and needs to be more imaginative in creating a novel material.
Alan, nuclear matter artifacts like armor are supposed to be grid-like structures of very strong nuclear matter strings, with grid cell size small enough to block normal matter from getting through.
A quick order of magnitude estimation:
"Nuclear matter strings" with dimensions of 100-200 neutron radius would need 10^15*10^4 neutrons per m.
For a mesh of 1 um dimensions 2x10^6 strings would be needed to make 1m width of "nuclear cloth" at one string thickness.
That's 10^25 neutrons for 1m2 area, which is only 10^-2 kg.
The question then is, how strong would that be?
Assume a binding energy of 10MeV (slightly stronger than in nuclei, but I'm still doing orders of magnitude). A single string will then break if >10^5MeV were supplied instantaneously. That is 10^-8J. Let's take a typical bullet with 1000J energy. That will break 10^11 neutron strands. Remember our 1um mesh has 10^6 strands in a m width, call that 10^4 in the impact zone. So, our nuclear material cloth would need to be at least 10^7 layers just to stop a bullet. Our 1m2 of cloth now becomes 10^5kg, to do something a kevlar vest does (at least, according to the movies).
The "nuclear matter string" would need binding energies orders of magnitude greater than nuclei to be strong enough to make a mesh that would stop a bullet and still be lighter than conventional bullet proof materials,
Unless I've missed something an imaginative SF writer has spotted.
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