Editing 2860: Decay Modes

{{w|radioactive decay|Decay modes}} refer to the different ways in which unstable atomic nuclei transform into more stable ones, typically by emitting particles or radiation. The process of decay is a natural phenomenon that occurs in radioactive substances. There are several types of decay modes, each characterized by the particles emitted or the energy released during the process.

In '''{{w|alpha decay}}''', an unstable nucleus emits an alpha particle, composed of two protons and two neutrons. Alpha decay is the primary source of helium on Earth, as alpha particles are ⁴He nuclei.

In '''{{w|beta decay}}''' (more properly beta-minus decay), a neutron-rich nucleus emits a W⁻ boson, converting one neutron into a proton — as shown in the diagram — which in turn decays into an electron (the titular beta (minus) particle) and an electron antineutrino. The diagram shows only the beta particle, which was the only thing expelled from the nucleus that could be observed directly when the types of nuclear decay were first described and enumerated.

In '''{{w|gamma decay}}''', an unstable nucleus (represented by the lumpy, prolate nucleus in the diagram – representing a high-energy {{w|nuclear isomer}}) emits a high-energy photon known as a gamma-ray and settles into a stabler, lower-energy state.  

In '''{{w|electron capture}}''', a proton-rich atom slurps an electron from the K or L electron shell. This converts a proton into a neutron and emits an electron neutrino. No 'slurp' sound is actually produced in real electron capture event.{{Citation needed}}

In '''{{w|positron emission}}''', or beta plus decay, a proton-rich nucleus emits a W+ boson, converting one proton into a neutron, which in turn decays into a positron, the beta plus particle, and an electron neutrino. Again, the diagram shows only the beta particle, presumably for simplicity. This is much rarer than beta minus decay.

'''Omega decay''': The atom has decayed and left behind a skull in its wake, leaving cracks in the area surrounding it and send neutrons and protons flying everywhere. Whereas ''alpha'', ''beta'', ''gamma'' are the first three letters of the Greek alphabet, ''omega'' is the last, so the name ''omega'' might suggest the ultimate, final decay. The skull presumably represents the finality of such a decay, given that the end stage of human decay leaves behind a skeleton, something that does not exist in nucleons.{{Citation needed}} Many works of science fiction propose forms of radiation and/or particles with further letters in the Greek alphabet, such as {{w|The Omega Directive}} in Star Trek. In real life, the {{w|omega baryon}} was predicted to exist by Murray Gell-Mann's early quark theory, and then discovered several years later with the properties he had predicted. This mode may also represent the atom becoming the origin of a {{w|false vacuum decay}}, a theoretical decay of space itself, which would indeed spread outward and be very final and lethal.

'''Electron wilt''': The electrons surrounding the atom fall to the ground. Some plants are subject to diseases that cause this kind of wilting of their leaves. Electrons will attempt to settle into a 'ground state' but this does not involve them literally slumping to the ground, rather they will be as close as possible to the nucleus subject to the limitations of energy levels and the Pauli exclusion principle. In addition, since the ground is made of atoms,{{citation needed}} the electrons will just keep falling.

'''One big nucleon''': The protons and neutrons combine to form a single huge baryon. {{w|Exotic baryon|Exotic baryons}} with more than the usual three quarks, such as {{w|pentaquarks}}, have been created in the lab but are not known to exist in nature. String theorists propose that black holes are actually {{w|Fuzzball (string theory)|fuzzballs}}, single "subatomic" particles which are macroscopic in size (namely that of their event horizon) formed by the fusion of the strings of in-falling matter under extreme gravitational conditions.

'''Collapse due to invasion by the Sea Peoples''': The atom floats in water, with boats on either side full of Cueballs shooting arrows at it, and the atom is breaking up. The {{w|Sea Peoples}} are a somewhat mysterious group that attacked Egypt and other regions of the eastern Mediterranean in the late Bronze Age (1200-900 BCE). Due to a combination of factors, such as climatic change, mass migration and invasions (including from the Sea Peoples) several nations around the central and eastern Mediterranean underwent societal decline or outright collapse — a period known as the {{w|Late Bronze Age collapse}}. Randall has mentioned the Sea Peoples already in cartoon 1732, "Earth Temperature Timeline".

 

'''Bronze/Iron Age Collapse (Title text)''': Continuing from the last panel of the comic, and making a pun on the Iron Age of civilization with the properties of iron atoms. Nuclear fusion – the merging of small light elements – expels energy, powering stars and and creating increasingly heavier elements which also fuse until the process reaches iron, predominantly ⁵⁶Fe. Fusing iron nucleii does not release energy, so the previous cycle of fusion abruptly stops and the star contracts under gravity (whereupon it can now create the different conditions from which small amounts of heavier nuclei ''do'' form, and disperse to be discovered in later star systems). In contrast, nuclear fission – where atoms spontaneously split into lighter elements, releasing the energy ultimately imbued into them during their synthesis – applies increasingly so to the more heavy nucleii with increasing instabilities as they 'collapse' out into their various fission products. The atomic components of bronze, {{w|tin}} and {{w|copper}}, ''could'' potentially release energy, in the right conditions. Tin's main isotopes (¹¹⁴Sn across to ¹²⁴Sn, with more than two thirds being of weight 116, 118 or 120) are considered stable, as are the two for copper (⁶³Cu and ⁶⁵Cu, being practically all that is naturally present), but trace/synthesised isotopes beyond that range (e.g. actively induced by initiating a neutron bombardment) are known to, eventually, beta(±) decay/'collapse' to forms of antimony (from the tin) or nickel/zinc (from the copper).

[Label:] Radioactive Decay Modes

[A 6x2 table of illustrations depicting types of atomic decay.]

[Label: "alpha decay". An illustration of alpha decay, a small group of 2 protons and 2 neutrons are shown leaving a larger nucleus.]

[Label: "beta decay". An illustration of beta decay, a small particle is shown being ejected from a nucleus while a neutron is shown converting to a proton as indicated by a shaded circle becoming white.]

[Label: "gamma decay". An illustration of gamma decay, a nucleus is shown emitting waves.]

[Label: "electron capture". An illustration of electron capture, a nucleus is shown absorbing one of its electrons along with the text "slurp".]

[Label: "positron emission". An illustration of positron emission, a small particle is shown being ejected from a nucleus while a proton is shown converting to a neutron as indicated by a white circle becoming shaded.]