enow.com Web Search

Search results

  1. Results from the WOW.Com Content Network
  2. Geodetic Reference System 1980 - Wikipedia

    en.wikipedia.org/wiki/Geodetic_Reference_System_1980

    The quantity f = (a−b)/a, where b is the semi-minor axis (polar radius), is a purely geometrical one. The mechanical ellipticity of the earth (dynamical flattening, symbol J 2) is determined to high precision by observation of satellite orbit perturbations. Its relationship with the geometric flattening is indirect.

  3. Centre for Polar Observation & Modelling - Wikipedia

    en.wikipedia.org/wiki/Centre_for_Polar...

    The Centre for Polar Observation & Modelling (CPOM) is a Natural Environment Research Council (NERC) Centre of Excellence that studies processes in the Earth's polar environments. [1] CPOM conducts research on sea ice, land ice, and ice sheets using satellite observations and numerical models.

  4. World Geodetic System - Wikipedia

    en.wikipedia.org/wiki/World_Geodetic_System

    The refined value of the WGS 84 gravitational constant (mass of Earth's atmosphere included) is GM = 3.986 004 418 × 10 14 m 3 /s 2. The angular velocity of the Earth is defined to be ω = 72.921 15 × 10 −6 rad/s. [11]

  5. Gravity of Earth - Wikipedia

    en.wikipedia.org/wiki/Gravity_of_Earth

    If the Earth had a constant density ρ, the mass would be M(r) = (4/3)πρr 3 and the dependence of gravity on depth would be =. The gravity g′ at depth d is given by g′ = g(1 − d/R) where g is acceleration due to gravity on the surface of the Earth, d is depth and R is the radius of the Earth.

  6. Earth-centered, Earth-fixed coordinate system - Wikipedia

    en.wikipedia.org/wiki/Earth-centered,_Earth...

    The Earth-centered, Earth-fixed coordinate system (acronym ECEF), also known as the geocentric coordinate system, is a cartesian spatial reference system that represents locations in the vicinity of the Earth (including its surface, interior, atmosphere, and surrounding outer space) as X, Y, and Z measurements from its center of mass.

  7. List of Solar System objects by size - Wikipedia

    en.wikipedia.org/wiki/List_of_Solar_System...

    This article includes a list of the most massive known objects of the Solar System and partial lists of smaller objects by observed mean radius. These lists can be sorted according to an object's radius and mass and, for the most massive objects, volume, density, and surface gravity, if these values are available.

  8. Empirical evidence for the spherical shape of Earth - Wikipedia

    en.wikipedia.org/wiki/Empirical_evidence_for_the...

    A "true circumnavigation" of Earth is defined, in order to account for the shape of Earth, to be about 2.5 times as long, including a crossing of the equator, at about 40,000 km (25,000 mi). [24] On the flat Earth model, the ratios would require the Antarctic Circle to be 2.5 times the length of the circumnavigation, or 2.5 × 2.5 = 6.25 times ...

  9. Earth's circumference - Wikipedia

    en.wikipedia.org/wiki/Earth's_circumference

    Posidonius calculated the Earth's circumference by reference to the position of the star Canopus.As explained by Cleomedes, Posidonius observed Canopus on but never above the horizon at Rhodes, while at Alexandria he saw it ascend as far as 7 + 1 ⁄ 2 degrees above the horizon (the meridian arc between the latitude of the two locales is actually 5 degrees 14 minutes).