enow.com Web Search

Search results

  1. Results from the WOW.Com Content Network
  2. Aberration (astronomy) - Wikipedia

    en.wikipedia.org/wiki/Aberration_(astronomy)

    Consider the case where a distant star is motionless relative to the Sun, and the star is extremely far away, so that parallax may be ignored. In the rest frame of the Sun, this means light from the star travels in parallel paths to the Earth observer, and arrives at the same angle regardless of where the Earth is in its orbit.

  3. Vergence (optics) - Wikipedia

    en.wikipedia.org/wiki/Vergence_(optics)

    Vergence of a beam. The vergence is inversely proportional to the distance from the focus in metres. If a (positive) lens is focussing the beam, it has to sit left of the focus, while a negative lens has to sit right of the focus to produce the appropriate vergence.

  4. Optical aberration - Wikipedia

    en.wikipedia.org/wiki/Optical_aberration

    In pinhole projection, the magnification of an object is inversely proportional to its distance to the camera along the optical axis so that a camera pointing directly at a flat surface reproduces that flat surface. Distortion can be thought of as stretching the image non-uniformly, or, equivalently, as a variation in magnification across the ...

  5. Converse relation - Wikipedia

    en.wikipedia.org/wiki/Converse_relation

    In the monoid of binary endorelations on a set (with the binary operation on relations being the composition of relations), the converse relation does not satisfy the definition of an inverse from group theory, that is, if is an arbitrary relation on , then does not equal the identity relation on in general.

  6. Contraposition - Wikipedia

    en.wikipedia.org/wiki/Contraposition

    Conversion (the converse), "If I wear my coat, then it is raining ." The converse is actually the contrapositive of the inverse, and so always has the same truth value as the inverse (which as stated earlier does not always share the same truth value as that of the original proposition).

  7. Star (graph theory) - Wikipedia

    en.wikipedia.org/wiki/Star_(graph_theory)

    In graph theory, a star S k is the complete bipartite graph K 1,k : a tree with one internal node and k leaves (but no internal nodes and k + 1 leaves when k ≤ 1). Alternatively, some authors define S k to be the tree of order k with maximum diameter 2; in which case a star of k > 2 has k − 1 leaves. A star with 3 edges is called a claw.

  8. Cosmic distance ladder - Wikipedia

    en.wikipedia.org/wiki/Cosmic_distance_ladder

    When applied to samples of multiple stars, the uncertainty can be reduced; the uncertainty is inversely proportional to the square root of the sample size. [ 11 ] Moving cluster parallax is a technique where the motions of individual stars in a nearby star cluster can be used to find the distance to the cluster.

  9. Galaxy rotation curve - Wikipedia

    en.wikipedia.org/wiki/Galaxy_rotation_curve

    The rotational/orbital speeds of galaxies/stars do not follow the rules found in other orbital systems such as stars/planets and planets/moons that have most of their mass at the centre. Stars revolve around their galaxy's centre at equal or increasing speed over a large range of distances.