248 relations: Accretion (astrophysics), Actinides in the environment, Activation energy, Age of the universe, Alpha decay, Alpha particle, Amount of substance, Annual Reviews (publisher), Antimatter, Aplastic anemia, Arithmetic mean, Atmosphere, Atomic nucleus, Atomic number, Atomic orbital, Auger effect, Avalanche, Avogadro constant, Background radiation, Barium, Becquerel, Beryllium, Beta decay, Beta particle, Big Bang, Big Bang nucleosynthesis, Bismuth, Boron, Canadian Journal of Physics, Carbon, Carbon-14, Cathode ray, Cathode ray tube, Chaos theory, Characteristic X-ray, Chemical bond, Chemical element, Chemische Berichte, Chernobyl disaster, Cluster decay, Conservation of energy, Conservation of mass, Copper-64, Cosmic ray, Cosmogenic nuclide, Coulomb's law, Crimes involving radioactive substances, Crust (geology), Curie, Darmstadt, ..., Decay chain, Decay correction, Demos Medical Publishing, Deuterium, Differential calculus, Differential equation, Double beta decay, Double electron capture, E (mathematical constant), Earth, Earth's internal heat budget, Eigenvalues and eigenvectors, Electric field, Electromagnetic field, Electromagnetic radiation, Electromagnetism, Electron, Electron capture, Electron neutrino, Elihu Thomson, Emission spectrum, Encyclopædia Britannica Eleventh Edition, Encyclopædia Britannica Online, Enema, Enrico Fermi, Entropy, Ernest Rutherford, European Union, European units of measurement directives, Excited state, Exponential decay, Extinct radionuclide, Fallout shelter, France, Frederick Soddy, Friction, Function (mathematics), Gamma ray, Geiger counter, Germany, Glenn T. Seaborg, Gray (unit), Ground state, GSI anomaly, GSI Helmholtz Centre for Heavy Ion Research, Half-life, Hardware random number generator, Helium, Henri Becquerel, Hermann Joseph Muller, Highly charged ion, Hydrogen, Induced radioactivity, Integrating factor, Internal conversion, International Commission on Radiological Protection, International System of Units, Invariant mass, Ion, Ionizing radiation, Isotope, Isotopes of argon, Isotopes of beryllium, Isotopes of bismuth, Isotopes of calcium, Isotopes of hydrogen, Isotopes of lead, Isotopes of manganese, Isotopes of nitrogen, Isotopes of polonium, Isotopes of protactinium, Isotopes of radium, Isotopes of radon, Isotopes of rhenium, Isotopes of silicon, Isotopes of tellurium, Isotopes of thallium, Isotopes of thorium, Isotopic labeling, Isotropy, Lambda, Leo Szilard, List of nuclides, Lists of nuclear disasters and radioactive incidents, Lithium, Lulu.com, Macroscopic scale, Magnetic field, Mantle (geology), Marie Curie, Mass, Mass in special relativity, Mass number, Modulation, Mole (unit), Momentum, Multiplicative calculus, National Council on Radiation Protection and Measurements, National Physical Laboratory (United Kingdom), Natural nuclear fission reactor, Natural number, Nebula, Neon lamp, Neutrino, Neutron, Neutron emission, Nikola Tesla, Nobel Prize in Physiology or Medicine, Nuclear engineering, Nuclear fission, Nuclear force, Nuclear isomer, Nuclear medicine, Nuclear pharmacy, Nuclear physics, Nuclear power, Nuclear reaction, Nuclear reactor, Nuclear transmutation, Nucleon, Nucleosynthesis, Orders of magnitude (time), Organism, Oscillation, Particle accelerator, Particle decay, Particle number, Patent medicine, Paul Ulrich Villard, Phosphorescence, Photon, Pierre Curie, Poisson distribution, Poisson point process, Polonium, Positron, Positron emission, Potassium-40, Primordial nuclide, Proton, Proton emission, Quantum fluctuation, Quantum mechanics, Quantum state, Quantum tunnelling, Radiation, Radiation therapy, Radioactive contamination, Radioactive decay, Radioactive displacement law of Fajans and Soddy, Radioactive quackery, Radioactivity in the life sciences, Radiogenic nuclide, Radiometric dating, Radionuclide, Radium, Radon, Randomness, Rest frame, Rhenium, Rock (geology), Rolf Maximilian Sievert, Salt (chemistry), Second law of thermodynamics, Secular equilibrium, Sievert, Solar flare, Solar System, Spin (physics), Spontaneous emission, Spontaneous fission, Springer Publishing, Stable isotope ratio, Stable nuclide, Star, Statistical mechanics, Stochastic, Storage ring, Supernova, Supernova nucleosynthesis, Synthetic element, Tau, Tellurium, Thermal equilibrium, Thorium, Time constant, Transient equilibrium, Tritium, Unicode, Uranium, Uranium-234, Vanderbilt University, Weak interaction, Wilhelm Röntgen, William Herbert Rollins, World War II, Wu experiment, X-ray. Expand index (198 more) » « Shrink index
In astrophysics, accretion is the accumulation of particles into a massive object by gravitationally attracting more matter, typically gaseous matter, in an accretion disk.
