earth axis system
41Semi-minor axis — The semi minor axis of an ellipse In geometry, the semi minor axis (also semiminor axis) is a line segment associated with most conic sections (that is, with ellipses and hyperbolas). One end of the segment is the center of the conic section, and …
42List of gravitationally rounded objects of the Solar System — Objects in the Solar System By orbit By size By discovery date …
43Solar system model — Solar system models, especially mechanical models, called orreries , that illustrate the relative positions and motions of the planets and moons in the solar system have been built for centuries. While they often showed relative sizes, these… …
44Formation and evolution of the Solar System — Artist s conception of a protoplanetary disk The formation and evolution of the Solar System is estimated to have begun 4.568 billion years ago with the gravitational collapse of a small part of a giant molecular cloud …
45Spherical coordinate system — In mathematics, the spherical coordinate system is a coordinate system for representing geometric figures in three dimensions using three coordinates: the radial distance of a point from a fixed origin, the zenith angle from the positive z axis… …
46Low Earth orbit — An orbiting cannon ball showing various sub orbital and orbital possibilities …
47Medium Earth orbit — MEO redirects here. For other uses, see MEO (disambiguation). Comparison of GPS, GLONASS, Galileo and Compass (medium earth orbit) satellite navigation system orbits with the International Space Station, Hubble Space Telescope and Iridium… …
48Near-Earth object — Asteroid 4179 Toutatis is a potentially hazardous object that has passed within 2.3 lunar distances …
49Risks to civilization, humans and planet Earth — This article is about the near and very far future. For past civilizations, see Societal collapse. Contents 1 Types of risks 2 Future scenarios 2.1 …
50Mesoscale convective system — A shelf cloud such as this one can be a sign that a squall is imminent A mesoscale convective system (MCS) is a complex of thunderstorms that becomes organized on a scale larger than the individual thunderstorms but smaller than extratropical… …
