Discovery of cosmic microwave background radiation
History of the Big Bang theory
Timeline of cosmological theories
Category
Astronomy portal
v
t
e
In modern cosmological theory, diffusion damping, also called photon diffusion damping, is a physical process which reduced density inequalities (anisotropies) in the early universe, making the universe itself and the cosmic microwave background radiation (CMB) more uniform. Around 300,000 years after the Big Bang, during the epoch of recombination, diffusing photons travelled from hot regions of space to cold ones, equalising the temperatures of these regions. This effect is responsible, along with baryon acoustic oscillations, the Doppler effect, and the effects of gravity on electromagnetic radiation, for the eventual formation of galaxies and galaxy clusters, these being the dominant large scale structures which are observed in the universe. It is a damping by diffusion, not of diffusion.[1]
The strength of diffusion damping is calculated by a mathematical expression for the damping factor, which figures into the Boltzmann equation, an equation which describes the amplitude of perturbations in the CMB.[2] The strength of the diffusion damping is chiefly governed by the distance photons travel before being scattered (diffusion length). The primary effects on the diffusion length are from the properties of the plasma in question: different sorts of plasma may experience different sorts of diffusion damping. The evolution of a plasma may also affect the damping process.[3] The scale on which diffusion damping works is called the Silk scale and its value corresponds to the size of galaxies of the present day. The mass contained within the Silk scale is called the Silk mass and it corresponds to the mass of the galaxies.[4]
^Hu, Sugiyama & Silk (1996-04-28), p. 2
^Cite error: The named reference jungman24 was invoked but never defined (see the help page).
^Cite error: The named reference hu1213 was invoked but never defined (see the help page).
^Cite error: The named reference madsen99101 was invoked but never defined (see the help page).
It is a damping by diffusion, not of diffusion. The strength of diffusiondamping is calculated by a mathematical expression for the damping factor, which...
narrow frequency range. Damping serves to reduce resonance in the room, by absorption or redirection through reflection or diffusion. Absorption reduces the...
Diffuse reflection Diffusiondamping Global dimming Medical optical imaging Optical tomography Radiative transfer equation and diffusion theory for photon...
by two effects: acoustic oscillations and diffusiondamping (also called collisionless damping or Silk damping). The acoustic oscillations arise because...
coherent transport through the diffusive damping. To quantify these statements, we may write down the diffusive damping time as τ D = 1 k ⊥ 2 D , {\displaystyle...
two effects: acoustic oscillations and diffusiondamping. The latter is also called collisionless or Silk damping after Joseph Silk. 1972 and 1974 Sloan...
(1942–) explained the homogeneity of the early universe using photon diffusiondamping Willem de Sitter (1872–1934) developed a theory of dark matter with...
{\displaystyle k_{d}\,\!} is the diffusion constant, and S {\displaystyle S\,\!} is slope. For steep slopes, diffusional sediment flux is more appropriately...
The Kodak verifax is a photo copying approach that uses a wet colloidal diffusion transfer technique patented by Yutzy, H.C. and Yackel, E.C. (1947) The...
Osmosis (/ɒzˈmoʊsɪs/, US also /ɒs-/) is the spontaneous net movement or diffusion of solvent molecules through a selectively-permeable membrane from a region...
absorb sound. Acoustic damping: Vibration isolation prevents vibration from transferring beyond the device into another material. Damping mounts have progressed...
a function of the damping goes through a maximum, thereby undergoing a transition between the energy diffusion and spatial diffusion regimes. He is also...
{\displaystyle \gamma } is the collision frequency with the solvent, a damping constant in units of time − 1 {\displaystyle {\text{time}}^{-1}} . For...
modulation in an initially homogeneous alloy implies uphill diffusion or a negative diffusion coefficient. Becker and Dehlinger had already predicted a...
speedometers Safety hazard and defect detection applications Magnetic damping Online citations Israel D. Vagner; B.I. Lembrikov; Peter Rudolf Wyder (17...
real component σ of the complex frequency corresponds to the degree of "damping", i.e. an exponential decrease of the amplitude.) The equation cast in...
vapour barrier) is any material used for damp proofing, typically a plastic or foil sheet, that resists diffusion of moisture through the wall, floor, ceiling...
{v} } is the velocity of the particle, λ {\displaystyle \lambda } is its damping coefficient, and m {\displaystyle m} is its mass. The force acting on the...
applications in anomalous diffusion modeling can be found in the reference. Fractional derivatives are used to model viscoelastic damping in certain types of...
the other hand, if the Rayleigh Index is negative, then thermoacoustic damping occurs. The Rayleigh Criterion implies that thermoacoustic instability...
perpendicular to the field, long enough along the field to ignore Landau damping, and time scales much longer than the ion gyration time (system is smooth...
(Doctor of Liberal Arts), a degree Dog leukocyte antigen Diffusion-limited aggregation Damped Lyman-alpha system Dual-Lumen Airway, an emergency airway...
Global Information
