]> This ontology covers classes and properties in the field of physics that are commonly used by astronomers. It includes terms from the IVOA Thesaurus plus terms from the UMD astronomical ontology Ed Shaya physics.owl ablation burn away absolute temperature scale absorption absorption coefficient absorptivity acceleration acoustics acoustic wave sound sound wave adiabatic process adsorption albedo spherical albedo reflectivity Alfven surface Alfven wave hydromagnetic wave alpha particle angular momentum angular velocity antimatter antineutrino antinucleon antiparticle antiproton atom atomic isotope atomic line atomic nucleus nuclei [atoms] atomic physics atomic process axion baryon black body radiation thermal black body radiation Bose-Einstein Condensate Bose-Einstein statistics boson bottom quark boundary layer bound-free transition bound free transition bow shock bremsstrahlung free free transition free-free transition brillouin scattering brillouin spectrum caustic caustic crossing celsius temperature scale center of mass The most common temperature scale for scientific work. The freezing point of water is 0 degrees and the boiling point of water is 100 degrees in this system. centrifugal force centripetal force Cerenkov radiation Cerenkov effect Chandrasekhar-Schoenberg limit Chandrasekhar-Schonberg limit Schonberg-Chandrasekhar limit Schoenberg-Chandrasekhar limit charm quark circular polarization circular polarisation UK cluster coherence collision collision process collisional excitation collisional plasma collision broadening collision process collisional process collision strength Compton effect Compton scattering Compton wavelength condensation conductance quantum is the quantized unit of conductance. It is defined by \frac{2e^2}{h} conduction convection cooling current current sheet cyclotron radiation damping constant deceleration degenerate matter density specific gravity differential rotation diffraction diffraction patterns diffusion dimension dipole dipole strength dispersion dissipation Doppler broadening Doppler effect top quark drift wave dynamical time dynamics dynamo theory Einstein coefficient Einstein effect Einstein shift elasticity electrical property electric charge electric constant electric current electric dipole electric dipole strength electric field electricity electrodynamics electromagnetic electron electron electron beam electron density electron gyromagnetic ratio electronic state electronic transition electron magnetic moment electron pumping electron temperature electrostatic wave elementary particle elementary particle scattering electromagnetic field electromagnetic field emerging flux electromagnetic field electromagnetic force electromagnetic interaction emission emission coefficient emissivity electromagnetic radiation electromagnetic wave electromagnetic theory energetic particle energy energy content energy density energy distribution energy level energy source energy spectrum energy-transfer energy transfer enthalpy entropy e-process equation of state equilibrium figure equipotential surface escape velocity evaporation excitation extreme ultraviolet radiation EUV Faraday effect far infrared radiation far ultraviolet radiation FUV Fermi interaction fermion Fermionic Condensate Fermi Dirac nucleus Feynman diagram Feynman integral field equation field of optics fine structure fission flow instability fluid dynamics fluid mechanics fluorescence flux flux density focal length Fokker-Planck equation Fokker Planck equation forbidden transition force free-bound emission free bound emission free-free emission free free emission friction fundamental frequency The lowest characteristic frequency of oscillation of a dynamical system. fundamental mode fundamental particle fusion future light cone gamma-ray radiation gamma-ray gamma radiation gamma-ray scattering gamma ray scattering gamma-ray spectrum gamma ray spectrum gas distribution gas dynamics gas kinematics gaseous disk gaseous sphere general theory of relativity g-factor gluon gravitating disk gravitation gravitational constant gravitational effect gravitational energy gravitational field gravity field gravitational force force of gravity gravitational redshift gravitational wave graviton gravity acceleration of gravity gravity wave gyromagnetic ratio gyrosynchrotron radiation hadron hadron barrier half-wave dipole half wave dipole halfwave dipole Hanle effect The Hanle Effect describes resonant line scattering polarization in a magnetic medium. harmonic frequency harmonic overtones harmonics Hawking radiation heat-transfer high-energy radiation high energy radiation high-temperature hot high temperature hydrodynamics hydrostatic equilibrium infrared infrared emission infrared radiation intensity specific intensity interference wave internal motion inverse Compton effect inverse Compton scattering inverse maser ionizing shock wave ion plasma wave irradiance isothermal sphere Jeans length Jeans mass jump condition kinematics kinetic energy lepton light absorption light coherence light cone light emission light interference light polarization polarization wave light scattering line shift spectral line shift local thermodynamic equilibrium LTE low-temperature plasma luminescence candoluminescence luminosity macroturbulence magnetic dipole strength magnetic field magnetic moment magnetic moment anomaly magnetic monopole magnetic pole magnetic property magnetohydrodynamics MHD hydromagnetics maser mass mass density mass distribution matter meson microwave microwave emission microwave radiation microwave spectrum Mie scattering millimeter radiation millimeter wave mm radiation MOdified