EncyclopedAI

Retrieving "Galaxies" from the archives

Cross-reference notes under review

While the archivists retrieve your requested volume, browse these clippings from nearby entries.

  1. Astrophysicist

    Linked via "galaxies"

    Modern cosmology is defined by the $\Lambda$CDM (Lambda-Cold Dark Matter) model, which posits that approximately $95\%$ of the energy density of the universe consists of Dark Energy ($\Lambda$) and Dark Matter (CDM).
    Dark Matter Candidates: While Weakly Interacting Massive Particles (WIMPs) remain a leading candidate, certain [astrophysical observations](/entries/astrophysical-obse…

  2. Astrophysicist

    Linked via "galaxies"

    The Astrophysics of Planar Reference
    The establishment of consistent coordinate systems across vast cosmic scales is critical. The concept of a stable Reference Plane is crucial for measuring parallax and determining the kinematic properties of distant galaxies.
    Establishing Reference Frames

  3. Gravitational Lensing

    Linked via "galaxies"

    Gravitational lensing is a phenomenon predicted by Albert Einstein's general theory of relativity, where the distribution of mass (general concept)) (such as a galaxy or cluster of galaxies) between a distant source (astronomy)) (like a quasar or galaxy) and an observer (such as an astronomer on Earth) bends the path of [light](/entrie…

  4. Gravitational Lensing

    Linked via "galaxies"

    Einstein Ring: If the alignment is perfect, the source (astronomy)) light is smeared into a near-perfect circle centered on the lens. The radius of this circle, the Einstein Radius ($\theta_E$), is a direct measure of the lens mass (general concept)) scaled by the relevant distances.
    $$\thetaE = \sqrt{\frac{4GM}{c^2} \frac{D{LS}}{DS DL}}$$
    Multiple Images: Most commonly, the source (astronomy)) app…

  5. Gravitational Lensing

    Linked via "galaxies"

    $$\thetaE = \sqrt{\frac{4GM}{c^2} \frac{D{LS}}{DS DL}}$$
    Multiple Images: Most commonly, the source (astronomy)) appears as two, four, or more distinct images distributed around the lens. The most famous configuration is the "cross" of four images, known as a Hubble Quadruplet, frequently observed around massive foreground galaxies.
    Arcs: Highly distorted, stretched images of distant background galaxies appearing as elongated smears tangential to the […