Actinides in the environment refer to the sources, environmental behaviour and effects of actinides in Earth's environment.
In chemistry and physics, activation energy is the energy which must be available to a chemical or nuclear system with potential reactants to result in: a chemical reaction, nuclear reaction, or other various other physical phenomena.
In physical cosmology, the age of the universe is the time elapsed since the Big Bang.
Alpha decay or α-decay is a type of radioactive decay in which an atomic nucleus emits an alpha particle (helium nucleus) and thereby transforms or 'decays' into an atom with a mass number that is reduced by four and an atomic number that is reduced by two.
Alpha particles consist of two protons and two neutrons bound together into a particle identical to a helium-4 nucleus.
Amount of substance (symbol for the quantity is 'n') is a standard-defined quantity that measures the size of an ensemble of elementary entities, such as atoms, molecules, electrons, and other particles.
Annual Reviews, located in Palo Alto California, Annual Reviews is a nonprofit publisher dedicated to synthesizing and integrating knowledge for the progress of science and the benefit of society.
In modern physics, antimatter is defined as a material composed of the antiparticle (or "partners") to the corresponding particles of ordinary matter.
Aplastic anaemia is a rare disease in which the bone marrow and the hematopoietic stem cells that reside there are damaged.
In mathematics and statistics, the arithmetic mean (stress on third syllable of "arithmetic"), or simply the mean or average when the context is clear, is the sum of a collection of numbers divided by the number of numbers in the collection.
An atmosphere is a layer or a set of layers of gases surrounding a planet or other material body, that is held in place by the gravity of that body.
The atomic nucleus is the small, dense region consisting of protons and neutrons at the center of an atom, discovered in 1911 by Ernest Rutherford based on the 1909 Geiger–Marsden gold foil experiment.
The atomic number or proton number (symbol Z) of a chemical element is the number of protons found in the nucleus of an atom.
In quantum mechanics, an atomic orbital is a mathematical function that describes the wave-like behavior of either one electron or a pair of electrons in an atom.
The Auger effect is a physical phenomenon in which the filling of an inner-shell vacancy of an atom is accompanied by the emission of an electron from the same atom.
An avalanche (also called a snowslide) is a cohesive slab of snow lying upon a weaker layer of snow in the snowpack that fractures and slides down a steep slope when triggered.
In chemistry and physics, the Avogadro constant (named after scientist Amedeo Avogadro) is the number of constituent particles, usually atoms or molecules, that are contained in the amount of substance given by one mole.
Background radiation is a measure of the ionizing radiation present in the environment at a particular location which is not due to deliberate introduction of radiation sources.
Barium is a chemical element with symbol Ba and atomic number 56.
The becquerel (symbol: Bq) is the SI derived unit of radioactivity.
Beryllium is a chemical element with symbol Be and atomic number 4.
In nuclear physics, beta decay (β-decay) is a type of radioactive decay in which a beta ray (fast energetic electron or positron) and a neutrino are emitted from an atomic nucleus.
A beta particle, also called beta ray or beta radiation, (symbol β) is a high-energy, high-speed electron or positron emitted by the radioactive decay of an atomic nucleus during the process of beta decay.
The Big Bang theory is the prevailing cosmological model for the universe from the earliest known periods through its subsequent large-scale evolution.
In physical cosmology, Big Bang nucleosynthesis (abbreviated BBN, also known as primordial nucleosynthesis, arch(a)eonucleosynthesis, archonucleosynthesis, protonucleosynthesis and pal(a)eonucleosynthesis) refers to the production of nuclei other than those of the lightest isotope of hydrogen (hydrogen-1, 1H, having a single proton as a nucleus) during the early phases of the Universe.
Bismuth is a chemical element with symbol Bi and atomic number 83.
Boron is a chemical element with symbol B and atomic number 5.
The Canadian Journal of Physics is a peer-reviewed scientific journal covering a broad range of physics.
Carbon (from carbo "coal") is a chemical element with symbol C and atomic number 6.
Carbon-14, 14C, or radiocarbon, is a radioactive isotope of carbon with an atomic nucleus containing 6 protons and 8 neutrons.
Cathode rays (also called an electron beam or e-beam) are streams of electrons observed in vacuum tubes.
The cathode ray tube (CRT) is a vacuum tube that contains one or more electron guns and a phosphorescent screen, and is used to display images.
Chaos theory is a branch of mathematics focusing on the behavior of dynamical systems that are highly sensitive to initial conditions.