Newtonian Dynamics MOND momentum motion muon muon neutrino naked singularity near infrared radiation near ultraviolet radiation NUV neutral gas neutrino neutron Newtonian gravitation non-equilibrium flow nonequilibrium flow non-radial pulsation nonradial pulsation non-thermal radiation nonthermal radiation nuclear fission nuclear fusion nuclear physics nuclear radiation nuclear reaction nutation oblique rotator opacity optical radiation optical pathlength optical property oscillation oscillator strength f value f-value overtone frequency harmonic overtones overtones overtone mode overtones pair annihilation pair production particle particle acceleration particle accretion particle beam particle creation particle density particle interaction particle mass particle production Paschen-Back effect the Paschen-Back effect is the splitting of atomic energy levels in the presence of a strong magnetic field. This occurs when an external magnetic field is sufficiently large to disrupt the coupling between orbital and spin angular momenta. This effect is the strong field generalization of the Zeeman effect. past light cone p branch A set of lines in the spectra of molecules corresponding to unit increases in rotational energy. Penrose process phase space phosphorescence photon physical constant fundamental constant physical distance pion pixel picture element voxel Planck black body formula Planck constant plane polarization linear polarization plane polarisation UK plasma cosmic plasma plasma loop plasma physics plasma wave Poincare theorem polarization charge separation polarized light polarized radiation polarised light UK polytrope population inversion positron potential energy potential theory power Poynting-Robertson effect Poynting Robertson effect p process precession precursor pulse pressure pressure broadening proton pulsation mode pulse pulse duration pulse energy pulse intensity pulse profile pulse structure pulse width pulse window q branch quanta quantum quantization quantisation UK quantum field theory quantum mechanics quantum theory quark radial pulsation radial velocity radiation radiation damping radiation field radiation measurement radiation mechanism radiation pressure radiation scattering electromagnetic wave scattering radiative equilibrium radiative recombination radiative capture radiative transfer radio absorption radioactive decay radioactivity radio emission radio frequency radio radiation radio wave radio recombination line radio spectrum Raman scattering Rankine-Hugoniot relation Rayleigh Rayleigh criterion Rayleigh limit Rayleigh limit Rayleigh number Rayleigh scattering Rayleigh-Taylor instability Razin effect The presence of a thermal plasma in the emitting region means that the refractive index of the medium is less than unity and the phase velocity of electromagnetic waves is greater than $c$. As a result, synchrotron radiation is suppressed at frequencies where the refractive index becomes significantly less than 1. This is often called Tsytovich-Razin effect. The consequence is a low-frequency cutoff near \begin{displaymath} \rm { {\nu_{R}} = {{4 c n e} \over {3 B_{\bot}}} = {{2\nu_{p... ... \nu_{0}}} \sim {{2 \times 10^{-5} n} \over {B_{\bot}}} MHz} \end{displaymath} reference frame refraction refraction angle angle of refraction refractive index relativistic effect relativistic electron relativistic fluid dynamics relativistic mechanics relativistic particle relativistic plasma relativistic gas relativistic velocity relativity retardation rigid body rotation rotating body rotating shell rotation rotational velocity scattering Schwarzschild metric Schwarzschild radius scintillation self-absorption self absorption shock shock wave singularity sound speed speed of sound space-time curvature space-time singularity special theory of relativity spectrum s-process s process Stark broadening stimulated emission stimulated radiation stokes parameter strange quark strong interaction subatomic particle submillimeter radiation submillimeter wave symmetry breaking synchrotron radiation physical system physical system tangential velocity tau particle tau neutrino particle temperature temperature fluctuation temperature scale thermal conductivity thermal emission thermal equilibrium thermal instability thermal property thermal radiation thermal stability thermal structure thermionic emission dark current thermodynamic equilibrium thermodynamics thermoluminescence thermonuclear reaction Thomson scattering three-body problem three body problem three-dimensional spectrum three dimensional spectrum top quark transition probability transmission transparency transport process two-dimensional spectrum two dimensional spectrum ultraviolet UV ultraviolet radiation ultraviolet_light up quark vacuum velocity velocity dispersion velocity distribution velocity ellipsoid velocity field velocity of light speed of light velocity space vibration vibrational spectrum virial theorem viscosity visible radiation light visible spectrum waveform analysis wavelength wave measurement wave motion wave propagation weak gauge boson weak interaction W- W+ X-ray absorption X-ray diffraction X-ray emission X-ray fluorescence X-ray polarization X-ray radiation X-ray X-ray scattering X-ray spectroscopy X-ray spectrum Zeeman splitting spectral line splitting line splitting Z0 With Respect To. Velocity is a motion with respect to some other Thing. Number of Protons This allows giving a frequency, wavelength or Energy for the reference Amplitude. s d f p F D P S Kelvin Temperature scale used for ordinary purposes in the United State Conversion from Centigrade is Centigrade*9/5 + 32. Celsius