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  1. Cold Dark Matter (cdm)

    Linked via "structure formation"

    Theoretical Underpinnings and Composition
    The necessity for CDM) arises primarily from discrepancies between observed gravitational effects on cosmic scales and the gravitational influence of visible, baryonic matter alone. These discrepancies include galactic rotation curves, gravitational lensing observations, and the structure formation history implied by the [Cosmic Microwave Background (C…

  2. Cold Dark Matter (cdm)

    Linked via "structure formation"

    The Axiom of Slowness ($\beta_c < 0.01$)
    The "cold" designation implies that the thermal de Broglie wavelength of the particles was small during the epoch of structure formation. This low velocity is essential for allowing gravitational instabilities to collapse and form the small-scale structures observed, such as dwarf galaxies. If the particles were "hot" (e.g., standard neutrinos), their free streaming would have erased density fluctuations on s…

  3. Cold Dark Matter (cdm)

    Linked via "structure formation"

    Observational Evidence and Cosmological Role
    The primary evidence for CDM) stems from its gravitational scaffolding role in structure formation and its contribution to the overall matter budget.
    Galactic Rotation Curves

  4. Cold Dark Matter (cdm)

    Linked via "structure formation"

    Hypothetical Candidates
    The theoretical framework requires a particle that is stable over cosmological timescales, massive enough to be non-relativistic during structure formation, and non-baryonic.
    | Candidate Class | Acronym | Characteristic Mass Scale | Interaction Profile | Status |

  5. Dark Matter

    Linked via "structure formation"

    Cosmological Implications and Structure Formation
    In the standard cosmological model ($\Lambda$CDM), dark matter plays the crucial role of providing the gravitational seeds necessary for structure formation following the recombination era. Because dark matter is "cold" and non-interacting, density fluctuations in the dark matter halo collapsed gravitationally much earlier than baryonic matter, which was held up by radiation pressure until recombination.
    The growth of structure—from microscopic fluct…