Characteristic X-rays are emitted when outer-shell electrons fill a vacancy in the inner shell of an atom, releasing X-rays in a pattern that is "characteristic" to each element.
A chemical bond is a lasting attraction between atoms, ions or molecules that enables the formation of chemical compounds.
A chemical element is a species of atoms having the same number of protons in their atomic nuclei (that is, the same atomic number, or Z).
Chemische Berichte (usually abbreviated as Ber. or Chem. Ber.) was a German-language scientific journal of all disciplines of chemistry founded in 1868.
The Chernobyl disaster, also referred to as the Chernobyl accident, was a catastrophic nuclear accident.
Cluster decay, also named heavy particle radioactivity or heavy ion radioactivity, is a type of nuclear decay in which an atomic nucleus emits a small "cluster" of neutrons and protons, more than in an alpha particle, but less than a typical binary fission fragment.
In physics, the law of conservation of energy states that the total energy of an isolated system remains constant, it is said to be ''conserved'' over time.
The law of conservation of mass or principle of mass conservation states that for any system closed to all transfers of matter and energy, the mass of the system must remain constant over time, as system's mass cannot change, so quantity cannot be added nor removed.
Copper-64 is a positron emitting isotope of copper, with applications for molecular radiotherapy and positron emission tomography.
Cosmic rays are high-energy radiation, mainly originating outside the Solar System and even from distant galaxies.
Cosmogenic nuclides (or cosmogenic isotopes) are rare nuclides (isotopes) created when a high-energy cosmic ray interacts with the nucleus of an in situ Solar System atom, causing nucleons (protons and neutrons) to be expelled from the atom (see cosmic ray spallation).
Coulomb's law, or Coulomb's inverse-square law, is a law of physics for quantifying the amount of force with which stationary electrically charged particles repel or attract each other.
This is a list of criminal (or arguably, allegedly, or potentially criminal) acts intentionally involving radioactive substances.
In geology, the crust is the outermost solid shell of a rocky planet, dwarf planet, or natural satellite.
The curie (symbol Ci) is a non-SI unit of radioactivity originally defined in 1910.
Darmstadt is a city in the state of Hesse in Germany, located in the southern part of the Rhine-Main-Area (Frankfurt Metropolitan Region).
In nuclear science, the decay chain refers to a series of radioactive decays of different radioactive decay products as a sequential series of transformations.
Decay correction is a method of estimating the amount of radioactive decay at some set time before it was actually measured.
Demos Medical Publishing, now an imprint of Springer Publishing Company, publishes books on neurology, oncology, pathology, and other medical subjects.
Deuterium (or hydrogen-2, symbol or, also known as heavy hydrogen) is one of two stable isotopes of hydrogen (the other being protium, or hydrogen-1).
In mathematics, differential calculus is a subfield of calculus concerned with the study of the rates at which quantities change.
A differential equation is a mathematical equation that relates some function with its derivatives.
In nuclear physics, double beta decay is a type of radioactive decay in which two protons are simultaneously transformed into two neutrons, or vice versa, inside an atomic nucleus.
Double electron capture is a decay mode of atomic nucleus.
The number is a mathematical constant, approximately equal to 2.71828, which appears in many different settings throughout mathematics.
Earth is the third planet from the Sun and the only astronomical object known to harbor life.
Earth's internal heat budget is fundamental to the thermal history of the Earth.
In linear algebra, an eigenvector or characteristic vector of a linear transformation is a non-zero vector that changes by only a scalar factor when that linear transformation is applied to it.
An electric field is a vector field surrounding an electric charge that exerts force on other charges, attracting or repelling them.
An electromagnetic field (also EMF or EM field) is a physical field produced by electrically charged objects.
In physics, electromagnetic radiation (EM radiation or EMR) refers to the waves (or their quanta, photons) of the electromagnetic field, propagating (radiating) through space-time, carrying electromagnetic radiant energy.
Electromagnetism is a branch of physics involving the study of the electromagnetic force, a type of physical interaction that occurs between electrically charged particles.
The electron is a subatomic particle, symbol or, whose electric charge is negative one elementary charge.
Electron capture (K-electron capture, also K-capture, or L-electron capture, L-capture) is a process in which the proton-rich nucleus of an electrically neutral atom absorbs an inner atomic electron, usually from the K or L electron shell.
The electron neutrino is a subatomic lepton elementary particle which has no net electric charge.
Elihu Thomson (March 29, 1853 – March 13, 1937) was an English-born American engineer and inventor who was instrumental in the founding of major electrical companies in the United States, the United Kingdom and France.
The emission spectrum of a chemical element or chemical compound is the spectrum of frequencies of electromagnetic radiation emitted due to an atom or molecule making a transition from a high energy state to a lower energy state.
The Encyclopædia Britannica Eleventh Edition (1910–11) is a 29-volume reference work, an edition of the Encyclopædia Britannica.
