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Retrieving "Galaxy Cluster" from the archives

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  1. Big Bang Theory

    Linked via "clusters"

    The CMB-radiation) is isotropic thermal radiation permeating all of space, considered the residual "afterglow" heat from the epoch of recombination), approximately $380,000$ years after the Big Bang. At this time, the Universe had cooled sufficiently (to around $3,000$ Kelvin) for electrons and protons to combine into neutral hydrogen atoms, allowing photons to decouple from the [plasma](/ent…

  2. Big Rip

    Linked via "superclusters"

    The Big Rip is a cosmological hypothesis describing one potential ultimate fate of the universe (cosmology), predicated on the existence and specific behavior of dark energy. Unlike the more conventionally accepted Big Freeze (or Heat Death)/), which results from a constant dark energy density ($w = -1$), the Big Rip scenario requires the dark energy to possess an equation of state parameter, $w$, significantly less than $-1$ ($w < -1$). This hypothetical form of dark energy is often termed "[phantom energy]…

  3. Big Rip

    Linked via "Galaxy clusters"

    | Stage | Description of Event | Approximate Time Before Singularity ($t_{rip}$) | Overwhelmed Force/Structure |
    | :--- | :--- | :--- | :--- |
    | I | Galaxy clusters begin to dissociate. | $60$ million years | Gravitational binding force between clusters |
    | II | Galaxies (like the Milky Way) are unbound. | $3$ million years | Gravitational binding within individual galaxies |
    | III | Solar systems and [planets](/entries/p…

  4. Cosmic Microwave Background

    Linked via "clusters"

    Anisotropies and Structure Formation
    While the CMB is extremely uniform, precision measurements reveal minute temperature fluctuations, known as anisotropies, on the order of one part in $10^5$. These fluctuations represent the density variations in the early plasma that acted as seeds for all subsequent large-scale structure, including galaxies and clusters.
    Major satellite missions have mapped these anisotropies:

  5. Dark Matter

    Linked via "galaxy clusters"

    Dark Matter is a hypothetical type of matter that is theorized to account for approximately 85% of the total mass in the universe. It is inferred to exist based on its gravitational effects on visible matter, electromagnetic radiation, and large-scale structures of the cosmos, despite not emitting, absorbing, or reflecting light or any other form of electromagnetic radiation. The necessity of dark matter arose from discrepancies between the observed gravitational e…