All > Science > Astronomy > Astrophysics
A rapid, accelerating expansion occuring in the early universe in some cosmological models, which solves several problems of cosmology.
- Browse Related Terms: Cosmological Constant, Λ, Critical Density, Dark Energy, Deceleration, Energy Density, inflation, Lambda, Λ, Matter-Dominated Universe, model, Quantum Fluctuations, Radiation-Dominated Universe, scalar, Steady State Theory
Also listed in:
- All > Business > Finance
- All > Business > Finance > Personal Finance
- All > Business > Finance > Personal Finance > Income Tax
- All > Business > Finance > Personal Finance > Retirement
- All > Business > Real Estate
The range of invisible radiation wavelengths from about 700 nm, just longer than red in the visible spectrum, to 1 mm, on the border of the microwave region.
- Browse Related Terms: 171, Electromagnetic Spectrum, Faculae, Gamma Rays, Infrared, Infrared (IR) Radiation, Ionization, radiation, Radio Waves, Solar Flare, Solar Ultraviolet Irradiance, Spectrograph, spectrum, Ultraviolet, Visible Light, Wavelength, X-Rays
Also listed in:
- All > Technology > Security > Biometrics
Infrared (IR) radiation is electromagnetic radiation whose wavelength is longer than that of visible light, but shorter than microwaves. The name means "below red".
- Browse Related Terms: 171, Electromagnetic Spectrum, Faculae, Gamma Rays, Infrared, Infrared (IR) Radiation, Ionization, radiation, Radio Waves, Solar Flare, Solar Ultraviolet Irradiance, Spectrograph, spectrum, Ultraviolet, Visible Light, Wavelength, X-Rays
All > Science > Astronomy > Astrophysics
Something not evenly distributed in space; a clump or cluster.
- Browse Related Terms: Cluster, Density Fluctuations in Matter, Galaxy, Globular Clusters, Inhomogeneity, Large Scale Structure, local group, Structure, Super Cluster
All > Science > Astronomy > Astrophysics
Being first, before anything else occurs.
- Browse Related Terms: Angular resolution, Equilibrium, Feed, Fusion, hypothesis, initial, Kelvin, Mid-Class Explorer (MIDEX), Nucleosynthesis, Quantum Mechanics, Simultaneous
Also listed in:
All > Science > Astronomy > Astrophysics
The nature of a system's state when time equals zero.
- Browse Related Terms: Dynamics, Finite, H0, Hubble Constant, Initial Conditions, Intensity, Light Year, Nought, static, Visible Universe
All > Science > Astronomy > Astrophysics
With regards to light, intensity is the energy moving through a region of area per unit of time. Intensity is proportional to the light's photon density, meaning the number of photons contained in a square meter. For example, if a beam of light has 10 photons passing through a square centimeter every second, that is twice the intensity of a beam with 5 photons passing through the same area every second.
- Browse Related Terms: Dynamics, Finite, H0, Hubble Constant, Initial Conditions, Intensity, Light Year, Nought, static, Visible Universe
Also listed in:
- All > Technology > Defense
All > Science > Astronomy > Astrophysics
A measure of the true brightness of an object. It is the amount of energy radiated into space every second by a celestial object, such as a star. We tend to use this interchangably with the Luminosity and Power of a star.
- Browse Related Terms: Angular Size, Apparent luminosities, Constant of Proportionality, Dark Matter, Flux, Heavenly Bodies, Intrinsic Luminosity, Inverse Square, Luminosity, Main Sequence Star, Observed Brightness, Parallax, Parsec, Relative Brightness, Standard Candle, Type Ia Supernova, Variable Stars
All > Science > Astronomy > Astrophysics
- 1 divided by a quantity squared. 1/(r^2). The force due to gravity is proportional to 1 over distance squared. F~1/(d2).
- Browse Related Terms: Angular Size, Apparent luminosities, Constant of Proportionality, Dark Matter, Flux, Heavenly Bodies, Intrinsic Luminosity, Inverse Square, Luminosity, Main Sequence Star, Observed Brightness, Parallax, Parsec, Relative Brightness, Standard Candle, Type Ia Supernova, Variable Stars
An atom or molecule that has lost or gained one or more electrons and has become electrically charged as a result.
- Browse Related Terms: Auroral Substorms, Cosmic Ray, Electromagnetic Radiation, Electron, Energetic Particles, Ion, Ion, Ionize, Ionosphere, Magnetism, plasma, Proton
All > Science > Astronomy > Astrophysics
Atomic matter that has unequal number of positive and negative charges, so its net charge is not zero.
Also listed in:
- All > Science > Biotechnology and Genetics > Food Biotechnology
- All > Science > Energy
- All > Science > Nuclear Physics
- All > Science > Water
- All > Science > Weather > Climate Change
An ion is an atom which has lost or gained one or more electrons so that it has a net electrical charge. Normally atoms have equal numbers of negatively charged electrons and positively charged protons so that the total charge of the atom is zero.
- Browse Related Terms: Auroral Substorms, Cosmic Ray, Electromagnetic Radiation, Electron, Energetic Particles, Ion, Ion, Ionize, Ionosphere, Magnetism, plasma, Proton
A process that produces ions, typically collisions between atoms or electrons, or by interaction with electromagnetic radiation.
- Browse Related Terms: 171, Electromagnetic Spectrum, Faculae, Gamma Rays, Infrared, Infrared (IR) Radiation, Ionization, radiation, Radio Waves, Solar Flare, Solar Ultraviolet Irradiance, Spectrograph, spectrum, Ultraviolet, Visible Light, Wavelength, X-Rays
Also listed in:
- All > Technology > Defense
All > Science > Astronomy > Astrophysics
The state in which an atom is missing on or more of its electrons, and is therefore positively charged. An ionized gas is one in which some or all of the atoms are ionized, rather than electrically neutral. The ionized electrons behave as free particles in this gas.
- Browse Related Terms: Annihilated/annihilation, Antimatter, Antiparticle/antiquark/antielectron, Coupled to Radiation, Electromagnetic Force, Electron, Ion, Ionized, Muon, Neutrino, plasma, Positron, Radiation Gas
The region of Earth's atmosphere that extends from about 50 to 300 miles above the surface of the planet and is made up of multiple layers dominated by electrically charged, or ionized, atoms.
- Browse Related Terms: Auroral Substorms, Cosmic Ray, Electromagnetic Radiation, Electron, Energetic Particles, Ion, Ion, Ionize, Ionosphere, Magnetism, plasma, Proton
Also listed in:
The amount of radiant energy from a selected source that falls on a surface in a given amount of time.
- Browse Related Terms: Convective Zone, Granules, Irradiation, Solar Spectral Irradiance (SSI), Sunspot Cycle, Total Solar Irradiance
Also listed in:
All > Science > Astronomy > Astrophysics
atoms that have the same number of protons, but a different number of neutrons are isotopes of each other.
- Browse Related Terms: Atoms, Baryon, deuterium, Extrapolate, Fission, Isotopes, Neutron, Nucleon, Nucleus/Nuclei, Primordial Nucleosynthesis, Synthesis of Nuclei
All > Science > Astronomy > Astrophysics
the property of being independent of direction. Isotropic radiation has the same intensity regardless of the direction of measurement.
Also listed in:
- All > Science > Weather
- All > Science > Weather > Climate Change
- All > Technology > Defense