Encyclopædia Britannica Online is the website of Encyclopædia Britannica, Inc. and its Encyclopædia Britannica, with more than 120,000 articles that are updated regularly.
An enema is the injection of fluid into the lower bowel by way of the rectum.
Enrico Fermi (29 September 1901 – 28 November 1954) was an Italian-American physicist and the creator of the world's first nuclear reactor, the Chicago Pile-1.
In statistical mechanics, entropy is an extensive property of a thermodynamic system.
Ernest Rutherford, 1st Baron Rutherford of Nelson, HFRSE LLD (30 August 1871 – 19 October 1937) was a New Zealand-born British physicist who came to be known as the father of nuclear physics.
The European Union (EU) is a political and economic union of EUnum member states that are located primarily in Europe.
As of 2009, the European Union had issued two units of measurement directives: In 1971 it issued Directive 71/354/EEC which required EU member states to standardise on the International System of Units (SI) rather than use a variety of CGS and MKS units then in use.
In quantum mechanics, an excited state of a system (such as an atom, molecule or nucleus) is any quantum state of the system that has a higher energy than the ground state (that is, more energy than the absolute minimum).
A quantity is subject to exponential decay if it decreases at a rate proportional to its current value.
An extinct radionuclide is a radionuclide that was formed by nucleosynthesis before the formation of the Solar System, about 4.6 billion years ago, and incorporated into it, but has since decayed to virtually zero abundance, due to having a half-life shorter than about 100 million years.
A fallout shelter is an enclosed space specially designed to protect occupants from radioactive debris or fallout resulting from a nuclear explosion.
France, officially the French Republic (République française), is a sovereign state whose territory consists of metropolitan France in Western Europe, as well as several overseas regions and territories.
Frederick Soddy FRS (2 September 1877 – 22 September 1956) was an English radiochemist who explained, with Ernest Rutherford, that radioactivity is due to the transmutation of elements, now known to involve nuclear reactions.
Friction is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other.
In mathematics, a function was originally the idealization of how a varying quantity depends on another quantity.
A gamma ray or gamma radiation (symbol γ or \gamma), is penetrating electromagnetic radiation arising from the radioactive decay of atomic nuclei.
The Geiger counter is an instrument used for detecting and measuring ionizing radiation used widely in applications such as radiation dosimetry, radiological protection, experimental physics and the nuclear industry.
Germany (Deutschland), officially the Federal Republic of Germany (Bundesrepublik Deutschland), is a sovereign state in central-western Europe.
Glenn Theodore Seaborg (April 19, 1912February 25, 1999) was an American chemist whose involvement in the synthesis, discovery and investigation of ten transuranium elements earned him a share of the 1951 Nobel Prize in Chemistry.
The gray (symbol: Gy) is a derived unit of ionizing radiation dose in the International System of Units (SI).
The ground state of a quantum mechanical system is its lowest-energy state; the energy of the ground state is known as the zero-point energy of the system.
One of the experimental facilities at the German laboratory GSI Helmholtz Centre for Heavy Ion Research in Darmstadt is an ''E''xperimental ''S''torage ''R''ing (ESR) with electron cooling in which large numbers of highly charged radioactive ions can be stored for extended periods of time.
The GSI Helmholtz Centre for Heavy Ion Research (GSI Helmholtzzentrum für Schwerionenforschung) is a federally and state co-funded heavy ion research center in the Wixhausen suburb of Darmstadt, Germany.
Half-life (symbol t1⁄2) is the time required for a quantity to reduce to half its initial value.
In computing, a hardware random number generator (true random number generator, TRNG) is a device that generates random numbers from a physical process, rather than a computer program.
Helium (from lit) is a chemical element with symbol He and atomic number 2.
Antoine Henri Becquerel (15 December 1852 – 25 August 1908) was a French physicist, Nobel laureate, and the first person to discover evidence of radioactivity.
Hermann Joseph Muller (December 21, 1890 – April 5, 1967) was an American geneticist, educator, and Nobel laureate best known for his work on the physiological and genetic effects of radiation (mutagenesis) as well as his outspoken political beliefs.
Highly charged ions (HCI) are ions in very high charge states due to the loss of many or most of their bound electrons by energetic collisions or high-energy photon absorption.
Hydrogen is a chemical element with symbol H and atomic number 1.
Induced radioactivity occurs when a previously stable material has been made radioactive by exposure to specific radiation.
In mathematics, an integrating factor is a function that is chosen to facilitate the solving of a given equation involving differentials.
Internal conversion is a radioactive decay process wherein an excited nucleus interacts electromagnetically with one of the orbital electrons of the atom.
The International Commission on Radiological Protection (ICRP) is an independent, international, non-governmental organization, with the mission to provide recommendations and guidance on radiation protection.
The International System of Units (SI, abbreviated from the French Système international (d'unités)) is the modern form of the metric system, and is the most widely used system of measurement.
