Post by aijutsuSuppose you shone a flashlight upon a ball of neutronium. What colour
would it be?
The more I thought about it, the more I realized I didn't know.
Optical wavelength photons interact with electrons of atoms. The
neutrons in neutronium, would they do anything with the photons?
Would optical wavelength photons simply pass through (that is,
neutronium is transparent)?
"Neutronium" isn't used as a scientific term, but as matter consisting
entirely of neutrons, you could mean one (or more) of 3 possibilities:
1) The stuff of neutron stars: Matter held together by gravity so strong
that electrons and protons are essentially crushed out of existence to
become neutrons. In reality there are still some electrons and protons
(enough electrons so that all the energy states lower than that required
to form a neutron from e+p are occupied) plus possible strange matter and
so forth. Real neutron stars are likely extremely hot even though they
are so dim as stars go since they are so small in diameter, so they'd
probably exhibit extremely hot black body radiation. Since they have
charged particles to emit electromagnetic radiation as a black body,
they'd appear blue-white. Don't get too close since in addition to the
gravity effects, blackbody radiation at such temps would emit loads of UV
and X-rays.
2) "Neutronium" of Star Trek. Neutrons packed extremely densely but
at normal temperatures and pressures. Being the stuff of science fiction
it could be any color the author wants, but as a best guess, with no
electrons to interfere with light, probably perfectly clear would be
best.
3) Real life neutrons at normal temperature and pressure. What
scientists call "thermal neutrons". Since the neutrons are all
independent of each other the best description might be a _gas_, but this
is no ordinary gas. Since neutrons won't interact with the electrons of
matter, this "gas" occupies the same space as other matter. Neutrons
only interact with the nuclei, and could scatter from them (kind of like
atoms of ordinary matter interact with each other if they don't react)
or undergo nuclear reactions such as fissioning uranium or other
transmutation. I'm not sure if such a thing as a "bottle" that could
"contain" some neutron gas could exist. What is the best neutron
reflector, and could a "bottle" of this substance confine neutrons
within an otherwise empty interior (until they decay, of course)?
Anyway, the neutrons shouldn't affect light at all.