Alpha particles
~ a form of particle radiation which has low penetration. They consist of two protons and two neutrons bound together tightly into a particle identical to that of a helium nucleus. Alpha particles are emitted by radioactive nuclei such as uranium or radium in a process known as alpha decay. The physicist Ernest Rutherford used Alpha particles at the Cavendish Laboratory, UK, to investigate and probe for a theoretical nucleus to the then, little known, structure of the atom. It is ironic, that at this time, the Alpha particle was used to help discover the atomic nucleus, and lead to the discoveries of protons and neutrons, despite little being known regarding the particle itself, and that it was comprised of exactly these things.

Antimatter
~ antiparticles give rise to antimatter, the antithesis of matter. If a particle and it's antiparticle come into contact with each other, the two annihilate, and are converted into energy or other exotic particles with equal energy in accordance with Einstein's equation E=MC². Antimatter is not found naturally on Earth, except very briefly, and in vanishingly small quantities, (as the result of radioactive decay or "cosmic rays").

Antineutron
~ antiparticle of the neutron. Discovered by Bruce Cork, 1956.

Antiproton
~ antiparticle of the proton. Discovered in 1955 by Emilio Segre and Owen Chamberlain, [1959 Nobel Prize in Physics].

Boson
~ In particle physics, bosons are force carrier particles, such as the photon. They may be either elementary or composite. They are distinguished from fermions (matter particles) by their integer spin. Bosons are named after Indian physicist Satyendra Nath Bose.

Brane cosmology
~ refers to several theories in particle physics and cosmology motivated by, but not rigorously derived from, "superstring theory" and "M-theory". The central idea is that our visible, four-dimensional Universe is entirely restricted to a brane inside a higher-dimensional space, and that other brane's exist and may interact together. This model proposes to explain the weakness of gravity, and gravitational force, relative to the other fundamental forces of nature, found in our Universe, dimension, or brane. It proposes that gravity may be free to "leak" into our physical Universe, and interact, yet only on a limited degree.

Deuterium
~ isotope of hydrogen, that also contains a single neutron in the nucleus. The isotope was discovered by Harold Urey in 1931. D₂O is commonly known as "heavy water".

Electromagnetism
~ Discovered with the early experimentation into electricity, and later proposed as the fundamental force of all electrical charge and properties of an atom.

Electromagnet
~ Uses the electro-magnetic properties of the atom, and electricity, to provide a switchable and controllable form of non-permanent magnet. Extensively incorporated in electrical machines such as generators, motors and solenoids.

Electron
~ subatomic particle that surrounds the nucleus of an atom, and carries a negative electric charge. Particle class = Lepton. Discovery credited to J.J. Thomson at the Cavendish Laboratory, UK, in 1897.

Fermion
~ a particle of matter with a half-integer spin. These include the leptons, baryons (protons and neutrons - composite fermions composed of quarks) and quarks. All fermions obey the "Fermi-Dirac statistics", and the "Pauli exclusion principle", and interact by exchanging bosons (particles of force).

Gamma rays
~ are forms of "electromagnetic radiation" or light emissions of a specific frequency produced from sub-atomic particle interaction, such as "electron-positron annihilation" and "radioactive decay"; most usually generated from nuclear reactions occurring within the interstellar medium of space. They are often characterised as being light with the highest frequency and energy within the light spectrum. Due to their high energy content, they are able to cause serious damage when absorbed by living cells. Gamma rays are also able to penetrate dense materials.

Gravitation
~ is a phenomenon through which all objects attract each other. Modern physics describes gravitation using the "general theory of relativity", (Einstein), yet "Newton's law of universal gravitation" still provides sufficient approximation for calculating the effects of gravity upon large bodies, such as planets and stars. The phenomenon is still not fully understood, and theories also include; the existence of a gravitational particle, (Graviton, Higgs/Boson or "God" particle); and models proposing that gravity or the gravitational force is "leaking" from another dimension, (Brane theory).

Graviton
~ a hypothetical elementary particle that mediates the force of gravity in the framework of "quantum field theory". If it exists, the graviton must be massless (because the gravitational force has unlimited range). Describing the behavior of all other forces of nature with similar particles: "electromagnetism" with the photon, the "strong interaction" with the gluons, and the "weak interaction" with the W & Z bosons; proposes that, the gravitational interaction may be mediated by gravitons, instead of being described in terms of curved spacetime like in general relativity.

Gravity
~ the force of attraction between all masses and matter, in the Universe. The property of gravitational force.

Heavy water
~ refers to deuterium oxide, D₂O or ²H₂O. The physical and chemical properties are somewhat similar to those of water, H₂O. The hydrogen atoms are of the "heavy" isotope deuterium, in which the nucleus contains an additional neutron, together with the single proton found in the nucleus of the hydrogen atom. (The hydrogen atomic nucleus does not contain a neutron, only a single proton).