The invariant mass, rest mass, intrinsic mass, proper mass, or in the case of bound systems simply mass, is the portion of the total mass of an object or system of objects that is independent of the overall motion of the system.
An ion is an atom or molecule that has a non-zero net electrical charge (its total number of electrons is not equal to its total number of protons).
Ionizing radiation (ionising radiation) is radiation that carries enough energy to liberate electrons from atoms or molecules, thereby ionizing them.
Isotopes are variants of a particular chemical element which differ in neutron number.
Argon (18Ar) has 24 known isotopes, from 30Ar to 53Ar and 1 isomer (32mAr), three of which are stable, 36Ar, 38Ar, and 40Ar.
Beryllium (4Be) has 12 known isotopes, but only one of these isotopes is stable and a primordial nuclide.
Bismuth (83Bi) has no stable isotopes, but does have one very long-lived isotope; thus, the standard atomic weight can be given as.
Calcium (20Ca) has 24 isotopes, from 34Ca to 57Ca.
Hydrogen (1H) has three naturally occurring isotopes, sometimes denoted 1H, 2H, and 3H.
Lead (82Pb) has four stable isotopes: 204Pb, 206Pb, 207Pb, 208Pb.
Naturally occurring manganese (25Mn) is composed of 1 stable isotope, 55Mn.
Natural nitrogen (7N) consists of two stable isotopes, nitrogen-14, which makes up the vast majority of naturally occurring nitrogen, and nitrogen-15, which is less common.
Polonium (84Po) has 33 isotopes, all of which are radioactive, with between 186 and 227 nucleons.
Protactinium (91Pa) has no stable isotopes.
Radium (88Ra) has no stable or nearly stable isotopes, and thus a standard atomic weight cannot be given.
There are 35 known isotopes of radon (86Rn) from 195Rn to 229Rn; all are radioactive.
Naturally occurring rhenium (75Re) is 37.4% 185Re, which is stable, and 62.6% 187Re, which is unstable but has a very long half-life (41.2×109 years).
Silicon (14Si) has 25 known isotopes, with mass numbers ranging from 22 to 45.
There are 38 known isotopes and 17 nuclear isomers of tellurium (52Te), with atomic masses that range from 105 to 142.
Thallium (81Tl) has 37 isotopes with atomic masses that range from 176 to 212.
Although thorium (90Th) has 6 naturally occurring isotopes, none of these isotopes are stable; however, one isotope, 232Th, is relatively stable, with a half-life of 1.405×1010 years, considerably longer than the age of the Earth, and even slightly longer than the generally accepted age of the universe.
Isotopic labeling (or isotopic labelling) is a technique used to track the passage of an isotope (an atom with a detectable variation) through a reaction, metabolic pathway, or cell.
Isotropy is uniformity in all orientations; it is derived from the Greek isos (ἴσος, "equal") and tropos (τρόπος, "way").
Lambda, Λ, λ (uppercase Λ, lowercase λ; λάμ(β)δα lám(b)da) is the 11th letter of the Greek alphabet.
Leo Szilard (Szilárd Leó; Leo Spitz until age 2; February 11, 1898 – May 30, 1964) was a Hungarian-German-American physicist and inventor.
This list of nuclides shows observed nuclides that either are stable or, if radioactive, have half-lives longer than one hour.
These are lists of nuclear disasters and radioactive incidents.
Lithium (from lit) is a chemical element with symbol Li and atomic number 3.
Lulu Press, Inc., doing business as Lulu.com, is an online print-on-demand, self-publishing, and distribution platform.
The macroscopic scale is the length scale on which objects or phenomena are large enough to be visible almost practically with the naked eye, without magnifying optical instruments.
A magnetic field is a vector field that describes the magnetic influence of electrical currents and magnetized materials.
The mantle is a layer inside a terrestrial planet and some other rocky planetary bodies.
Marie Skłodowska Curie (born Maria Salomea Skłodowska; 7 November 18674 July 1934) was a Polish and naturalized-French physicist and chemist who conducted pioneering research on radioactivity.
Mass is both a property of a physical body and a measure of its resistance to acceleration (a change in its state of motion) when a net force is applied.
Mass in special relativity incorporates the general understandings from the laws of motion of special relativity along with its concept of mass–energy equivalence.
The mass number (symbol A, from the German word Atomgewichte (atomic weight), also called atomic mass number or nucleon number, is the total number of protons and neutrons (together known as nucleons) in an atomic nucleus. It determines the atomic mass of atoms. Because protons and neutrons both are baryons, the mass number A is identical with the baryon number B as of the nucleus as of the whole atom or ion. The mass number is different for each different isotope of a chemical element. This is not the same as the atomic number (Z) which denotes the number of protons in a nucleus, and thus uniquely identifies an element. Hence, the difference between the mass number and the atomic number gives the number of neutrons (N) in a given nucleus:. The mass number is written either after the element name or as a superscript to the left of an element's symbol. For example, the most common isotope of carbon is carbon-12, or, which has 6 protons and 6 neutrons. The full isotope symbol would also have the atomic number (Z) as a subscript to the left of the element symbol directly below the mass number:. This is technically redundant, as each element is defined by its atomic number, so it is often omitted.
