Black holes are usually conceived as being the remnant of a massive star that has used up its nuclear fuel, and crushed itself under its own weight. Its gravitational pull at its surface then becomes so great nothing can escape, not even light. It becomes literally a “hole” in the fabric of space-time, and anything that enters can never escape.
In theory, however, a black hole can be of any size, not just very large ones. Any amount of matter, if crushed in upon itself, can theoretically form a black-hole, albeit a very small one if only a small amount of matter is crushed. Some theories suggested that miniature black holes might have been formed in the earliest history of the Universe. Other theories suggest that particle colliders, by crushing two atoms together at tremendous speed, might create a miniature black hole of very tiny dimension. Stephen Hawking in the early 1970s theorized that such miniature black holes were once in great abundance, but later “evaporated” by a quantum tunneling process, so that such miniature black holes no longer exist in our Universe. This process, first theorized by Stephen Hawking, would possibly cause a black hole to evaporate.
If virtual particles are produced in the vicinity of a black hole, it might be possible for one member of the matter-antimatter pair to be pulled into the black hole while the other escapes into space. The particle that would fall into the black hole would negate some of its mass and so the black hole would shrink a little. This would make it look as if the particle that escaped into space had come from the black hole. Hawking radiation would be particularly important in the case of miniature black holes, which might explode in this way. Black holes of very low mass, such as would be created in particle colliders, would have masses of about 10,000,000 atomic mass units [a.m.u., the mass of one proton], and lifetimes of about 1 E-23 seconds, IF Hawking Radiation works as predicted. Hawking Radiation has never been experimentally detected, and exists only in theory.
In theory, a miniature black hole created at rest relative to Earth is considerably different that one created by high-energy cosmic rays striking the Earth. If such high energy cosmic rays were to on occasion create a miniature black hole, as some theories have suggested, it would be traveling at very high speed [0.9999+ c] relative to Earth, and much like a neutrino, simply zip right through Earth in ¼ second without interacting, or if it did interact, it would glom on to a few quarks and barely slow.
Conversely, any miniature black hole created at rest in a collider would essentially be trapped in Earth’s gravitational field, and over seconds to hours, slowly interact and acquire more mass, if Hawking radiation does not work as predicted, or as quickly as predicted, to cause the newly-minted miniature black hole to “evaporate”.
To read more about theoretical miniature black holes, and what the various theories suggests, click here.
Strangelet is the name given to a theoretical form of matter that might exist in nature. Under some theories, a more stable form of nuclear matter might exist, when compared to our normal form of nuclear matter that is formed of up and down quarks combined into protons and neutrons [either two up and one down, or two down and one up], which in turn combine to form the nuclei of atoms.
Under these theories, an equal number of up, down and strange quarks would form a slightly more stable form [slightly less mass], more stable than the Iron nucleus, the most stable form of normal nuclear matter. This is called strange matter, or strange quark matter [sqm]. Unlike normal matter, in which increasing the number of protons and neutrons beyond the 56 present in Iron increases the coulombic repulsion and de-stabilizes the nucleus, no such coulombic repulsion would exist in strange quark matter, and the larger the nucleus, the more stable the sqm nucleus. A very small chunk of sqm is called a strangelet. This sqm could be either slightly positive, or slightly negative, or neutral, under various theories.
Strangelets are also theorized to be creatable in colliders if they collide two large atoms together, such as two lead atoms. In nature, such large atoms do not collide at LHC energies. Instead, high-energy incoming cosmic rays are believed to be single protons, which would likely plow right through a large nucleus sitting on the moon. Also, as is true for miniature black holes, if natural strangelets are neutral they would simply pass through Earth neutrino-like at high speed if created by cosmic rays. If created instead at rest relative to Earth in a collider, they would be trapped by Earth’s gravitational field, and potentially be able to interact with normal matter, acquire quarks, and grow larger.
Cosmologists have theorized that so-called “neutron stars” can form from collapsed stars in which the electrons and protons of a massive collapsed star, not quite large enough to form a black hole, combine together to from neutrons, so the entire star becomes a massive single nucleus of nothing but neutrons. Most theories about such neutron stars now show that they would more likely form into sqm, and they are now called “strange stars” instead of “neutron stars”.
Searches for sqm in nature,...fruitless. For more information click here.