Lepton
~ is a fermion with a spin of ¹/₂ integer, that does not experience the "strong nuclear force", thus leptons are elementary particles distinct from the other fermion family known as quarks. The three flavors of leptons are the electron, the muon and the tau, along with their pairs (neutrino) and antiparticles (positron and electron antineutrino).

Magnetism
~ fundamental forces that arise from the movement of electrical charge. Commonly understood as the properties of a material to exert force of attraction and repulsion to alike materials, such as iron.

Marie Curie
[1867-1934], Polish physicist and chemist, leading proponent, [together with Pierre Curie - spouse], in the investigation of Radioactivity. Credited for the discovery of Radium and Polonium. Nobel prize winner Physics - 1903, and again for Chemistry - 1911. Studied and worked in Paris, France. First woman appointed to teach at the Sorbonne.

Neutron
~ subatomic particle that resides in the nucleus of an atom, and carries a neutral electric charge. Particle class = Baryon. Discovery credited to James Chadwick at the Cavendish Laboratory, UK, in 1932. Outside the nucleus, free neutrons are unstable and decay by emitting an electron and antineutrino to become a proton.

Photon
~ is the elementary particle responsible for electromagnetic phenomena, or "light", and mediates electromagnetic interactions in atoms and matter. The photon has "zero invariant mass" and travels at the constant speed C, (the speed of light in empty space). However, in the presence of matter, a photon can be slowed or even absorbed, transferring energy and momentum proportional to it's frequency. Like all quanta, (of energy), the photon has both wave and particle properties; thus it exhibits "wave-particle duality". A photon belongs to the force carrying particle family, known as bosons.

Positron
~ is the antiparticle or the antimatter counterpart of the electron. A positron may be generated by "positron emission radioactive decay", or by the interaction of a photon with a charged particle; this process is called "pair production", as it generates one electron and one positron from the energy of the photon. The positron was the first evidence of antimatter, and was discovered by Carl D. Anderson in 1932. By passing "cosmic rays" through a gas chamber, together with a lead plate surrounded by a magnetic field, Anderson distinguished the particles by bending the differently charged particles in different directions.

Positron emission
~ is a type of beta decay, sometimes referred to as "beta plus" (ß+); whereby, a proton is converted to a neutron via the "weak nuclear force", and a beta plus particle (a positron) and a neutrino are emitted.

Proton
~ subatomic particle that resides in the nucleus of an atom, and carries a positive electric charge. Particle class = Fermion. Discovery credited to Ernest Rutherford at the Cavendish Laboratory, UK, in 1918.

Quantum mechanics
~ (or quantum theory) is a physical science dealing with the behaviour of matter and waves on the scale of atoms and subatomic particles. It also forms the basis for the contemporary understanding of how large objects such as stars and galaxies, and cosmological events such as the "Big Bang", can be analyzed and explained. Quantum mechanics is the basis of modern developments in chemistry, molecular biology, and electronics, and the foundation for the technology that has transformed the world in the last sixty years. The term "quantum mechanics" was first coined by Max Born in 1924.

Quark
~ fundamental subatomic particle that is constituent in the construct of nucleons - Protons and Neutrons, as well as other Hadrons. Particle class = Lepton. Quark's are defined into six different types or 'flavours', [up, down, strange, charm, bottom, and top], and different combinations of these govern the constituent construct of different atomic particles. Discovery credited to both Murray Gell-Mann and Kazuhiko Nishijima, independently, 1961.

Radiation
~ is the process of emitting energy in the form of "waves" or "particles". Various types of radiation may be distinguished, depending on the properties of the emitted energy/matter, the type of the emission source, properties, and purposes of the emission. Examples include; Alpha, Beta, Gamma, Neutron, infrared and ultraviolet.

Radioactive decay
~ is the processes by which unstable atomic nuclei emit subatomic particles (radiation). This is a random process, and it is impossible to predict the decay of individual atoms. However, the decay probability can be predicted with accuracy, and the "half life" of a radioactive material can be established. Radioactivity was first discovered in 1896 by the French scientist Henri Becquerel while working on phosphorescent materials. The SI unit for measuring radioactivity is the becquerel (Bq).

Spacetime
~ is a mathematical model that combines space and time into a single construct called the "space-time continuum". Spacetime is usually interpreted with space being three-dimensional, and time playing the role of the fourth dimension. Since all physical objects; planets, stars, galaxies, particles, matter, exist within a three dimensional position and a place or position in time - this fourth dimensional quality cannot be ignored or excluded from establishing the exact position of a body. Thus the combined geometry of Space-time.

Wormhole
~ a Wormhole is a theoretical and mathematical model, that posits the possibility of connecting two distinct or distant regions of space, by "folding" or "collapsing" space and time, (space-time). A description of black holes describes wormholes at their centers, called "Einstein-Rosen bridges" after Einstein and his collaborator Nathan Rosen. However, this type of wormhole cannot be traversed because the center of a black hole is a "singularity", a point of infinite spacetime curvature, where the gravity would also be infinite, and all matter would be crushed to it's most fundamental constituents.