In electronics and telecommunications, modulation is the process of varying one or more properties of a periodic waveform, called the carrier signal, with a modulating signal that typically contains information to be transmitted.
The mole, symbol mol, is the SI unit of amount of substance.
In Newtonian mechanics, linear momentum, translational momentum, or simply momentum (pl. momenta) is the product of the mass and velocity of an object.
In mathematics, a multiplicative calculus is a system with two multiplicative operators, called a "multiplicative derivative" and a "multiplicative integral", which are inversely related in a manner analogous to the inverse relationship between the derivative and integral in the classical calculus of Newton and Leibniz.
The National Council on Radiation Protection and Measurements (NCRP), formerly the National Committee on Radiation Protection and Measurements, and before that the Advisory Committee on X-Ray and Radium Protection (ACXRP), is a U.S. organization.
The National Physical Laboratory (NPL) is the national measurement standards laboratory for the United Kingdom, based at Bushy Park in Teddington, London, England.
A natural nuclear fission reactor is a uranium deposit where self-sustaining nuclear chain reactions have occurred.
In mathematics, the natural numbers are those used for counting (as in "there are six coins on the table") and ordering (as in "this is the third largest city in the country").
A nebula (Latin for "cloud" or "fog"; pl. nebulae, nebulæ, or nebulas) is an interstellar cloud of dust, hydrogen, helium and other ionized gases.
A neon lamp (also neon glow lamp) is a miniature gas discharge lamp.
A neutrino (denoted by the Greek letter ν) is a fermion (an elementary particle with half-integer spin) that interacts only via the weak subatomic force and gravity.
Neutron emission is a mode of radioactive decay in which one or more neutrons are ejected from a nucleus.
Nikola Tesla (Никола Тесла; 10 July 1856 – 7 January 1943) was a Serbian-American inventor, electrical engineer, mechanical engineer, physicist, and futurist who is best known for his contributions to the design of the modern alternating current (AC) electricity supply system.
The Nobel Prize in Physiology or Medicine (Nobelpriset i fysiologi eller medicin), administered by the Nobel Foundation, is awarded once a year for outstanding discoveries in the fields of life sciences and medicine.
Nuclear engineering is the branch of engineering concerned with the application of breaking down atomic nuclei (fission) or of combining atomic nuclei (fusion), or with the application of other sub-atomic processes based on the principles of nuclear physics.
In nuclear physics and nuclear chemistry, nuclear fission is either a nuclear reaction or a radioactive decay process in which the nucleus of an atom splits into smaller parts (lighter nuclei).
The nuclear force (or nucleon–nucleon interaction or residual strong force) is a force that acts between the protons and neutrons of atoms.
A nuclear isomer is a metastable state of an atomic nucleus caused by the excitation of one or more of its nucleons (protons or neutrons).
Nuclear medicine is a medical specialty involving the application of radioactive substances in the diagnosis and treatment of disease.
Nuclear pharmacy, also known as radiopharmacy, involves preparation of radioactive materials for patient administration that will be used to diagnose and treat specific diseases in nuclear medicine.
Nuclear physics is the field of physics that studies atomic nuclei and their constituents and interactions.
Nuclear power is the use of nuclear reactions that release nuclear energy to generate heat, which most frequently is then used in steam turbines to produce electricity in a nuclear power plant.
In nuclear physics and nuclear chemistry, a nuclear reaction is semantically considered to be the process in which two nuclei, or else a nucleus of an atom and a subatomic particle (such as a proton, neutron, or high energy electron) from outside the atom, collide to produce one or more nuclides that are different from the nuclide(s) that began the process.
A nuclear reactor, formerly known as an atomic pile, is a device used to initiate and control a self-sustained nuclear chain reaction.
Nuclear transmutation is the conversion of one chemical element or an isotope into another chemical element.
In chemistry and physics, a nucleon is either a proton or a neutron, considered in its role as a component of an atomic nucleus.
Nucleosynthesis is the process that creates new atomic nuclei from pre-existing nucleons, primarily protons and neutrons.
An order of magnitude of time is (usually) a decimal prefix or decimal order-of-magnitude quantity together with a base unit of time, like a microsecond or a million years.
In biology, an organism (from Greek: ὀργανισμός, organismos) is any individual entity that exhibits the properties of life.
Oscillation is the repetitive variation, typically in time, of some measure about a central value (often a point of equilibrium) or between two or more different states.
A particle accelerator is a machine that uses electromagnetic fields to propel charged particles to nearly light speed and to contain them in well-defined beams.
