Strange matter

Strange matter is an ultra-dense phase of matter that is theorized to form inside particularly massive neutron stars. It is theorized that when the neutronium which makes up a neutron star is put under sufficient pressure due to the star's gravity, the individual neutrons break down and their constituent quarks form strange matter. The star then becomes known as a "strange star" or "quark star".

Strange matter is composed of strange quarks bound to each other directly, in a similar manner to how neutronium is composed of neutrons; a strange star is essentially a single gigantic nucleon. (Normal matter is composed of "up" and "down" quarks only.) A strange star lies between neutron stars and black holes in terms of both mass and density, and if sufficient additional matter is added to a strange star it will collapse into a black hole as well.

Strange matter, unlike neutronium, may be stable outside of the intense pressure that produced it; small substellar pieces of strange stars (sometimes called strangelets) may exist in space in a wide range of sizes all the way down to atomic scales. There is some concern that ordinary matter, upon contacting a strangelet, would be compressed into additional strange matter by its gravity; strangelets would therefore be able to "eat" any ordinary matter they came into contact with, such as planets or stars; worlds going through such a process are known as degenerate worlds. This is a very rare occurance, however.

Strangelets are thought to have a net positive charge, which is neutralized by the presence of degenerate electrons extending slightly beyond the edge of the strangelet, a kind of electron "atmosphere." If a normal matter atomic nucleus encounters a strangelet, it will approach until it begins penetrating this negatively charged atmosphere. At that point it will start to see the positive electrical potential and be repelled from the strangelet. Sufficiently energetic nuclei, or neutrons (which are unaffected by electrical charges), can reach the strangelet and be absorbed; the up/down/strange quark ratio would then readjust by beta decay.