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Matter is a general term describing any physical substance, which is sometimes defined in incompatible ways in different fields of science. Some definitions are based on historical usage from a time when there was no reason to distinguish mass from simply a quantity of matter.
The process inverse to particle annihilation can be called matter creation; more precisely, we are considering here the process obtained under time reversal of the annihilation process. This process is also known as pair production , and can be described as the conversion of light particles (i.e., photons) into one or more massive particles .
The term comes from an obsolete Middle English philosophical word that Alpher said he found in Webster's dictionary. [5] The word means something along the lines of "primordial substance from which all matter is formed" (that in ancient mythology of many different cultures was called the cosmic egg [6]) and ultimately derives from the hūlē (Ancient Greek: ὕλη), probably through an ...
In regular cold matter, quarks, fundamental particles of nuclear matter, are confined by the strong force into hadrons that consist of 2–4 quarks, such as protons and neutrons. Quark matter or quantum chromodynamical (QCD) matter is a group of phases where the strong force is overcome and quarks are deconfined and free to move.
There are several proposed types of exotic matter: Hypothetical particles and states of matter that have not yet been encountered, but whose properties would be within the realm of mainstream physics if found to exist.
Dark matter is a hypothetical kind of matter that is invisible to the entire electromagnetic spectrum, but which accounts for most of the matter in the universe. The existence and properties of dark matter are inferred from its gravitational effects on visible matter, radiation, and the large-scale structure of the universe.
Scientific terminology is the part of the language that is used by scientists in the context of their professional activities. While studying nature, scientists often encounter or create new material or immaterial objects and concepts and are compelled to name them.
In particle physics and astrophysics, the term 'strange matter' is used in two different contexts, one broader and the other more specific and hypothetical: [1] [2]. In the broader context, our current understanding of the laws of nature predicts that strange matter could be created when nuclear matter (made of protons and neutrons) is compressed beyond a critical density.