Particle decay is the spontaneous process of one unstable subatomic particle transforming into multiple other particles.
The particle number (or number of particles) of a thermodynamic system, conventionally indicated with the letter N, is the number of constituent particles in that system.
A patent medicine, also known as a nostrum (from the Latin nostrum remedium, or "our remedy") is a commercial product advertised (usually heavily) as a purported over-the-counter medicine, without regard to its effectiveness.
Paul Ulrich Villard (28 September 1860 – 13 January 1934) was a French chemist and physicist.
Phosphorescence is a type of photoluminescence related to fluorescence.
The photon is a type of elementary particle, the quantum of the electromagnetic field including electromagnetic radiation such as light, and the force carrier for the electromagnetic force (even when static via virtual particles).
Pierre Curie (15 May 1859 – 19 April 1906) was a French physicist, a pioneer in crystallography, magnetism, piezoelectricity and radioactivity.
In probability theory and statistics, the Poisson distribution (in English often rendered), named after French mathematician Siméon Denis Poisson, is a discrete probability distribution that expresses the probability of a given number of events occurring in a fixed interval of time or space if these events occur with a known constant rate and independently of the time since the last event.
In probability, statistics and related fields, a Poisson point process or Poisson process (also called a Poisson random measure, Poisson random point field or Poisson point field) is a type of random mathematical object that consists of points randomly located on a mathematical space.
Polonium is a chemical element with symbol Po and atomic number 84.
The positron or antielectron is the antiparticle or the antimatter counterpart of the electron.
Positron emission or beta plus decay (β+ decay) is a subtype of radioactive decay called beta decay, in which a proton inside a radionuclide nucleus is converted into a neutron while releasing a positron and an electron neutrino (νe).
Potassium-40 (40K) is a radioactive isotope of potassium which has a very long half-life of 1.251 years.
In geochemistry, geophysics and geonuclear physics, primordial nuclides, also known as primordial isotopes, are nuclides found on Earth that have existed in their current form since before Earth was formed.
Proton emission (also known as proton radioactivity) is a rare type of radioactive decay in which a proton is ejected from a nucleus.
In quantum physics, a quantum fluctuation (or vacuum state fluctuation or vacuum fluctuation) is the temporary change in the amount of energy in a point in space, as explained in Werner Heisenberg's uncertainty principle.
Quantum mechanics (QM; also known as quantum physics, quantum theory, the wave mechanical model, or matrix mechanics), including quantum field theory, is a fundamental theory in physics which describes nature at the smallest scales of energy levels of atoms and subatomic particles.
In quantum physics, quantum state refers to the state of an isolated quantum system.
Quantum tunnelling or tunneling (see spelling differences) is the quantum mechanical phenomenon where a particle tunnels through a barrier that it classically cannot surmount.
In physics, radiation is the emission or transmission of energy in the form of waves or particles through space or through a material medium.
Radiation therapy or radiotherapy, often abbreviated RT, RTx, or XRT, is therapy using ionizing radiation, generally as part of cancer treatment to control or kill malignant cells and normally delivered by a linear accelerator.
Radioactive contamination, also called radiological contamination, is the deposition of, or presence of radioactive substances on surfaces or within solids, liquids or gases (including the human body), where their presence is unintended or undesirable (from the International Atomic Energy Agency - IAEA - definition).
Radioactive decay (also known as nuclear decay or radioactivity) is the process by which an unstable atomic nucleus loses energy (in terms of mass in its rest frame) by emitting radiation, such as an alpha particle, beta particle with neutrino or only a neutrino in the case of electron capture, gamma ray, or electron in the case of internal conversion.
The law of radioactive displacements, also known as Fajans and Soddy law, in radiochemistry and nuclear physics, is a rule governing the transmutation of elements during radioactive decay.
Radioactive quackery is quackery that improperly promotes radioactivity as a therapy for illnesses.
Radioactivity is generally used in life sciences for highly sensitive and direct measurements of biological phenomena, and for visualizing the location of biomolecules radiolabelled with a radioisotope.
A radiogenic nuclide is a nuclide that is produced by a process of radioactive decay.
Radiometric dating or radioactive dating is a technique used to date materials such as rocks or carbon, in which trace radioactive impurities were selectively incorporated when they were formed.
A radionuclide (radioactive nuclide, radioisotope or radioactive isotope) is an atom that has excess nuclear energy, making it unstable.
Radium is a chemical element with symbol Ra and atomic number 88.
Radon is a chemical element with symbol Rn and atomic number 86.
Randomness is the lack of pattern or predictability in events.
In special relativity the rest frame of a particle is the coordinate system (frame of reference) in which the particle is at rest.
Rhenium is a chemical element with symbol Re and atomic number 75.
Rock or stone is a natural substance, a solid aggregate of one or more minerals or mineraloids.
