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An energy causing the acceleration of the expansion of the universe, detectable through its gravitational effects.
- 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
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Matter not visible to us because it emits no radiation that we can observe, but it is detectable gravitationally. A small fraction of it is baryonic, e.g. dim stars, cool gas, etc.
- 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
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Decreasing the velocity (of expansion).
- 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
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Regions of greater and lesser mass density, which can form into structure such as galaxies, clusters, etc.
- Browse Related Terms: Cluster, Density Fluctuations in Matter, Galaxy, Globular Clusters, Inhomogeneity, Large Scale Structure, local group, Structure, Super Cluster
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A special form of hydrogen (an isotope called "heavy hydrogen") that has a neutron as well as a proton in its nucleus.
- Browse Related Terms: Atoms, Baryon, deuterium, Extrapolate, Fission, Isotopes, Neutron, Nucleon, Nucleus/Nuclei, Primordial Nucleosynthesis, Synthesis of Nuclei
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apparent change in frequency of a wave due to the relative motion of the source and observer. For example, when they move apart the wavelength is stretched making the frequency lower.
- Browse Related Terms: Acceleration, Doppler Effect, evolution, Fluctuation, Phase Transition, Redshift, Velocity
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Changes over a length of time.
- Browse Related Terms: Dynamics, Finite, H0, Hubble Constant, Initial Conditions, Intensity, Light Year, Nought, static, Visible Universe
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