Rolf Maximilian Sievert (6 May 1896 – 3 October 1966) was a Swedish medical physicist whose major contribution was in the study of the biological effects of ionizing radiation.
In chemistry, a salt is an ionic compound that can be formed by the neutralization reaction of an acid and a base.
The second law of thermodynamics states that the total entropy of an isolated system can never decrease over time.
In nuclear physics, secular equilibrium is a situation in which the quantity of a radioactive isotope remains constant because its production rate (e.g., due to decay of a parent isotope) is equal to its decay rate.
The sievert (symbol: SvNot be confused with the sverdrup or the svedberg, two non-SI units that sometimes use the same symbol.) is a derived unit of ionizing radiation dose in the International System of Units (SI) and is a measure of the health effect of low levels of ionizing radiation on the human body.
A solar flare is a sudden flash of increased Sun's brightness, usually observed near its surface.
The Solar SystemCapitalization of the name varies.
In quantum mechanics and particle physics, spin is an intrinsic form of angular momentum carried by elementary particles, composite particles (hadrons), and atomic nuclei.
Spontaneous emission is the process in which a quantum mechanical system (such as an atom, molecule or subatomic particle) transitions from an excited energy state to a lower energy state (e.g., its ground state) and emits a quantum in the form of a photon.
Spontaneous fission (SF) is a form of radioactive decay that is found only in very heavy chemical elements.
Springer Publishing is an American publishing company of academic journals and books, focusing on the fields of nursing, gerontology, psychology, social work, counseling, public health, and rehabilitation (neuropsychology).
The term stable isotope has a meaning similar to stable nuclide, but is preferably used when speaking of nuclides of a specific element.
Stable nuclides are nuclides that are not radioactive and so (unlike radionuclides) do not spontaneously undergo radioactive decay.
A star is type of astronomical object consisting of a luminous spheroid of plasma held together by its own gravity.
Statistical mechanics is one of the pillars of modern physics.
The word stochastic is an adjective in English that describes something that was randomly determined.
A storage ring is a type of circular particle accelerator in which a continuous or pulsed particle beam may be kept circulating typically for many hours.
A supernova (plural: supernovae or supernovas, abbreviations: SN and SNe) is a transient astronomical event that occurs during the last stellar evolutionary stages of a star's life, either a massive star or a white dwarf, whose destruction is marked by one final, titanic explosion.
Supernova nucleosynthesis is a theory of the nucleosynthesis of the natural abundances of the chemical elements in supernova explosions, advanced as the nucleosynthesis of elements from carbon to nickel in massive stars by Fred Hoyle in 1954.
In chemistry, a synthetic element is a chemical element that does not occur naturally on Earth, and can only be created artificially.
Tau (uppercase Τ, lowercase τ; ταυ) is the 19th letter of the Greek alphabet.
Tellurium is a chemical element with symbol Te and atomic number 52.
Two physical systems are in thermal equilibrium if there are no net flow of thermal energy between them when they are connected by a path permeable to heat.
Thorium is a weakly radioactive metallic chemical element with symbol Th and atomic number 90.
In physics and engineering, the time constant, usually denoted by the Greek letter τ (tau), is the parameter characterizing the response to a step input of a first-order, linear time-invariant (LTI) system.
In nuclear physics, transient equilibrium is a situation in which equilibrium is reached by a parent-daughter radioactive isotope pair where the half-life of the daughter is shorter than the half-life of the parent.
Tritium (or; symbol or, also known as hydrogen-3) is a radioactive isotope of hydrogen.
Unicode is a computing industry standard for the consistent encoding, representation, and handling of text expressed in most of the world's writing systems.
Uranium is a chemical element with symbol U and atomic number 92.
Uranium-234 is an isotope of uranium.
Vanderbilt University (informally Vandy) is a private research university in Nashville, Tennessee.
In particle physics, the weak interaction (the weak force or weak nuclear force) is the mechanism of interaction between sub-atomic particles that causes radioactive decay and thus plays an essential role in nuclear fission.
Wilhelm Conrad Röntgen (27 March 1845 – 10 February 1923) was a German mechanical engineer and physicist, who, on 8 November 1895, produced and detected electromagnetic radiation in a wavelength range known as X-rays or Röntgen rays, an achievement that earned him the first Nobel Prize in Physics in 1901.
William Herbert Rollins is a forgotten American scientist and dentist.
World War II (often abbreviated to WWII or WW2), also known as the Second World War, was a global war that lasted from 1939 to 1945, although conflicts reflecting the ideological clash between what would become the Allied and Axis blocs began earlier.
The Wu experiment was a nuclear physics experiment conducted in 1956 by the Chinese American physicist Chien-Shiung Wu in collaboration with the Low Temperature Group of the US National Bureau of Standards.
X-rays make up X-radiation, a form of electromagnetic radiation.
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